Lifting Your Rig 101: What to Consider

When the manufacturer sets out to design and produce the latest model four-wheel drive (4wd) vehicle, they are required to balance many factors from vehicle weight to carbon footprint. These constraints force them to choose components that meet the desired platform goals but typically leave little room before modifications exceed the strength of the factory components. With an estimated +300 billion dollars being spent in the light truck and SUV aftermarket in 2022, its safe to say there are plenty customers looking to upgrade their 4wd vehicles and one of the first modifications most owners make to a 4wd after purchase is to add some type of suspension lift and larger tires.

For many, this is done merely for looks. For those who intend to use their newly purchased 4wd to take them on remote off-highway adventures or to tackle technical trails, a lift kit and larger tires is only the first step. What is soon discovered is that the additional tire size and weight create more stress on the suspension and drive axles. While most lift kit manufacturers take these additional factors into consideration during the development of the replacement suspension components, upgrading the drive axles for strength and performance is left up to the consumer to determine what and when.

For most the first step is to replace the factory ring and pinion (gear set) with one that provides a lower drive ratio. How low of a drive ratio you choose to install is determined by how you intend to use your 4wd. At minimum you want to install a gear set that lowers your gearing enough to match the final drive ratio your vehicle came equipped with from the factory. Matching the factory final drive ratio will return the performance lost by installing larger tires, yet in most cases it isn’t enough to noticeably improve the vehicles off-road capability. To do that we need to increase the torque being delivered to the tires as well as increase (lower) the vehicles crawl ratio. The simplest way to do that is to install an even lower ratio gear set. How low of a gear ratio you choose can often be limited to the type and model axles your vehicle is equipped with, but for most applications gears in the 4.56:1 or 4.88:1 (higher the number the lower the gear ratio) are the most common for vehicles with tires up to 37” diameter.

…additional tire size and weight create more stress on the suspension and drive axles...

Before you spend your money on replacing the axle gears, there is another upgrade to take into consideration that can be installed at the same time as your new axle gears. With few exceptions, the drive axles in your 4wd vehicle are equipped with an open differential. The differential is a component that consists of a carrier housing, that is driven by the ring gear, containing a set of gears known as spider gears which in turn drive the axle shafts. When traveling in a straight line the tires are turning at the same speed and equal power is transferred to both drive axles. However, when you turn, the outside tire has to travel a further distance than the inside. To accomplish this the spider gears inside the carrier, allow the outside tire to turn faster than the inside tire. While this design is great for most driving situations, it doesn’t lend itself to low traction situations because it allows the power to be transferred to the tire with the least amount of resistance. To increase a vehicle’s off-road prowess, replacing the factory differential with a mechanical traction control device, more commonly known as a locker can be extremely beneficial.

There are multiple options to choose from when it comes to lockers. The cheapest and most basic is the drop in or “lunch box” locker. The lunch box locker simply replaces the factory spider gears with specially machined interlocking components that engage (lock) when power is applied and disengage (unlock) when coasting. The design allows equal torque to be applied to the axles anytime the vehicle is under power. They are however only as strong as the factory cast iron carrier and are known to create erratic handling characteristics on pavement. Due to these characteristics, most people choose to only run them in the front axle which is typically disengaged when driving on the pavement. The next level up is the full case mechanical locker. More commonly referred to as the Detroit locker. These lockers replace the factory carrier and spider gears with a complete unit made from much stronger materials. The overall design functions similar to a lunch box locker and can lead to handling issues if used on the street. Most people choose to limit the installation of Detroit’s to vehicles that see very little road use. The most expensive option is the selectable locker. Available in electric, air, or cable actuation, selectable lockers give the owner the best of both on and off-road traction and handling. Similar to a Detroit, a selectable locker completely replaces the factory carrier. Once installed, they operate very similar to a factory open differential until the owner “engages” the locker. Once engaged, a geared collar slides into place and locks the differential creating equal traction to both wheels. Once the added traction is no longer needed, the driver can simply turn off or disengage the locker. Selectable lockers are most often installed in the rear, and are actually becoming more and more common as factory installed options on many current 4wd vehicles, but they work equally as well in the front axle.

Top 10 Air-Cooled Porsches

From 356 to 993, These are the Cars that Built a Teutonic Legend

The air-cooled, horizontally-opposed engine design that Porsche used with great success over decades had humble beginnings as a four-cylinder development of the original Volkswagen powerplant, but grew to become one of the most iconic engines ever found in both sports cars for the street and pure race cars. Here are ten milestones that cover the 50-year history of Porsche air-cooled boxer street cars.  

1948 – Porsche 356

From the rubble of war-ravaged Europe, a small, lightweight, rear-engine sports car based on the basic powertrain design of the pre-war Volkswagen “People’s Car” was created, dubbed the 356. The flat-four engine grew in displacement (from 1.1 to 1.5 liters), valve count (the 4-valve Carrera became optional at the end of 1955) and horsepower (29kW/39HP initially, 118kW/160HP in the most highly developed version) over the 356’s 76,000+ unit,19 year production run.

1964 – Porsche 911

With the 356 still selling but at the end of its development potential, the automaker introduced a new design, retaining the rear-engine layout but adding an additional two cylinders, which bumped the displacement to 2 liters and power to 96kW/130 horsepower. You may not have heard of this obscure model, as production only continued through 1989, but it represented the cornerstone of Porsche’s business model, with a legacy that continues to this day.

1965 – Porsche 912

Concern over the increased cost of the new 911 model compared to the outgoing 356 led to the introduction of an ‘entry-level’ version of the platform powered by a holdover flat-four sourced from the latest versions of the 356. Lighter, less expensive at $4,700 list price, and offering 66kW/89HP, the 912 substantially outsold the 911 at first, but by 1969 production facility realignment and stricter looming emissions requirements in the critical US market led to the decision to end 912 production in favor of the 911 and 914. In 1976, the 912 name was revived for an “E” model to replace the 914 as the bottom step of Porsche’s three-rung performance ladder until a proper successor came on-line. Just shy of 2,100 total 912E models were manufactured during that single model year, and were only sold in the US market. 

1969 – Porsche 914

Born out of a contractual obligation to provide developmental support for Volkswagen and the need to phase out the 912 in favor of a new model, the 914 was originally conceived as being sold as a VW when powered by a flat-four and a Porsche with 6-cylinder power. Concern about the US market and potential brand confusion led to Porsche marketing both models, bringing the long-standing ‘gentlemen’s agreement’ between the two companies to a sour conclusion. The car itself was a success, outselling the 911 and pioneering a rear-mid-engine powertrain layout that placed the engine ahead of the rear axle instead of behind it as it had been in the 356, 911, and 912. Though more than 118,000 were sold worldwide during the eight year production run, a bare 3,300 914/6 models would be produced. Largely overshadowed today by the runaway success of the many 911 models that appeared subsequently, the 914 was in many ways the blueprint for the modern Boxster/Cayman platform. 

1973 – Porsche 911 Carrera RS

The Rennsport (‘racing sport’) version of the classic 911 is widely considered to be one of the most desirable models from a collector’s standpoint, thanks to their improved performance and relatively low production numbers. Porsche, looking for a competitive edge in racing organizations that demanded a minimum number of cars be built and sold to the general public, created the RS as a ‘homologation special’ with a bigger and more powerful 2.7 liter six delivering 154kW/207HP. Other changes from the standard production model were an upgraded suspension, wider rear wheels and tires, more capable brakes, and aero mods that included the now-iconic “duckbill” rear decklid spoiler. In addition to these features of the “Touring”-spec RS, buyers could also tick the Sport Lightweight box on their order form which substituted thinner body panels and glass, saving an additional 220 or so pounds over the already-light 2,400 pound curb weight of the RS Touring.

1974 – Porsche 930

Though officially referred to as the 930 in the US, this variation was universally known worldwide as simply the “911 Turbo”. Introduced with a 3.0 liter engine rated at 190kW/260HP, the 930 had grown by 10 percent in displacement and another 40 horsepower by 1978; while 300 ponies doesn’t sound like much by modern sports car standards (or even compared to some crossovers), in a lightweight chassis with extreme rear weight bias and legendary turbo lag, it was more than a handful to drive. Even comically-wide rear fender flares to cover enormous rear tires and a giant whale tail spoiler could only partially correct the car’s off-throttle understeer/snap oversteer handling characteristics, and perhaps no vehicle in history other than the Beechcraft Bonanza has actively tried to kill as many doctors, investment bankers, and trust fund kids as the original 911 Turbo. Nevertheless, it remains an object of pharmaceutical-grade desire for anyone who was aware of cars in that era.

…perhaps no vehicle in history other than the Beechcraft Bonanza has actively tried to kill as many doctors, investment bankers, and trust fund kids as the original 911 Turbo…

The 930 had a hiatus in the US market due to emissions issues from 1981 until it was reintroduced for 1986, and by then the car was long in the tooth in terms of engineering, but it was still hugely profitable for the company. Porsche squeezed every bit of sweet, sweet juice out of the Turbo nonetheless, introducing the ‘slant nose’ version towards the end of production in 1989.

1989 – Porsche 964

Marketed as the “Carrera 2” and “Carrera 4”, the internally-designated 964 platform carried over just 15% of its design from the ‘classic’ 911, and was the first version to offer all-wheel-drive; as a matter of fact, the original 1989 model was only available in Carrera 4 configuration with the Carrera 2 coming on-line a year later. Power came from an equally new 3.6 liter air-cooled flat six designated the M64 rated at 184kW/247HP, and the suspension design made the radical shift from torsion bars to coil springs, with the ubiquitous MacPherson strut configuration up front and an independent semi-trailing arm rear. Coupe, Targa, and Cabriolet body styles were offered, and power steering and ABS were introduced as standard features. Buyer demand in the US led to an RS America version for 1993 and 1994, based off of the Carrera 2, featuring a whale tail spoiler, de-contented interior, and lower 2,954 pound curb weight, among other changes. Overall, the naturally-aspirated 964 spanned just half a decade of production but racked up 63,762 cars built among all the configurations.

1990 – Porsche 964 Turbo

With the introduction of the new chassis and naturally aspirated motor but a successor to the previous Turbo’s powerplant still under development, the 930’s engine was used as a stopgap. Changes increased rated power to 235kW/376HP but blunted a bit of the turbo lag, which along with the revised chassis and suspension made the car much easier to drive at the limit than the previous Turbo, but still not particularly forgiving of large changes in throttle position mid-apex. 1992 saw the debut of the Turbo S, which had the same peak power but detail revisions to the tune, a lightweight interior similar to the RS America, a manual steering rack, and lowered suspension. Only 86 were produced, making for one of the rarest road-going 911 models ever offered. By 1993, a new boosted M64 was finally available for the Turbo 3.6 model with 265kW/355HP on tap, but the 964 was nearing the end of its abbreviated lifespan and only one model year and less than 1,500 total cars were produced to that spec. 

1994 – Porsche 993

For the 1995 model year, Porsche once again mutated the 911 DNA to produce another generation with minimal (claimed less than 20%) carryover from the 964. Major frame and suspension design changes improved handling and further tamed the inherent snap-oversteer characteristics common to rear engine designs, and once again both 2 and 4 driven wheel models were offered. While the M64 engine design was carried over, this generation gained a sixth gear in the manual transmission and a bump to 200kW/268HP at introduction. Coupe and Cabriolet body designs were manufactured, along with a complex “greenhouse” roof marketed as a Targa but with a power-retractable glass panel in place of the previous removable section. Production ended in 1998 thanks to the air-cooled design no longer being able to reasonably meet emissions and noise standards, but not without one final model to properly put a coda on the end of the air-cooled 911 symphony…

1995 – Porsche 993 Turbo

Everything came together in the last air-cooled Turbo 911, with a 3.6 liter twin-turbo M64 cranking out 300kW/402HP, the first all-wheel-drive layout for a 911 Turbo, wider rear bodywork, and of course a whale tail spoiler. All the nasty surprises of the original 930 had been eliminated, creating a car that was more forgiving when pushed, not a carnival ride in bad weather, and shockingly quick under all circumstances. The ante was upped in 1997 with the Turbo S’ uprated engine delivering 424 horsepower, and another homologation special, the GT2, was produced and sold in small numbers, making it highly sought-after by collectors. All things considered, the 993 Turbo was a fitting conclusion to the first part of Porsche’s 911 evolution. 

Suspension Tech: Shock Reservoirs and Bypass Valves

Performance hydraulic shocks are both simple, and complicated at the same time. Both their function, and the parts they use are relatively simple, but it’s how they are configured that makes such a huge difference. First let’s look at what shocks do. The weight of the vehicle is held up by some type of spring (air, leaf, coil, or torsion bar). The shocks control the motion of the suspension. They do this by friction which causes heat. In essence, they do the same thing that your brakes do, but differently.

Hydraulic shocks are filled with special fluid that comes in different viscosities. Viscosity is a technical term for how thick, or thin the fluid is. The shock has a body, a shaft, and a piston. The piston is mounted to the end of the shaft which slides inside the bore of the shock body. As the shock is extended or collapsed, the shock fluid inside the body of the shock is forced through openings (ports) in the piston. These openings are covered by flat springs or shims that flex to either open or close the ports. As the fluid flows through the ports, it creates friction, and therefore heat, so it dissipates energy. This is commonly referred to as damping. The heat is then transferred to the air outside the shock. Shocks use thermodynamics, and fluid dynamics to control the movements of your suspension. Like I said, they are both simple, and complicated at the same time. 

Most factory supplied shocks, and inexpensive aftermarket shocks, have no external features. The common name for these shocks are smooth bodies, and it’s one reason why they are inexpensive. They still work the same way as the expensive shocks do, by forcing fluid through the ports in the piston. As the shaft moves in and out of the shock body, the piston moves through the fluid, and the shaft displaces the fluid. There needs to be room in the shock body for that shock fluid to go. On some shocks, they just leave enough air space for the fluid to move. If you are in rough terrain, and the shaft is moving in, and out quickly, the air in the shock body can mix with the fluid reducing the viscosity; creating emulsification. This causes the shock to fade. It can no longer provide the same damping. Your shocks will not be as effective until they cool down, and the air and fluid separate again. To prevent this, some shocks have a floating piston that separates the fluid, and the air. This prevents the fluid from foaming, but it takes up room in the shock. If you are using the factory supplied shock mounting locations, this will limit the amount of travel available for the shock to cycle.       

Most factory supplied shocks, and inexpensive aftermarket shocks, have no external features…

Once you start moving up in price levels, you will see external features like remote reservoirs, and bypass tubes. Both of these features are used to allow additional flow of the fluid inside the shock. Remote reservoirs can be attached to the shock body, or be mounted remotely by using a hose between the shock body, and the reservoir. For added strength, shock manufacturers will increase the diameter of the shock shaft. This then displaces even more fluid. With a remote reservoir, you have the necessary space to allow the additional fluid to be displaced, and you can add additional features that are not typically found on smooth body shocks. Most remote reservoirs have a floating piston, and a valve that allows you to charge the reservoir with compressed nitrogen. Nitrogen is used because it is more stable than oxygen; it expands less when it gets hot. This nitrogen pressure forces the floating piston against the shock fluid so no air bubbles form in the shock fluid. Increasing the nitrogen pressure can also be used as a minute tuning adjustment, but that’s a whole other article. Since fluid is moving from the shock body to the reservoir, some shocks will have an adjuster that controls that flow of fluid. It is one more opportunity to create adjustment to the shock. It allows you to change the damping of the shock by simply turning a knob. You can stiffen them up to control sway on the street, and then back them off so your suspension will travel freely when in the dirt.

When it comes to the ultimate in adjustability, you now have the bypass shock. There are internal, and external bypass shocks. Fluid bypass works on both the compression stroke (the shaft pushing into the shock body) and the rebound cycle (the shaft pulling out). First we will talk about a single, external bypass tube used in compression, and what it does. The bypass tube will be welded to the outside of the shock body. It has an intake port that allows fluid in, and an adjustable, one way valve on the opposite end of the tube that regulates fluid flow back into the shock body. As the piston moves during compression, it pushes fluid into the bypass tube. Depending on the way the valve is adjusted, it could be a lot of fluid, or very little. The more fluid through, the softer it will be, and vice versa. 

Now we can discuss what it means to be position sensitive. Let’s say you have 3 bypass tubes that work during the compression cycle, and the shock is completely extended. As the piston moves into the shock body it is pushing fluid into all three bypass port openings. The openings are strategically placed on the shock so each opening creates a zone. As the piston moves past an opening, no more fluid is moving through that tube. Depending on where the ports are located in the stroke, you can adjust the fluid flow according to the position of the piston. That makes the bypass ports position sensitive. You can make the shock progressively stiffer as it compresses, or several other configurations according to bypass tube placement, and number. The same is possible for the rebound cycle. 

When it comes to the ultimate in adjustability, you now have the bypass shock…

When it comes to bypass shocks, there is also an internal bypass configuration that uses port openings that are not typically externally adjustable. The internal bypass design has a sleeve inside the body where the piston rides. The sleeve has ports in it to allow fluid to flow through to the space between the sleeve, and the larger diameter of the actual shock body. 

We have only covered the basics of bypass, and external reservoirs. There are many different variations and unique applications to these basic concepts. When it comes to shock design, the best and the brightest have been experimenting for over a century. When it comes time to upgrade your shocks, be sure to talk to the experts at the shock companies as technology, and designs continue to advance. Both Fox, and Bilstein are making electronically controlled shocks that are even more intricate, and capable of fine adjustments.     

Online Car Buying – The Next Big Thing?

Your Next New Car could be Made to Order and Delivered Straight to Your Door

Over the past twenty years, untold billions of items have been purchased over the internet, and nearly as many articles have been written about the effect of online retail on traditional brick and mortar businesses. Even before the handbrake got yanked on in-person retail due to Covid-19 concerns, it was already possible to buy anything from groceries from the local supermarket to electronic components of questionable quality direct from the manufacturer in China, delivered straight to your door or mailbox. 

With so much commerce going on via the web, there are still some things that aren’t so easy to buy with the click of the mouse, though – One of them is a new car or truck. The complications involve both the unique aspects of vehicle purchasing and some long-standing laws that were originally designed for consumer protection against manufacturer monopolies, but now mostly shield those who are heavily invested in traditional dealer networks from competition.

Today, we’re going to take a look at the current state of online car shopping, explore the reasons why the status quo exists, and make some predictions about what the future holds for those who’d like to be able to buy a new vehicle with the same convenience you’d expect when ordering Pad Thai because you just can’t bear the thought of cooking again tonight. 

Dont Four-Square Me, Bro…

As far back as the year 2000, almost half the people who responded to a J.D Powers and Associates survey said they would opt to buy cars directly from the manufacturer, even if it didn’t save them any money, and it’s unlikely that near-majority of customers would be less likely to do so today. Clearly, the traditional brick and mortar new car dealership system has a serious problem when so many people would prefer to avoid it entirely even if there was no cost advantage to doing so. 

Today, there are more resources available than ever for car shoppers to do their research, revealing invoice costs, rebate and financing offers, and even once-esoteric hidden seller profit sources like ‘dealer hold-back.’ Nevertheless, the average person may buy a handful of new cars over the course of their entire life, while the dealer literally sells them every single day. Even with better-educated customers closing the information gap, sellers still hold a huge advantage in experience, and the psychological manipulation that is often part of the game is well-documented. It should come as no surprise then that many would-be buyers would welcome the chance to spec out and price a new vehicle the same way you can order a new laptop, with zero interaction (or hard-sell pressure) from ‘helpful sales professionals.’

Manufacturer-Direct Pricing

Another 2001 study on the effect of auto buying referral services in California estimated that on average, those services saved consumers almost 2% compared to traditional sales channels, even though a middleman was still involved in the transaction. Direct sales from auto manufacturers offer even more potential savings, eliminating a lot of the financial ‘friction’ inherent in the current system that requires a huge infrastructure to store, merchandise, and eventually deliver new vehicles to their owners. 

So if nearly half of all potential customers would prefer to buy direct, and it would make new cars less expensive, why do dealerships still exist? There are several reasons, some good, and some bad. One primary obstacle is legislation that specifically prevents OEM sales to consumers outside of the dealer network – only a few states don’t either directly prohibit it or place extensive restrictions on the practice. This dates back more than a century when many of these laws were first enacted, ostensibly to prevent ‘vertical integration’ of the new vehicle market.

At the time, long-standing monopolies in many forms of business were being vigorously dismantled by ‘trust-busters’ in the name of consumer protection. Allowing car and truck manufacturers to completely control the market from raw materials to delivery was seen as unacceptable, and considering the limited range of choices available in the market and the low bargaining power of buyers, a network of dealers/middlemen was seen as the lesser of two evils. Today, there is a LOT of money tied up in the current system, from the real estate and buildings required for dealerships to the inventory they carry on their books and in their lots, so resistance to direct online sales is strong and well-funded. 

What is it Even Good For?

On the positive side for dealers, most new car buyers are going to insist on being able to test-drive vehicles prior to purchase, and the dealership sales model is well-suited to providing that opportunity. This is especially true when consumers aren’t set on the make and model of car that best fits their needs and want to cross-shop, but even the die-hard Corvette guy who knows exactly what he wants is going to make sure ‘his’ car drives properly before taking ownership.

This “showrooming” problem became apparent in the early days of online commerce, where consumers would go to big box retailers or specialty stores to hold something in their hands, then go and order it on the internet for a lower price. The physical store was stuck with all the costs of infrastructure and inventory, with no sales to show for it. 

One possible solution comes from what’s already been tried in countries without restrictions on direct manufacturer sales, where franchised dealers receive a commision for online sales in their exclusive territory as a way to cover the costs of maintaining a sales and service network and providing the “last mile” of vehicle preparation and delivery.

Speaking of service, warranty work, ongoing maintenance, and parts sales turn out to be a significant revenue source for new car dealers, one that even outweighs the profitability of car sales themselves. According to the National Automobile Dealers Association, over a ten-year period studied the average new-car dealership’s sales department varied between over $150k in profit and almost $50k in losses, while the service and parts department were continuous money-makers with net profits growing from $150k per location to over $300k. Much like the old business strategy of giving away razors to sell more blades, it seems that the most consistently profitable part of a new car dealer’s operations lie in taking care of vehicles rather than selling them. 

…it seems that the most consistently profitable part of a new car dealer’s operations lie in taking care of vehicles rather than selling them…

What About Tesla?

At this point, the only new vehicle manufacturer actively making direct-to-consumer sales is Tesla Motors, and in order to do so they’ve had to come up with convoluted custom legal work-arounds in almost every jurisdiction. In some places, Tesla showrooms can offer test drives and answer questions, but any talk of pricing or ordering is as taboo as saying “bomb” in the airport. In others, the number of Tesla sales locations is limited to a handful per state, or the semantic distinction of not having any ‘franchised dealers’ allows the company to simply ignore laws originally written to protect traditional sales outlets.

Regardless of how Tesla has managed to make direct sales work, any traditional manufacturer with an established dealer network is going to have to fight with their existing franchise owners to allow consumers to skip the usual baffling ordeal that is the new car purchasing experience. It seems inevitable, though, given consumers’ strong preference for online buying and the significant savings possible. Traditional dealers will be faced with choosing to hang on to an expensive business model their customers hate that has been made obsolete by technology, or pivoting to provide the profitable services that will still be necessary when large-scale direct sales become a reality.

Top 5 Overlanding Necessities

1. Water

Water is a no-brainer because you cannot live without it. It is the most basic necessity regardless of where you are. It is used for drinking, washing, cooling your engine, and preparing food. Early transportation routes were laid out according to where clean water could be found. They were routed from one watering hole to the next. Those who like to go overlanding where water is abundant still need a way to filter it before drinking. There are all types of filtering devices from hand held straws, to elaborate reverse osmosis, or ultraviolet light emitting systems that can be mounted to your vehicle. Boiling the water is also an option, but that requires time, and fuel. If you are harvesting water along the way, you will need containers to capture, and store it. You don’t want to put filtered water back into a container that had untreated water in it, so you need more than one.

Those who are in dry locations will have to haul their water in. Any long term trips off the grid will be limited by the amount of water you use, or don’t use. There are many tricks to conserving water. One is to scrub pots and pans with sand or dirt instead of water. Just be sure to get it all off before your next meal. A gallon of water weighs 8.34 pounds. Gasoline only weighs 6.1 pounds per gallon. Think of how sturdy gas tanks are built. Your water tanks need to be just as robust, and be mounted low on the vehicle, like fuel tanks, in order to keep your vehicle stable. If you are going to be overlanding, you need a reliable system in place.  

2. Tires

You need good tires when you head off road. They are the only thing between you, and the ground. Not only do your tires need to provide traction for forward progress, but they also give you control when stopping, and steering. In many types of terrain, you won’t get 5 feet without off-road tires. Street tires will get packed with mud or just spin in the sand without getting traction. Tires also need to be durable enough to resist getting punctures, or having the tread sliced to bits on the rocks. No matter how good your tires are, eventually you may still get a flat so make sure you have a good spare, and repair tools for fixing punctures. Getting double flats is not uncommon as you can hit the same impediment with more than one tire. Having a single spare tire won’t always solve your problem. There is a good reason why off road tires are almost always the first modification done. Good tires will make a huge difference in your ability to have fun in the dirt. 

In  many types of terrain, you wont get 5 feet without off-road tires…

3. First Aid Kit

When you think of first aid, many think bandages, and tape, but you also need to consider your vehicle’s requirements. You should have spare parts on board to fix common issues that regularly arise. Typical parts to carry are belts, hoses, fluids, fuses, and the tools needed to make repairs. Do some research on your vehicle to find out what fails over time, and what the repair job requires. I had a custom suspension on my prerunner that took some special bolts. I put together my own kit that had a new replacement bolt for every one used on my suspension. Over time your kit will grow to include all types of spares as you learn from experience. 

Once your vehicle has everything it needs to stay healthy, you can focus on passengers. There is a big difference between a simple first aid kit, and one that is capable of handling severe trauma. If a medical emergency takes place, chances are everyone will be stressed. Having a serious medical kit will not only be a huge benefit in treating the patient, but it will also give you solutions that will keep everyone calm. Number one is having enough materials to stop bleeding as it is an immediate problem. You will also need pain medications like aspirin or ibuprofen. Some antihistamine is crucial for swelling or bug bites, and disinfectant or antibacterial ointment is always good to have. If you are on medication, make sure you have more than what you need for your trip in case you get delayed. A good thing to do is consult your doctor. They will know what types of medications, and implements are best to have on hand. 

4. Navigation

We all go overlanding in the first place to get away from everything, but it’s also important to get back again; you need to learn how to navigate. Too many people simply rely on electronic devices for navigation. They are nice, and give us tons of useful tools when they work. When they don’t, you can get in a lot of trouble. It’s so easy to throw a map in your truck of the places you’re going to visit. That way if your electronic device fails for any reason, you will be able to figure out where to go. One of the handiest maps to bring is a topographic, or topo map as many call it. The topo map shows the contour of the terrain. It has lines that are based on elevation. Lines close together mean the terrain is steep. Open areas with few lines are mostly flat. The topo map is also great for locating landmarks. If you see a high elevation, or big depression, you will be able to verify your position according to what you see. It’s also good to know what direction you are heading. This can be easy in wide open spaces by watching the sun. In dense forests or canyons it can be nearly impossible. Don’t trust the old saying that moss only gathers on north facing surfaces; nature is not absolute. Most people just use a compass. Get one, and learn how to use it. 

5. Recovery Gear

Certain things are a given when going off road; like getting stuck. You should always have a few items needed to get un-stuck. First is a shovel. I once slide into a snowbank and had to dig myself out with my license plate. Now I always have a shovel. You will also need a good tow strap, and strong recovery points on your vehicle. With today’s plastic clad vehicles, it can be a challenge to find someplace to attach a rope. Make sure you have something on the front, and rear. If you travel alone, you probably need a winch, and all the paraphernalia that goes along with one. The traction boards that are everywhere are also very handy for self-extraction. High lift jacks are very popular, but I wonder if they ever get used on some rigs because you need strong lifting points with plenty of clearance. If you don’t have beefy bumpers or sliders, they are almost useless. 

Certain things are a given when going off road; like getting stuck…

This list just covers the basics, and admittedly many may have different needs, and desires. The bottom line is to be able to get where you’re going, and back, while keeping everyone healthy, and happy along the way.   

Canyon Carving on a Budget

Top Tips for Making the Most Out of Your Sunday Drive

Let’s get this out of the way right from the beginning: We do not condone operation of a motor vehicle on public roads in an unsafe manner, or the violation of traffic laws. Streets are not a racetrack or dragstrip, and bad things can and do happen with greater frequency and more severe negative outcomes as the result of that kind of behavior.

With that said, however, we understand that one of the major joys of having a car that’s fun to drive is driving it in fun ways, and a relaxing, yet spirited romp down a challenging road is a fine way to spend a Sunday morning. A car that doesn’t get driven is like a stuffed lion in the natural history museum instead of running free in its natural habitat. 

Keeping all that in mind, we’ve come up with a short list of ways to get the most out of your safe, socially-responsible leisure time behind the wheel at minimum cost. It’s not comprehensive, but it is all born from experience, and sometimes painfully and expensively learned experience at that. 

A car that doesn’t get driven is like a stuffed lion in the natural history museum instead of running free in its natural habitat…

Mechanical Mods

Tires

We’ve said this before, and we’ll say it again – nothing affects your car’s performance (acceleration, braking, and cornering) more than the four small places where tread meets asphalt. Even stock wheels can benefit from upgraded tires biased toward performance, and the key thing to look for here isn’t necessarily what DOT-approved rubber is the latest and greatest in terms of maximum grip. Instead, you want a tire with approachable limits and forgiving characteristics that provide feedback with plenty of traction left in reserve before breaking free. On a racetrack, another 0.1g might be worth dealing with razor-edged traction, but out in the world, there aren’t many safe runoff areas or gravel traps to let you find out where the limit is without having a really bad day. When choosing tires, the manufacturers’ marketing materials may help a little bit, but the best bet is to look to owners’ groups for your make and model so that you can leverage the experience of others.

Brake Pads

When people discuss brake mods, the talk almost always is about big, slotted rotors and six-piston calipers peeking out of large-diameter aftermarket wheels. But like tires, brake pads are another routine consumable that you will have to replace on a regular basis anyway, and spending a little bit of extra money and a few minutes researching your options will pay huge dividends. Even stock calipers and rotors can be inexpensively upgraded with a change to a performance pad compound, and there are multiple companies making drop-in replacements for pretty much every interesting car built in the last 30 years. Characteristics like cold coefficient of friction, initial “bite,” and resistance to fade are all customizable with off-the-shelf pads using different friction material. For optimum results, new stock or stock-replacement rotors properly bedded in using the pad manufacturer’s instructions are the way to go. But even if you forego replacing rotors and just clean and scuff the still-serviceable discs you have now, it will make a world of difference in brake performance.

An honorable mention here goes to flushing the brake system with new fluid, a proper bleed job, and even an upgrade to inexpensive but still DOT-approved braided stainless brake lines that won’t balloon under pressure to replace the worn out factory rubber ones.

Seat Belts

Here’s another mod that’s relatively inexpensive but pays big. Proper restraints, fastened and adjusted correctly, eliminate the steering wheel isometrics and knee-wedging that we end up doing unconsciously to remain in position during cornering and braking. Factory seatbelts are designed for comfort (mostly to increase usage) and to work as part of the supplemental restraint system in a crash, with belt pre-tensioners, precise attachment point geometry, and even sections of belt designed to stretch or extend via sacrificial stitching. None of this actually helps you prior to the rapid unplanned deceleration, however. Options here include SFI-style racing harnesses in 4 or 5 point configurations, and aftermarket belts designed specifically for the street, some of which even have DOT approval. Keep in mind, however, that just like removing and replacing a factory airbag-equipped steering wheel, you are defeating a safety device and the potential consequences are on you and you alone.

Here’s a completely free “mod” for cars with seatbelts that have a solid connection at the base of the B-pillar and a belt that passes through a slotted buckle before continuing to a retractor at the shoulder: Push yourself firmly back into the seat in the position you want to be in, run the waist part of the belt across your body while taking out any slack, and put a twist in the belt before clicking the buckle into place. It may take a few tries to get it the way you want it, but ‘free’ is the best price of all, and a snug fit across the waist will get you some of the advantages of costly race harnesses in terms of resisting side g loads with no real downside in safety. 

Sway Bars and Bushings

Sure, you might have a full set of double-adjustable coilovers on your wish list, but in terms of making a difference you can really feel, replacing the worn-out bushings in your factory anti-roll bar mounts and end links is incredibly cheap and rewarding. If you can stretch your budget just a little bit, stiffer bars (or even adding a rear bar to a car not factory equipped with one) will also radically improve handling. The best part is that as long as you stick with polyurethane bushings and don’t make the mistake of running solid bearings and heim joints on the street, it’s another mod with no downside to your car’s practicality for daily driving. Just be aware that factory anti-roll bars are calibrated to provide understeer at the limit on purpose, and making wholesale changes with roll stiffness can do unpleasant things to even the tamest car’s cornering balance. Pay attention to what the bar manufacturer recommends to steer clear (pun intended) of this issue. 

Preparation Matters

The Driver Mod

What’s something that only costs a modest amount, never wears out, and will make any car you drive for the rest of your life quicker? The legendary “driver mod,” of course! While this is often talked about in the context of a weekend bombing around the track at a race driving school, it doesn’t have to be that complicated and expensive if you live within reasonable distance of a local autocross venue. The Sports Car Club of America (SCCA) is probably the best-known national group that organizes these parking lot events, but there are plenty of other opportunities as well, from big car shows to brand-specific clubs. For a few bucks, you’ll get to test yourself and your car in a controlled environment and learn where the limits are without worrying about exceeding them. Many events will even provide experienced drivers to coach first-timers from the passenger seat, and if you really want a humbling experience, switch places and let them show you just how much faster your car is with somebody behind the wheel who really knows what they are doing.

Preflight Check

Here’s another not-mod that you really shouldn’t skip, for obvious reasons. Before you head out to the twisties, take just a moment to make sure your fluid levels are ok, nothing’s coming out from where it shouldn’t be, tire pressures are correct, and all the random junk in your back seat is left at home just in case. Grab the top of each of your front tires (or as close to it as you can, for those with sick stance and zero fender gap) and give them a nice hard wiggle to check for wheel bearings ready to give out or slop in the steering rack. Yes, it sucks to have to cancel your weekend fun because there’s something that needs attention, but it sucks a lot less than dropping a ball joint mid-corner and having to pay for a tow from way out in the boonies. 

Pre-run It

Even if the road is one you’ve driven a thousand times before, and you know every apex and straight, conditions change. While it might not be very exciting, prerunning your route at a leisurely pace before returning along it at a more spirited clip will let you find things like oil, coolant, water, rock slides, and even the occasional car on its roof (obviously driven by somebody who hasn’t read this article) with plenty of room to avoid them. It goes without saying that this is also a good way to gauge the current law enforcement level of interest on that road as well. More importantly though, this will significantly reduce the chance that you’ll yeet yourself off a cliff and into the afterlife because you only discovered an obstacle or puddle of oil once you got up close and personal with it. 

It goes without saying that this is also a good way to gauge the current law enforcement level of interest on that road as well…

We’ll end with one last thought – keeping a low profile and being respectful of other road users is extremely important. Nobody likes having a car in a ditch in front of their house every weekend, and loud exhausts, screeching tires, and aggressive driving in normal traffic lead to increased traffic enforcement or even nastiness like rumble strips and speed bumps. Enjoy the drive, but don’t be the reason things get ruined for everyone else.

The Big Squeeze: High Compression vs. Low Compression

One of the defining characteristics of an engine is the compression ratio, which in simple terms is a comparison between how much volume there is inside the cylinder when the piston is at its highest and lowest points (don’t get me started on Wankel rotaries – they’re basically witchcraft). Compression ratio interacts with a lot of other factors to produce power, and can be changed to some extent by selecting different components for the same basic engine during the build. To add another plot twist, the mathematically-calculated static compression of a particular combination can differ significantly from the engine’s dynamic compression in operation, thanks to sophisticated intake and exhaust design, forced induction, or even EGR (exhaust gas recirculation). 

A Real World Application for High School Geometry

To start calculation compression ratio, you need to know an individual cylinder’s displacement. This is the area of the cylinder multiplied by the length of the crank stroke. But you’re not done yet, because you also have to know how much space there is in the cylinder head with the piston all the way up as well. The difference between the maximum volume with the piston at bottom dead center and the minimum volume at the top is the compression ratio. This is, of course, a huge over-simplification, but it will give you an idea of what a number like “9.5:1” means – there is 9.5 times more volume inside the cylinder at BDC than there is at TDC.

Designs with long crank strokes relative to their bore diameters tend to also have high compression ratios. Diesel engines, which rely on very high compression to ignite the fuel and air mixture, are a typical example. But there are other factors that have a major impact on compression ratio. The design of the cylinder head’s combustion chamber is a big player here, as the smaller volume it incorporates, the higher the CR will be. Another significant way to alter compression ratio is through piston design – a ‘dished’ piston will have lower compression than a flat one, all other things being equal, and a domed one will have higher compression. Even things like the thickness of the gasket between the head and the block and whether the valves are dished will affect compression ratio.

Though it’s possible to math most of this out with a little applied geometry (or plug the appropriate numbers into an online calculator like a lazy internet tech writer would), the volume numbers for the piston and the cylinder head have to be actually measured, if they’ve been altered in any way from how the manufacturer delivered them. A head that has been “decked” by having material removed from the surface that contacts the block will have a higher static compression than an unaltered head, and pistons can be milled to lower compression, either on purpose or as a side effect of cutting pockets for larger diameter valves. While measuring actual piston dish/dome volume is kind of a pain, doing the same for a combustion chamber is actually quite easy, only requiring a measuring device with accurate markings in cubic centimeters, a piece of clear plastic with a hole drilled in it, some tinted water, and a bit of grease to seal the valves and where the plastic covers the combustion chamber. 

Compression Consequences

Now that we’re solid on what static compression ratio is, let’s take a moment to discuss why it’s important. In general terms, high compression (which is a relative term itself) is desirable because it enables more power production. Each cylinder-full of air/fuel mixture will have more room to expand and do work, making the engine more efficient. As mentioned before, diesel engines take advantage of very high compression to operate very efficiently compared to gasoline engines. But the same thing that makes diesels work in the first place – compression ignition – is also a big limiting factor for how much compression ratio a gas-powered engine will safely tolerate. 

In general terms, high compression (which is a relative term itself) is desirable because it enables more power production. Each cylinder-full of air/fuel mixture will have more room to expand and do work, making the engine more efficient…

120 or so years ago at the dawn of the automobile, engines were typically very low-compression compared to modern designs. The Ford Model T had a 2.9 liter inline four cylinder engine that produced a whopping 20 horsepower with a compression ratio of just 3.98 to 1. While the power output wasn’t all that thrilling, the low compression was a necessity during that time period when fuel was of uncertain quality and highly variable octane rating (we’ll get to more on that in just a minute).

As oil companies began to create standards for pump gas, compression rose to take advantage of better fuel, and the Second World War really turned up the wick on engine design. Because of ‘high test’ fuel, naturally aspirated engines for trucks, tanks, and especially aircraft became lighter and more powerful, and turbo and supercharged engines were finally practical. Even so, after the war when the first small block Chevy V8 engines were introduced in 1955, they ran compression ratios as low as 8.2:1 for durability. 

No-Knock Entry

The limiting factor on how much compression an engine can run is the knock-resistance of the fuel, commonly referred to as the octane rating. It gets its name based on a comparison of how hard it is to ignite relative to pure octane, a specific hydrocarbon fuel – gasoline rated at 93 octane in a particular test is easier, while 100 is comparable and 110 is more difficult. You’ll sometimes hear people say that what happens inside a cylinder is an “explosion” but if that’s what is happening, something has gone terribly wrong. It’s actually a ‘deflagration’ – rapid, but controlled burning. When fuel is compressed too much, it will spontaneously ignite and lead to preignition, detonation, or simply knock. Whatever you call it, it has the potential to very quickly melt spark plug electrodes, burn holes in piston tops, break the ring lands off the sides of the piston, and push out head gaskets. None of these are desirable outcomes

The limiting factor on how much compression an engine can run is the knock-resistance of the fuel, commonly referred to as the octane rating…

It’s possible to compensate to a degree for lower-octane fuel by running less ignition timing, but that’s a compromise at best. Because it takes a non-zero amount of time for an engine to completely burn a cylinder of fuel, all but the lowest-RPM designs incorporate some amount of ignition advance, firing the spark plug before the piston reaches top dead center on the compression stroke. As the flame front moves away from the spark plug towards the edges of the combustion chamber, it compresses the remaining unburned fuel and air, and if it squeezes it too hard, it can spontaneously and nearly instantly ignite instead of a smooth burn. This is one example of the dynamic compression we mentioned earlier.

Every engine has an ignition timing “sweet spot” that produces the best power when it is fed fuel with sufficient knock resistance, but it can run successfully, though with lower performance, if the ignition timing is retarded to later in the compression stroke to keep peak pressure in the cylinder below the knock threshold. You’ll often see modern vehicles with manuals that advise “Premium fuel preferred – 87 octane minimum” because they have sensors that listen for knock and pull out timing if they’re fed Regular instead of Premium. They’ll make more power on high octane fuel not because the gas is more powerful, but because they can operate at their designed ignition timing settings.

VE Made EZ

Another source of increased dynamic compression comes from an engine’s volumetric efficiency, which is a way of expressing how completely the cylinder fills with a fresh charge of air and fuel on the intake stroke. A 500cc single cylinder engine that ingests exactly 500 cubic centimeters of air per cycle is running at 100% VE, for example. Now, if you were raised to respect the laws of thermodynamics, you’re probably saying, “no mechanical system is 100 percent efficient!” and you are absolutely right, but there’s an interesting caveat. While the restrictions posed by the intake tract do indeed cause naturally-aspirated engines to normally operate below 100% VE, very clever engineering can allow an all-motor design to achieve over 100 percent under certain specific operating conditions.

This is possible because air, while not being very dense, does have mass, and moving mass has inertia. Careful design of the intake and exhaust manifolds, combined with specific valve timing, can take advantage of positive and negative pressure pulses reflected through the system in a narrow RPM range to ‘internally supercharge’ the engine and push VE over 100%. Though this was once confined to racing powerplants, increasingly sophisticated factory designs with variable valve timing and lift and variable intake geometry have made this effect worthwhile for mass production.

The net result of pushing VE over 100 percent is that the total compression ratio the engine experiences can be higher than the calculated static CR. Taken to the extreme, adding boost in the form of turbocharging or supercharging throws even more dynamic compression into the mix. Careful tradeoffs have to be made with forced induction engines to balance out the effect of boost with reduced static compression in order to keep detonation at bay – the efficiency lost by running lower compression ratios is more than offset by the increased power offered by intake pressurization. 

Approaching the Limit

Modern engine designs have seen compression ratio increased across the board, even for factory forced induction, and this is largely thanks to a much better understanding of what happens inside the combustion chamber during a power stroke. One look at a current engine’s piston and combustion chamber design will show you just how far technology has come from the days when the two-valve hemi head, with its combustion space shaped like half an orange peel, was the state of the art. Features like ‘squish bands,’ swirl-inducing peaks and valleys, and stratified charge strategies allow today’s engines to run compression ratios that would make those of just 20 years ago go ‘pop’ on the very same fuel. By figuring out what it takes to create a margin of safety for the knock threshold but still increase compression ratio, engineers continue to squeeze (pun intended) more and more out of every cubic inch of displacement. 

The Differential Difference

Adding the Right Traction to Your 4WD Truck

Before we dive right into how to turn up your truck’s traction ability, let’s first ponder a question that should be answered honestly. How do you anticipate driving your truck? Will it spend most of its time on the road, and will the off-roading you do plan on doing be mostly on gravel or compacted dirt? Will you be doing any driving on icy, snowy or wet conditions on pretty advanced off-road terrain? Do you anticipate driving through trails where very uneven ground, rocks and other obstacles and holes will be present? Taking these questions into consideration will greatly impact your decision-making when looking to upgrade your truck’s differential system(s). 

If you answered ‘yes’ to the first question above—congratulations! If you plan on sticking to mostly streets and highways or surfaces that are hard but not technically paved stretches of land, you really don’t have to worry about messing with your truck’s factory-equipped open differential, which is great. We understand the temptation to buy new parts is hard to fight off sometimes, but consider this a win and save yourself some time and money, and enjoy your truck as-is. 

We understand the temptation to buy new parts is hard to fight off sometimes, but consider this a win and save yourself some time and money, and enjoy your truck as-is…

For those who answered ‘yes’ to the second and/or third questions with the anticipation of driving through surfaces impacted by inclement weather that also feature more severe terrain, then you might want to consider shopping around for limited-slip or locking differentials. There are plenty out there to choose from, and it is best to still keep your personal driving scenario in mind when wading through these waters. 

Now, also keep in mind that whichever type of traction-adding components you choose will have a direct effect on different types of driving, wherein lies the importance of staying true to what you will actually be using your truck for. Bragging about having the latest, greatest, most expensive performance gadget on the market won’t do you a lick of good if it’s not used correctly, so do pay attention and choose wisely. 

Bragging about having the latest, greatest, most expensive performance gadget on the market won’t do you a lick of good if it’s not used correctly, so do pay attention and choose wisely…

Most light off-road duty adventures will be greatly improved with a rear limited slip differential, or better yet both a rear and front limited slip. These are the most widely used and common types of diffs since they cover such a wide application spectrum. What the limited slip does is shift a percentage of the torque to the wheel that has the most traction while limiting the slip on the wheel experiencing the least amount of traction (the one that is stuck in the air or free spinning on a patch of black ice). Torque is not always balanced between the wheels here, which will allow your truck to power through less than ideal surface situations with less of a chance of getting stuck. Icy, wet or uneven ground will pose less of a threat with the limited slip differential, so if you plan on encountering any of these foes on a regular basis, this traction-adding upgrade will definitely be money well spent. 

A locking differential will take your rig further than any limited slip setup can—no question. Now, do you absolutely, positively need to install a locker? Well, that all depends on if you want the power of a true 4×4, which means that all four wheels are getting power to the ground. Anything less than that might very well leave you stranded when attempting to take on some serious mud pits or extremely rough country. If you still plan on driving your truck on regular surface streets when you’re done on the trail, you’ll want to look into selectable lockers specifically. This will allow your truck to fire on all 4 wheels while off-roading, while still having the ability to flip back to an open or standard (stock) diff configuration with the flip of a switch. You’ll be able to beat the piss out of it off road, and still actually be able to drive it comfortably on surface streets just like normal. 

Within the realms of limited slip and locking differentials are other options to consider, naturally. There isn’t one system out there that can meet the demand of every driver of every truck for all conditions, so don’t get your hopes up. If you know and understand exactly what you’re asking of your truck, however, then you should already have a better idea of what side of the traction fence you’ll need to invest time and money into. The rest is merely addressing the details of personal preferences in order to fine-tune your driving experience. 

Top 10 Tools Every Off-Roader Should Carry

Tools are something that make everyday life possible. They come in a full range from “must haves” to “would be nice.” Some people would argue that all you need is a credit card, and a satellite phone. Most of us would rather help ourselves than call for help. The better your tools, the easier difficult tasks can become; especially when working on vehicles. Even simple tasks can become impossible if you don’t have the right tools. So what do you need as an off-roader? Let’s take a look at the basics. 

Most of us would rather help ourselves than call for help…

1. Socket Wrench

Flat tires happen. One of the most often required, and useful tools you can carry is a wrench that can remove or replace lug nuts. There are many options available from a straight breaker bar, to the latest battery powered impact guns that are on the market. If you can’t remove a wheel, a simple predicament can leave you stranded. It’s also wise to carry several different sizes of sockets so you can have what you need when the time comes.

2. A Jack

This one goes with the lug wrench; a good jack. There are countless uses for a lifting device when you go in the dirt. They are needed to change flat tires, get unstuck, or fixing bent tie rods or suspension links. High-lift jacks are popular because they can do several tasks. Just make sure you know how to use it, and have good jacking points on your vehicle. If you don’t have solid jacking points that mounts to the frame, and also allow clearance around the body panels, you won’t even be able to use one. Good jacking points are heavy duty bumpers, sliders, and the wheel lifting straps available. Other options are manual scissor jacks, and hydraulic floor jacks. If you use a hydraulic floor jack, you will need something to place it on so it doesn’t sink into the dirt. A piece of plywood works, or you can get bolt on bases for this, or even specially made jacks.

3. Shovel

When you go off-road, you will get stuck; it’s inevitable. When you are stuck, it’s because you are impeded by something. That something is either dirt, mud, sand, rocks or snow. You don’t want to be removing any of that by hand. I learned my lesson when I went for a quick little drive in my CJ-7, and slid into a snow bank. I had to remove my license plate to use as a shovel. With a real shovel, I would have been done in 20 minutes. Instead it took hours. A shovel can be used for many other things as well; putting out camp fires, trail repairs, burying a tire for an anchor point, etc. 

4. Jumper Cables

Like flat tires, dead batteries happen a lot. A jump start from or to another vehicle only takes a second if you have cables. If you don’t have them, your options are never good. You should not scrimp when it comes to your jumper cables. There are plenty of cheap cables out there that are not up to the task. Get some good heavy duty cables with copper wire, not aluminum. A good set will last you for years, and be reliable when you need them. Just don’t loan the out. 

5. Bailing Wire and/or Zip Ties

We are hard on our vehicles when we go off road. Things break, they come loose, and they get damaged. You need something that will hold things together until you can make permanent repairs. Zip ties are great, but they fall short when you need to hold up anything that gets hot like exhaust or brakes. Bailing wire is pliable enough to wrap around things, and it fits through bolt holes easily. When you double it up, it’s very strong. 

6. Vise Grips

Vise grips are a valuable tool because they perform many tasks. If you have a damaged bolt or are missing the correct size wrench or socket, vise grips will work. They clamp tight enough to hold things together securely. They can also be used for crimping electrical connectors, or capping brake lines. You can even get special vise grips with smooth jaws for crimping off fuel or brake lines without damaging them.

7. Tow Ropes and Ratchet Straps

Many of us carry a box filled with different tow ropes, and ratchet straps. Tow ropes are for pulling another vehicle. Ratchet straps are for securing things. Chains should be avoided. Chains are heavy for one thing, and they don’t give. Tow ropes are designed to stretch, and don’t release as much energy when they break so they are much safer. Don’t forget to also throw a tree saver strap in your box. Ratchet straps are useful for securing every type of loads. They can be used to hold down a spare tire, or secure a camper in the bed of your truck in an emergency. They are a very useful tool.

8. Fire Extinguisher

I have personally never needed a fire extinguisher, but have saved many people who did. This is one tool that you hope you will never need, but is a must have to carry. You also need to know how to care for your extinguisher. The types that have dry powder in them can settle over time. When you need them, the powder can be clumped in the bottom, and not discharge properly. Make it a habit to inspect your extinguisher before you go out to make sure it’s still charged, and give it a little shake to keep the contents dispersed.

9. A Tarp

A tarp is another item that is handy to have because it has multiple uses. We can’t always control where our vehicle breaks down, or where we will be working on it. Part of being safe in the outdoors is keeping your body free from injury. You only need to experience laying in cholla cactus spikes, sharp rocks, or hot pavement once to realize the necessity of having a good tarp to lie on. It can also be used to keep you dry in the rain, or cool in the sun. You can drape it over your winch line to absorb the energy if it breaks. You can carry water with it. You can use it to wrap up dirty items that have to go inside your vehicle. How many of you have slept inside your truck bed with a shredded tire next to you? A tarp is handy for many things.

10. A Buddy

Two minds are better than one, but so are two trucks, two sets of tools, two jacks, you name it. Traveling alone is something we all do out of necessity, but when it comes to being prepared off-road, you can’t beat having someone else along. When something breaks down, or you experience some other setback, it’s always good to have someone else to throw ideas around, help out with repairs, or just give you a sense of calm that everything will work out. They are also great for re-telling the stories of your great trail fixes and ingenuity used to get back home.   

Layin’ Frame

Some Basics On Slamming Your Ride

So you want to go low, huh? Ok, well there’s “just a few inches” low and then there’s “pavement pounding” low. Both are cool and have their place on certain vehicles, and while a modest drop in suspension does go a long way in terms of appearance, nothing compares to laying your car or truck out on the ground. Granted, there is quite a lot more to take into consideration if you’re interested in the latter option, but if you’re serious about taking your daily or show vehicle to the next level, it can be done, no matter what you’re driving. 

Asses the Situation

All vehicles are different, which means that the modification process to get said vehicle on the ground varies as well, as does the list of parts needed. Clearance plays a big role, especially with modern cars. With only so much available space at the front and rear, you may just have to get creative and pay close attention to tire selection as well as important wheel specs (width, offset, etc.). Every half of an inch counts, so do be sure to examine just which parts and pieces will need to be trimmed, relocated or cut out altogether in order to clear a path for adequate suspension travel. Classic cars in general have lots more room to work with at both ends, so take that in mind when deciding how to move forward with your project. 

Trucks, on the other hand have much more clearance space to play with at the rear. With only a bed floor standing in the way of axle and chassis clearance, there are just so many more options. Chopping up the bed is a necessity when ‘bagging a truck, with the easiest solution being to either cut out a portion of the floor that’s in the way, essentially. From there, you’ll have to decide to leave the area exposed, build a covered “bridge” or raise the entire floor up to keep a “stock” appearance. There are lots of ways to get the rear down on the ground with a truck, which makes this particular scenario mighty interesting. 

Equipment

If you’ve never ‘bagged any of your vehicles before, there are a few key components you’ll have to familiarize yourself with while prepping your ride for lower lows. Assuming that you will be ‘bagging your car or truck since hydraulic setups aren’t all too common these days (but they are out there), the air system is only as complicated as you make it. Air management systems have come a long way since the days of having to individually piece every single component out when building an entire air setup. 

The airbag itself is an essential component of the system, but it is not the most important (or even the most expensive). You’re going to find out quick that quality air management systems are worth every buck, as many of them have all the system’s ECU, valve manifold, and pressure and height control (in some premium packages) all built right into a small and convenient, easy-to-mount unit. From there, you’ll need to select an air compressor (or two) to keep the system supplied with enough air at all times. Figuring out air line plumbing can be a tedious process, but one that can still allow for creativity. Once everything is wired up and checked for problems, accessing this orchestration of components is made simple though a programmable controller, or if equipped, an app installed on your phone. 

The airbag itself is an essential component of the system, but it is not the most important (or even the most expensive)…

While that does sound like quite a bit to worry about, it is—to an extent. There used to be much more involved, but there are lots of plug-n-play type units that helps simplify installation. 

Alterations

Cutting and altering the chassis and other factory components (depending on the vehicle) is essential when it comes to “laying frame”. While it’s a big step to take, it’s important to not take these steps lightly, and ensure that an experienced person take the lead, even when it comes to simple rear frame notches. Using a plasma cutter, cut wheel and drill all require some know-how to deliver the best results (which includes your safety). Always remember the golden rule when working with these tools—measure twice and cut only once!

Half and Full Frame Packages

A lot of classic muscle car and truck projects have the luxury of a wide selection of well-crafted front, back and full chassis systems on the aftermarket. These take a lot of guesswork out of building the best air ride setup possible. Since the existing frame on vehicles of a certain age can be “iffy” at best, selecting these options could really come in clutch. These types of setups do offer far more than the ability to go up and down, as optimum ride quality is the ultimate objective with these, which will only make your project better in the long run. These kits do run on the high side when it comes to suspension components, but they are definitely worth the dough. 

‘Bagging your ride is a big step, that’s for sure, but once it’s done and all the kinks are worked out, it really is worth the effort. Nothing gets more attention on the road than a car or truck that can change the height of their ride with a simple push of a button. Even at rest, there’s nothing quite as cool as a vehicle resting on the ground with the wheels and tires tucked far into the fenders. Your ride will definitely catch all the attention in the parking lots at work, at the grocery store, as well as at any car show you take it to. 

Nothing gets more attention on the road than a car or truck that can change the height of their ride with a simple push of a button…

Don’t fall into the trap of investing only the minimal amounts of money and time when slamming your vehicle. You definitely get what you pay for as far as parts and components go, and there is no such thing as “cheap” quality labor (unless you’re doing the work or have a friend or relative willing to help out).

Getting Ratio’ed

The Importance of Power to Weight

How do bees get airborne? How do hummingbirds gracefully hover? How do helicopters chase you out of your favorite spot at 2:30 on a Sunday morning with that stupidly-bright spotlight? Lots of power moving as little weight as possible. 

Horsepower to the tires has big implications for automotive performance, but like everything else about going fast, it’s not about one number. What’s more important is how many pounds each horsepower has to move around, and the overall power-to-weight ratio is the real determiner of more than just how quickly a car accelerates. Today, we’re going to talk about some things you might not have considered before when thinking about how much power you need to achieve your performance goals, or on the flip side, how light your car has to be with the horsepower you currently have.

What’s more important is how many pounds each horsepower has to move around…

Defining Terms

Power to weight ratio is just what it sounds like – how much power is available, compared to the mass of the vehicle. You can express it in any unit of measure you prefer; our European friends will like kilowatts and kilograms, but US readers will probably find it easier to relate to how many pounds each pony has to carry around, so that’s what we will stick to here. To give you some perspective, here are a few examples of production car power to weight ratios, based on factory figures:

• Toyota Prius (2022): 121 HP (net power), 3,010 pounds curb weight = 24.9 pounds per HP
• Honda CRX Si (1987) 91 HP, 1,953 pound curb weight = 21.5 pounds per HP
• Mazda Miata (1997): 129 HP, 2,180 pound curb weight = 16.9 pounds per HP
• Dodge Challenger SXT V6 (2021): 303 HP, 3,858 pound curb weight = 12.7 pounds per HP
• Honda S2000 Club Racer (2008): 237 HP, 2,765 pounds curb weight = 11.7 pounds per HP
• Acura NSX Type R (1992): 270 HP, 2,712 pound curb weight = 10.0 pounds per HP
• Chevrolet Corvette 1LT Z51 (2021): 495 HP, 3,366 pound curb weight = 6.8 pounds per HP
• Dodge Challenger SRT Super Stock (2021): 808 HP, 4,429 pound curb weight = 5.5 pounds per HP

Just for fun, let’s throw in a couple of fairly tame sportbikes:

• Kawasaki Ninja 400 (2022): 45 HP, 541 pounds curb weight (includes 175 lb rider) = 12.0 pounds per HP
• Kawasaki Ninja 650 (2022): 67 HP, 598 pounds curb weight (includes 175 lb rider) = 8.9 pounds per HP

We can draw some initial observations from these examples right away. First of all, the two motorcycles shown are generally considered pretty weak sauce by two-wheel standards, but they are still in a totally different realm than most cars. Second, there are some cars we’d all consider “fun to drive” that don’t have very good power to weight ratios – more on that in a minute. Finally, the top of our list has a Challenger model that is an absolute whale, but thanks to an equally gargantuan engine, is in a class of its own in terms of power to weight.

The point to be made here is that cars (and motorcycles) that are lighter in absolute terms tend to be more enjoyable for enthusiasts even if they are only middle-of-the-pack in horsepower. That’s because weight, or more correctly mass, affects more than just straight-line acceleration. 

Massive Implications

Because inertia applies in all directions, not just to acceleration, with all other factors being equal a car that weighs less overall will need less tire, less suspension, and less brakes to achieve the same results as a heavier but more powerful one with the same power to weight ratio. Conversely, better tires, suspension, and brakes will be more advantageous on the lighter car as well. 

As time has passed, increased safety requirements for side impact air bags, crush zones, and a hundred other advances, combined with customer demand for things like heated power-adjustable seats and Bluetooth-connected in-car entertainment systems have inexorably pushed curb weight up, even for cars built to be lightweight. The 2014 5th Gen Camaro Z/28 is a good example, being available without air conditioning or a stereo, but the need to incorporate government-mandated audio feedback for turn signals, seat belt warnings, and whatnot meant that it still had to have at least one speaker.

So far, though, the increase in curb weight of the average car has been more than offset by the increase in average horsepower. But it also means more capable (and more expensive) suspension, tires, and brakes are required. It’s also often said that “light costs money” and that’s very true when you are trying to achieve the same results with less weight, like substituting an aluminum block of comparable strength for a cast iron block in the same engine design. On the extreme end, carbon fiber body panels, aluminum frames, and other semi-exotic materials and manufacturing methods can be employed by the factory.

Simplicate and Add Lightness

Fortunately, even if you’re on an instant ramen budget and spending a ton of money on featherweight aftermarket parts isn’t in the cards, all is not lost. Manual cloth seats from a base model car can replace the seven-way heated leather ones you have, for example, and you may even end up money ahead by selling them to some would-be baller looking to upgrade. AC deletes, while trending toward the hardcore end of the spectrum, are typically good for some significant weight savings, and if you still want to keep cool and not make your own gravy while sweating out the summer, we bet that without even trying too hard the typical enthusiast could find at least 20 pounds of loose junk in the car that you have been Ubering around for free. Those passenger seats sitting in the pits at the local autocross or dragstrip grudge night take zero dollars to do, and they give you a place to sit and hang out with your friends in comfort while you wait for your run group.

Fortunately, even if you’re on an instant ramen budget and spending a ton of money on featherweight aftermarket parts isn’t in the cards, all is not lost…

There’s something really satisfying about making your car faster without adding a single pony under the hood, and all it takes is a little bit of imagination and some elbow grease. As a bonus, you’ll be able to corner harder and brake later – sure, it’s not as sexy as putting on a turbo or jetting up the nitrous, but it’s a tried and true speed not-so-secret. 

Mid Travel vs. Long Travel Off-Road Suspension

Which Is Right For You?

Every truck and its owner are different. While that may sound like stating the obvious, it is very much true, and determines the relationship of how someone drives their pickup. Most folks are more than fine with leaving their truck bone stock, and hardly ever venture far from paved roads. Modern trucks are easy to drive, and are often treated as a regular car—with a handy bed that comes in clutch during those sporadic trips to Home Depot. While this picture comes off as being dramatically domesticated, it’s really not that far off from how it really is, except for the truck owners that have a sharp taste for far more action and adventure. 

Now, the type of action we have in mind here is off-road adventure, and what exactly that means to each individual truck owner. While a good percentage of them tend to lean toward the mild side of things (which isn’t a bad thing at all) there are a slimmer number of truck fiends that crave the most capable, unstoppable setup imaginable. Of course, we’re talking about the timeless debate between mid- and long travel truck suspension systems, and what it really means to build and drive them. 

The Deciding Factor(s)

Which is the right one for you? Well, only you can really answer that question. There’s a lot to take into consideration—some are the obvious cost and labor issues, and others may be less glaring and require careful attention. You’ll have to seriously address the pros and cons of how mid- and long travel suspension systems stand to benefit your particular situation and how they could possibly negatively affect you world as well. 

Materials

While there is no real “negative” surrounding either of these suspension upgrades as they are both far superior than factory specs if you plan on doing any type of off-roading—even in the slightest. Mid-travel setups are far more accessible than their long-travel counterparts, as most basic front kits consist of at least an aftermarket uni-ball upper control arm, a quality coilover with reservoir, an upgraded leaf spring pack, axle flip kit, and a reservoir-equipped shock. All are fairly straightforward to install, and all of these components bolt right into place. 

Mid-travel setups are far more accessible than their long-travel counterparts…

On the other end, long travel setups are far more involved as you’re looking at aftermarket upper AND lower uni-ball control arms, an extended axle shaft, tie rod extension, coilovers with reservoir, and strategic weld-in reinforcements in the way of braces/gussets for optimum strength. You’ll see a beefier leaf spring pack here at the rear, which will be placed underneath the axle. This means that bolting on shocks in their factory mounting points will not be possible. You’ll have to get creative here to make it work, whether that means relocating the mounts somewhere else of going right through the bed utilizing a bed cage. Don’t expect things to be as easy as with mid travel setups here, it’s far more work, but there is a larger payout here once the dust settles. 

Cost

Long travel suspensions cost much more to build, obviously, but in more ways than you might think. Aside from the suspension components themselves, you’ll also have to take factory fender panels out of the equation, and think about wider, fiberglass options instead since the width of the front suspension is extended and the rear travel is extended so much over stock. On the bright side, you’ll be able to run comfortably with 35” tires without having to endlessly cut and trim until there’s nothing left of those original fenders anyway. 

Type of Driving

Think of mid travel suspension good for casual trail cruising, some moderate rock climbing, and increased general access to rougher conditions that wouldn’t otherwise be comfortable in a stock truck. You’ll have a lot more options open to you as far as terrain you’ll be able to take on, but take those options and multiply them—that is the true capability of long travel. But is long travel feasible for daily driving duties? Sure, why not? It’s really a personal preference with the additional width up front and all, but it’s just like anything else, you’ll adapt. 

Bottom Line Pros and Cons

Let’s start with mid travel first. You’ll be able to install the suspension components comfortably at home without any specialty skills or tools. The parts involved are fewer and relatively inexpensive, and you’ll still be able to upgrade tire size—think 33s without having to cut/trim fender wells too extensively. While you’ll be able to comfortable drive your truck daily and still have more confidence off-road, you will still be limited to more extreme conditions that only a long travel will be able to handle.

Long travel suspension parts do add up fast and installation isn’t always for the everyday DIY builder at times. You’ll most likely have to do some welding, so if you don’t have this skillset under your belt, you may have to outsource or wrangle a buddy who can help out. Save part of your budget for replacement fender panels, and prepare to lose valuable bed space for that bed cage and probably a spot to throw your spare. Don’t let all those factors stop you from seeing the job through—once everything is done, the off-road landscape will be your oyster. 

…once everything is done, the off-road landscape will be your oyster…

In the end, you’ll have to make the decision of just which scenario is right for you. Are you down for the higher cost and more in-depth installation of the long travel? Is it really worth the extra money and extra headaches? Are you fine with still being able to having more paths opened to you while still being limited to only where long travel-equipped trucks can travel? Weight it all out, sleep on it, talk it over with your better half, and then start building the truck that is right for your own personal situation. 

Ten Euro Standouts

The Most Influential US Imports from the Old World

After the end of the Second World War, America emerged unchallenged in terms of manufacturing and industry. All the domestic car companies who had turned their might to supply the “Arsenal of Democracy” were quickly pivoting back to products designed to fill pent-up civilian demand. And yet, in Europe just as in Asia, war-ravaged economies saw the US domestic market as a way to jump-start their own reconstruction, despite formidable barriers. 

…war-ravaged economies saw the US domestic market as a way to jump-start their own reconstruction, despite formidable barriers…

For the next five decades, German, Italian, English, and French manufacturers worked to solve the puzzle of selling stateside. While there were many misfires and failed attempts along the way, we also received a lot of cars that stood out for their innovation, performance, or just plain lovable weirdness. These weren’t the Porsche and Ferrari sports cars, but often very ordinary designs that rose to greatness. Here’s ten Euro cars that all made their mark on the United States, for a lot of very different reasons. 

1949 – Volkswagen Beetle

A literal “people’s car” designed for a dystopia that thankfully never fully came to be, the Volkswagen Type 1 finaly reached mass production just in time to help a shattered Germany get back on its feet. It went on to see more than 21 million cars sold worldwide over its very long production run, and although it started out as underpowered and unsophisticated even by 1930s standards, the Bug went places nobody could have imagined. In every form of motorsports from road courses to drag strips to Baja, the VW was embraced and found success. In the driveway, it taught Boomers to wrench without fear (and how to drive stick – once you master a VW transmission, everything else is cake), and it’s pretty safe to say that as long as there is gas to burn, somebody will be turning out new air-cooled flat-fours for them.

1960 – Austin Mini

Not everyone knows that the UK spent almost ten years after WWII with rationing of certain items still in effect – the war had taken a high toll in manufacturing infrastructure and massively disrupted public transportation. Against that backdrop, the Austin Mini debuted in 1959 and a year later, left-hand-drive versions began export to the US. While the total numbers that made it to our shores weren’t spectacular (approximately 10,000 over seven years), the impact they had is hard to understate. Here was the first widely-available transverse engine front wheel drive economy car most people ever experienced, and its space-efficient two-box profile and drivetrain layout set the standard for tens of millions of cars from dozens of makers in the subsequent years. 

1968 – Fiat 124 Spider

Designed by Pininfarina, the little convertible Fiat somehow managed to be an Italian sports car in the same mold as England’s classic roadsters, but with ever-so-slightly better reliability. First appearing in the US in 1968, the model managed to soldier on all the way into the early 1980s, with upgrades in engine displacement along the way. Many say that the Mazda Miata was an homage to those English roadsters, but the commercial success of the Fiat Spider made it a more direct ancestor (even if it wasn’t good enough to keep the company in the US market.)

1974 – Fiat X1/9

This toon town caricature of Italy’s vaunted mid-rear-engine exotics never made more than 75 horsepower from the factory, was undrivable by anyone taller than six feet, and was abandoned by its parent company in 1982 to be picked up by Bertone and limp on in the US (the car’s largest market by far) through 1987. It was also a riot to drive, and foreshadowed the MR2 and even the Fiero as an affordable mid-rear two-seater.

1982 – BMW E30

It’s not throwing shade on BMW to call the E30 3-series their version of the Civic. It revived the market formerly served by the classic 2002 for enthusiasts who wanted a compact car that was fun to drive and affordable. In the secondary market, it became a tuner superstar thanks to its easy availability and the fact that all the fundamentals were done right. 

1983 – Audi Quattro

If you like the GT-R, EVO, and WRX STi, you can thank (at least in part) Audi for blazing the trail. The original Quattro hit the US market at a time when the only other car with full-time AWD was the AMC Eagle. While the Eagle was special in its own way, it was no performance car, and the Audi’s turbocharged inline 5-cylinder and rally pedigree were something totally new in America. Though the first Quattro sold in miniscule numbers in the USDM, it was the vanguard of things to come worldwide.

1983 – Mercedes W201

Not to be outdone by their rivals at BMW, Mercedes jumped right into the compact market with the 190-series “baby Benz,” gifting the W201 chassis with a sophisticated suspension and a rev-happy inline four cylinder engine in various displacements. While it didn’t gain the same traction with street tuners in the US that the E30 did, it found great success in road racing worldwide and changed Americans’ conception of Mercedes as either Gullwings or diesel-powered living room couches to a viable performance brand.

1983 – Volkswagen Golf/Rabbit GTI

Though the VW Golf Mk1 arrived in the US in 1975 (and was called the Rabbit, for reasons which are not entirely clear) and overseas markets got the hot rod GTI version a year later, Americans would have to wait until 1983 to get a Rabbit GTI. While the 90 horsepower 1.8 liter engine (uprated to an even 100 for 1984) is nothing special by today’s standards, in the light and well-engineered Mk1 chassis it was a paradigm shift in economy car high performance. Looking back, the “hot hatch” category was inevitable, but Volkswagen got it right first, and created a legend that continues to this day.

1984 – Volvo 760T

Sure, the Volvo 122S/Amazon had European rally cred in the 60’s, and the P1800 looked exotic and cool to American eyes (and even had a star turn as Roger Moore’s ‘hero car’ in The Saint TV series), but by the mid-Eighties, the Swedish car-maker was known for safety and cars that could be accurately modeled with LEGO blocks. Then, in 1984 US buyers were offered the turbocharged 760T, which not only led to the widespread misuse of the word “intercooler” but more importantly gave us a quick, practical, and safe car with a bulletproof boosted RWD drivetrain. To this day, “turbo bricks” still have a small but very enthusiastic owner base in America.

1985 – Merkur XR4Ti

You knew you weren’t getting out of this without us throwing in at least one really weird one, and the Sierra XR4i from Ford’s European branch certainly checks that box. Rebadged and rebranded as the Merkur XR4Ti in America and sold through 800 or so Lincoln/Mercury dealers, you wouldn’t mistake one for anything else thanks to the ‘aero’ nose, biplane spoiler, and notch-profile 3-door hatchback body. The FR drivetrain layout was motivated by a 2.3l iron-block inline four topped by a turbo pushing 14 PSI – the same engine in the SVO Mustang and Thunderbird Turbo Coupe, minus the charge cooler, with 175 horsepower on tap in manual transmission cars. Ultimately, sales didn’t justify updating the model to meet increasingly tight safety regulations, and the strong Deutschmark didn’t help. The short-lived experiment left a bad taste with Ford US, and we wouldn’t see another Euro-manufactured model from the Blue Oval again until the Ford Focus RS arrived in 2016.

So there’s our list – we’ll admit that it’s subjective, and reasonable people can disagree over things like this. What USDM cars imported from Europe would you put on your own list of most influential models? 

What is VTEC?

How Honda Created a Legend With a 10mm Pin

What does it take for one specific bit of simple, yet brilliant technology to achieve meme status? In the case of Variable Valve Timing and Lift Electronic Control (better known as VTEC), it started out as a way for Honda to offer better performance while still meeting emissions standards and displacement limits at the start of the 90s and arguably gave the company’s automotive division the same kind of high tech street cred their motorcycles already enjoyed. 

The original VTEC led the way for a whole new slate of variable valve actuation systems from practically every major manufacturer, with a wide range of complexity and effectiveness seen today. Back in the day, it would be hard for anyone to imagine that a simple pin moved by a hydraulic actuator could become such a legend, but in retrospect it seems like one of those “why didn’t I think of that?” inventions.

Best of Both Worlds

To understand the impact of VTEC on the automotive world, it’s worthwhile knowing exactly what it is and what it isn’t. Conventional piston engines rely on one or more camshafts, turning at one-half engine speed, to control the motion of the intake and exhaust valves. No other single aspect of engine design has a bigger effect on performance, economy, or emissions than the timing and intensity (for lack of a better word) of valve events, and for engines without some sort of variable valve control, every compromise gets carved in steel at the factory and can’t be changed without getting into the ‘wet’ part of the engine. 

This is important because the physics involved in getting air and fuel into the cylinder and exhaust out mean that a cam lobe design optimized for low-end grunt is going to be unhappy at high RPM and vice versa. At lower speeds, cylinder-filling is improved by having relatively small valves with low lift, trading away some pumping losses in exchange for keeping velocity up in the intake tract, but towards the upper end of the RPM scale, bigger is better and low lift will kill airflow. Similar tradeoffs for valve duration (the part of the 720 degree four-stroke cycle when the valve is open to a meaningful extent) and valve overlap (degrees of crank rotation during which the exhaust valve is still closing while the intake valve starts to open at the end of one cycle and the beginning of the next) also have a big effect on how the engine delivers power. 

With a traditional camshaft, it’s one and done since whatever specifications were ground into the lobes at the factory are all you have to work with short of a swap. Hot rodders came up with some work-arounds, of course – part of the skill set of the traditional pushrod V8 racer was ‘degreeing the cam’ which involves using an adjustable timing gear set to move the cam’s timing earlier or later in the cycle, and dual overhead cam engines can use the same strategy plus change the intake and exhaust timing relative to one another to get some adjustability for overlap, but this was strictly something done in the shop rather than on the fly while the engine was running. More crucially, it didn’t change the cam lobes’ profile or lift.  

A Stroke of Genius

The solution seems obvious now, but at the time it required asking what sounds like a dumb question – “If the engine runs best with one cam design at low speed, and another at high speed, why not give it two cams?” At its core, that is all VTEC is – a way to put two completely different camshaft grinds into the same engine, and switch between them on demand. That’s much easier said than done, though, especially when whatever you come up with has to be simple enough to produce economically, durable enough to last for a hundred thousand miles or more, and designed to fail ‘gracefully’ and not leave you stranded if something goes wrong. 

… that is all VTEC is – a way to put two completely different camshaft grinds into the same engine, and switch between them on demand…

In 1984, Honda launched the New Concept Engine program with goals that included increasing torque and horsepower for their car engines across the RPM range, with an eventual benchmark of achieving 100 horsepower per liter of engine displacement for production engines. Initially, the NCE initiative led to powerplants like the DOHC ZC (forerunner of the D-series engine) as early as 1985, but the real breakthrough came when previous research begun in 1983 into a system intended to improve fuel economy was rolled into the new project. 

One of the main players in the NCE project was Ikuo Kajitani from Honda’s First Design Department in their Tochigi R&D Center. “Characteristically,” Kajitani said, “four-valve engines are known as high-revving, high-output machines. And for that reason we knew it would be quite difficult to achieve low-end performance if the engine’s displacement were too small.” He was certain that a solution to the problem could be found in the work done on the fuel economy project in the form of an engine that could change valve timing and lift dynamically during operation.

This capability took shape as a very simple but elegant system that uses only a few additional parts compared to a conventional valvetrain. At the beginning, the team had considered around thirty different methods of achieving this goal, but to narrow down the field, priority was given to systems that relied on proven technology rather than novel approaches that might have unforeseen show-stopping flaws. With a mixture of caution and optimism, ideas that seemed promising but had a high risk of being developmental dead-ends were set aside. One of the most important goals was to have a mechanism that could handle 400,000 cycles without failing. In the end, the team settled on the system we now know as the original VTEC.

For each cylinder, instead of a single cam lobe to control valve events, there would be three: Two low-speed lobes with a single high-speed lobe between them. With the system deactivated, each valve would be controlled by its own low-speed lobe, while a third cam follower with no direct connection to the valves followed the profile of the single high-speed lobe. On computer command, a hydraulic valve would send oil pressure to move a pin into place to connect the outer followers to the inner one and lock the whole assembly together, causing the valves to follow the more aggressive center cam lobe profile. 

No Magic Involved

Though the concept was simple, there were still significant technological hurdles to overcome. One major example of this was the fact that they needed to squeeze three lobes into the space originally occupied by one, and those lobes would also be operating the valvetrain under higher loads and engine speeds than they’d previously been engineered for. Solving this issue required improvements in both metallurgy and design, but the team achieved their goal (and then some) in time to confidently introduce the new technology for the 1989 model year. 

While VTEC in its original incarnation does allow an engine to operate in ways that a fixed valvetrain simply can’t, there’s a widely-held misconception that it’s some kind of super-science that works like hitting the switch on a nitrous system. In reality, what it did was allow Honda to build engines with the ability to change between a cam designed for efficient, clean, and fuel-sipping performance to one with the grind the engineers wanted to use in the first place. As a matter of fact, it’s not uncommon in race applications to use a single-grind camshaft that actually defeats VTEC in order to increase tolerance for abuse and reduce complexity and weight. When street driving isn’t high on your priority list, the flexibility and broad powerband that VTEC allows isn’t as important, but it makes a huge difference in your daily driver.

…it’s not uncommon in race applications to use a single-grind camshaft that actually defeats VTEC in order to increase tolerance for abuse and reduce complexity and weight…

The Bigger Picture

For all the popularity of “VTEC just kicked in” memes, the system actually does what it was intended to do – Allow small-displacement engines capable of high fuel economy and low emissions during test cycles and normal driving to also provide exceptional horsepower when run hard. In the process, Honda managed to turn cars like the Civic from quirky but reliable transportation devices into ones that were actually fun to drive fast. Whether it was their intention or not, you can argue that the evergreen popularity of all the generations of Civic that followed were a direct result of the NCE project and the development of VTEC. 

Today, every manufacturer has implemented some sort of variable valve timing setup, even for old-school pushrod V8 engine designs. There’s a veritable alphabet soup of acronyms used to describe all the different proprietary ways manufacturers have come up with to adjust valve timing, intake versus exhaust cam phasing, and so on, and Honda has gone on to improve their own engines with VTEC-E, 3-Stage VTEC, i-VTEC, and i-VTEC with Variable Cylinder Management. But the real special sauce – changing to a completely different cam profile on demand – remains at the core of VTEC technology. Until we reach a point where camless valve actuation via pneumatic or electronic direct control finally makes its way from the cost-is-no-concern pressure cooker of Formula One racing to the street, Honda’s approach will likely remain as the best way to change lift and duration on the fly. 

You Bought A New Track Car – Now What?

Essentials for Hot Laps on a 5k Budget

So you’ve taken the plunge and bought yourself a dedicated track car. You did your research, found what you were looking for in sound mechanical condition and not already so far from stock that you’d have to rip everything out before doing it the way it should have been done in the first place, and you’re eager to get it prepped and put some laps on it. But you’re not made of money, and your meme stocks only got you into low earth orbit instead of to the moon, so you have a $5,000 budget for everything you’re going to need. 

Some hard choices will have to be made, because every dollar spent in one area means a dollar less to spend somewhere else. Here’s how we would allocate those 50 Benjamins most effectively – while your priorities are going to vary from ours, having a plan is the difference between a car on the track and yard art on jackstands for another year because you ran out of money and motivation.

Helmet – $350 ($4,650 Remaining)

Yes, we know you already have a helmet you bought off Craigslist. Yes, we know you are the one driver who will never, ever crash. This is still non-negotiable. Every reputable track day event organizer will insist on an ‘in-date’ skid lid that meets an accepted testing standard. Most often this is Snell SA or its equivalent – some sanctions will accept a Snell M-rated helmet, but the DOT-only models are almost always not considered good enough, for a reason.

Helmets designed to meet the SA and similar ratings have features that make them better suited for automotive use, where sharp impacts with objects that can penetrate the shell are more likely than the types of forces involved in motorcycle crashes, and they’ll have a fire-resistant liner. The “in-date” part is important too; the impact-absorbing liner has a finite lifespan, which gets shorter the more it is exposed to temperature extremes or solvent and gasoline fumes. 

While it’s possible to get an open-face helmet that carries a SA2020 tag for as little as $160, we recommend a full-face model, and as the list price goes up you’ll also get better fit and finish and improved comfort, which is important when you’re trying to concentrate on-track. Throw in another $40 or so for a fire resistant head sock (also good for comfort, as well as keeping the liner of the helmet cleaner) and $350 is a reasonable starting point for this critically important item.

Tires/Wheels – $2000 ($2650 Remaining)

We’re assuming that if you’re limited to a $5k overall budget for track car upgrades, you’re probably not going to trailer to and from events. We’re also going to assume that you will want a separate set of wheels and tires so that you’re not burning through expensive high-performance tires daily driving on them (though mad props to you if you are hardcore like that – we’ve been there ourselves). Like everything else on this list, wheels aren’t an area where you want to cut corners, but it’s entirely possible to get into a set of four new, quality wheels from a reputable manufacturer for around a grand. For that price, you are looking at cast rather than forged wheels, so the tradeoff is slightly higher weight for a lower price, as well as not being as forgiving or repairable when tweaked during inevitable encounters with debris or curbs.

Like everything else on this list, wheels aren’t an area where you want to cut corners, but it’s entirely possible to get into a set of four new, quality wheels from a reputable manufacturer for around a grand…

Tires are consumables, and depending on how hard you run them and what your level of compromise is between grip and longevity, these may have to be replaced several times a season. Fortunately, it’s often possible to find a well-heeled fellow enthusiast who always has used tires that have ‘gone off’ for full-boogie competition purposes but still have plenty of laps left in them for less serious use, so we’re compromising and putting a cost of $250 a corner out there to give some wiggle room for that initial set. Like always, your experience may vary, and cars with uncommon fitments or really big meat will tend toward the more pricey end of the spectrum. 

Brake Upgrades – $1250 ($1400)

Here’s another area where there is a wide range of possibilities – if your track car has decent stock brakes, all that may be necessary for anything less than full competition use might be a change to a different brake compound, braided stainless flex lines, new rotors, and a fluid flush and bleed. On the other hand, most cars of interest to the track day crowd have a lot of bolt-on options at surprisingly reasonable prices. If you don’t go totally nuts, our budget should at least cover a front caliper upgrade in addition to the other things mentioned above, plus a spare set of pads to be bedded in and brought with you if you’ve chosen a soft-but-grippy compound and a tight course to run on for a mid-day swap.

if your track car has decent stock brakes, all that may be necessary for anything less than full competition use might be a change to a different brake compound, braided stainless flex lines, new rotors, and a fluid flush and bleed…

Suspension upgrades – $1400

We’re going to take the last of our remaining budget and allocate it toward suspension. On the less expensive end of the scale, a complete, properly engineered and matched set of quality replacement springs, dampers, anti-roll bars, and polyurethane bushings can set you back as little as $750, while the sky is the limit for a complete competition-spec coilover conversion with multi-way adjustable dampers. We’re splitting the difference here, but odds are you will come in either substantially above or below our average estimated price. Depending on what kind of tracks you prefer, you may prioritize suspension above brakes, or the other way around, and adjust your spending on these last two categories accordingly.

One thing you absolutely do not want to do under any circumstances is to cheap out here; there are a lot of janky ‘lowering kits’ and coilover conversion setups with suspiciously low price tags and brand names you have never heard of, but spending any money on components of dubious quality and unclear origin can only lead to disaster. 

That Money Went Fast…

As you can see, it doesn’t take a whole lot to blow through $5k getting your new toy set up properly, but going into it with clear expectations for the cost and effort involved can keep your dreams from dying before you ever get to the track. Keep in mind that this is just a start, and in order to keep your racing fun sustainable, it’s a good idea to set aside money for every event you attend in some place where you won’t spend it, to be used for future consumables like tires, brakes, and maintenance items. Budgeting is never fun, but it makes the fun stuff possible, and helps you to drive more and dream less. 

Hot Swaps

Engine And Chassis Combos Limited Only By Imagination

Engine swaps might seem like a recent thing, but OG hot rodders did it back in the 1950s, putting the then-new small block Chevy V8 into Ford Model T chassis, and when Cadillac created a long-stroke 500ci version of their corporate big block in 1970, wrecked Eldorados became a prime target for drag racers looking for as many cubes as they could get. Today, despite tightening regulations that threaten to make any kind of automotive modification illegal, let alone a complete motor swap, mixing and matching cars and drivetrains has never been more popular. Let’s look at some of the most common types of hybrid chassis and engine combinations (and we mean that in the cool way, not the electric motor ‘hybrid’ sense) and the reasons behind them.

All In The Family

In terms of sheer numbers of completed swaps, updating (or backdating, in some cases) a particular car with an engine from the same manufacturer takes the top position. In the import and sport compact world, the most common swaps involve upgrading Hondas with more powerful engines – the trend began with taking lightweight Civic or CRX shells originally equipped with fuel-sipping but low-output D-series four cylinder engines and replacing them with more powerful B-series engines from models higher up on the price and performance ladder. With the introduction of the even more powerful and versatile K-series, those became the donor engines of choice, despite being somewhat more complicated to swap due to the necessity of changing transmissions as well. The extra effort is worth it, though; 200 horsepower or more from a completely stock engine in a late-90’s Civic that tips the scales at under 2,400 pounds makes for very entertaining performance at an affordable price.

In terms of sheer numbers of completed swaps, updating (or backdating, in some cases) a particular car with an engine from the same manufacturer takes the top position…

Honda engine swaps have become so popular that you can find ready-made components like engine and transmission mounts, headers, and ECU adapters for pretty much any reasonable (and more than a few unreasonable) combination of engine and chassis. With the trailblazing handled, potential compatibility issues have all been sorted out by somebody somewhere. It just takes a bit of research to come up with a proven recipe to follow, and entire books have been written on the subject covering every last detail.

Another common form of swap involves putting an engine not available in the US market into a chassis that was sold here, with the first example that comes to mind being the Nissan 240SX. Known in Japan as the 180SX and Silvia, when the company brought this fun little RWD coupe to America, they decided to replace the JDM CA and SR series turbocharged engines with KA series naturally aspirated ones. This decision was likely based on the fact that the KA engines were already “federalized” for US emissions regulations and would be less expensive than bringing in a new powerplant without an existing approval. Though well-suited for mainstream buyers, since these engines had previously been used in Nissan’s Hardbody line, they were derided by some as ‘truck engines’ unworthy of the car’s sporty image.

Of course, enthusiasts care not for things such as EPA regulations, and many CA and SR engines got strapped to pallets in Japanese wrecking yards and shipped to the west coast to be reunited with S13 and S14 240SX models here. Some particularly ambitious souls went as far as to cram RB26DETT twin turbo inline sixes from the JDM Skyline GT-R (among other applications) into that chassis as well.

Speaking of legendary Japanese turbo sixes, let’s not forget the Toyota 2JZ-GTE. This engine powered a whole generation of the company’s flagship performance models, but only came to US showrooms in the Mark IV Supra Turbo. This engine has found its way into a number of different swaps, including both Lexus IS300/GS300/SC300 models as a replacement for its naturally-aspirated sibling, the 2JZ-GE, as well as other non-Toyotas with engine bays long enough to accommodate the sizeable inline six. 

Could Have Had a V8

Don’t think this is just limited to import brands, either. When Ford ended production of their classic pushrod 5.0 liter V8 engine in the mid-90s and replaced it with the high-tech overhead cam Modular family, it was only a matter of time before those engines started to find their way into Fox-body Mustangs and even classics. One of the disadvantages of overhead cam cylinder heads in a V-configuration engine layout is that compared to pushrod designs of similar displacement, they inevitably end up larger in width and height. Adding cams and timing gear to the top of the cylinders makes them inherently taller than engines that simply have to accommodate rocker arms beneath the valve covers. In a bit of irony, older muscle cars with their large engine bays have more room to accept Modular V8 swaps, making them somewhat easier to work on than modern factory Fords with cramped under-hood layouts. 

While Ford was breaking ties with their previous engine architecture, GM took a less radical path, introducing the first LS-series engines. These successors to the original small-block Chevy V8 and its follow-on “Gen II” LT replacements are in many ways a “what might have been” look at the direction Ford could have taken with their own small-block pushrod architecture. Though the Gen II engines had a lot of problems including a notoriously unreliable optical ignition pickup and were widely panned by gearheads, the Gen III/IV LS family turned out to be a huge success.

Lightweight, powerful, durable, plentiful, and cheap, they quickly replaced the venerable SBC as the engine of choice for GM swaps. Like the aforementioned Honda engines, a huge aftermarket has developed to make putting an LS into an older car easy, right down to complete kits that handle ignition and carburetion should you choose to go old-school and ‘downgrade’ from EFI. Another factor that led to their popularity was that they were manufactured in both iron and aluminum block form, so that those in search of an inexpensive and bomb-proof bottom end could simply grab a low-compression iron block truck motor from the local pick-a-part and feed it a decent amount of boost or nitrous without a lot of drama.

Cross Breeding

While mixing and matching engines and chassis from the same manufacturer often makes things somewhat easier because of shared mechanical and electronic components, taking an engine from one maker and stuffing it into another company’s car has been popular forever as well. As we mentioned before, early hot rodders who started out by putting Ford Flathead V8 engines into Model Ts embraced the original small-block Chevy with great enthusiasm as soon as they started turning up in junkyards. Today, purists will howl in outrage about LS-swapped Fox Mustangs, but a dispassionate look at it shows this is the same kind of thing gearheads have always done. Mustang engine transplants aren’t limited to just Chevy engines either – Most famously, the notable 2006 documentary film The Fast and the Furious: Tokyo Drift included a 1967 Ford Mustang Fastback with a Nissan RB26DETT as a ‘hero car.’

Today, purists will howl in outrage about LS-swapped Fox Mustangs, but a dispassionate look at it shows this is the same kind of thing gearheads have always done…

Like Honda swaps, the popularity of the LS Fox combination has led to an entire range of aftermarket parts to make the process close to turn-key, and all the information necessary to make it happen successfully is easily accessible online and in print. In fact, there has been a strong “LS all the things!” movement in the enthusiast world, with practically every rear wheel drive platform becoming a candidate for a Gen III/IV GM V8 swap. It’s even reached the point where a backlash has occurred against it – many people see the commonality of the LS as a detriment to the originality and creativity of Pro Touring builds, preferring original or at least period-correct engines. Odds are that any SEMA resto-mod build that isn’t intended to specifically highlight another engine will have some flavor of LS power, to the point where it’s become a running joke among writers and photographers.

Regardless of one’s feelings about LS engine transplants, they’re going to be with us for the foreseeable future, and not just in cars. They’ve become the weapon of choice for inboard-powered boats of all kinds, as well as aircraft and even homebuilt helicopters. But eventually something new will come along, and it’s entirely possible that we may one day see all-electric powertrains with ‘universal’ designs developed to simply drop in place of an internal combustion engine and transmission. While one-off attempts at this have come and gone, as the hardware becomes standardized for OEM use (and thus also becomes more affordable) and battery technology advances to increase energy density, peak output, and cruising range, garage mechanics who want something completely different under the hood will embrace these swaps as well. 

About the Author: Paul Huizenga is a California-based freelance contributor who has owned, raced, and written about everything from Subarus to Mustangs to Corvettes over the last two decades. He is currently studying the feasibility of an LS4 engine and transmission swap into a Fox-body to convert it to Chevy power and front-wheel drive, because some men just want to watch the world burn.

Springs vs. Coilovers vs. Bags: What’s the Difference?

Are Springs, Coilovers, or Air Suspension Best for Performance?

It might seem like common sense that having more choices when it comes to just about any decision is a good thing. In many circumstances, that’s true, but when presented with too many options, ‘decision paralysis’ can set in, making it harder instead of easier to choose the right path. Instead of making life easier, it causes anxiety, slows down or even stops decision-making, and can even lead to remorse after the fact as you churn through all the possibilities you didn’t pick. 

When it comes to upgrading a car’s suspension for high performance street or track use, we’ve reached the point where for many popular platforms, there’s no clear winner for every situation out of a wide variety of aftermarket setups. While we can’t guarantee you’ll avoid ‘paralysis by analysis,’ we might be able to help clarify your priorities with the following look at the pros and cons of the three basic categories of mods: Spring and damper replacement, coilover conversion, and air suspension. 

Springs and Shocks/Struts

This category encompasses replacing the factory-spec springs and dampers (whether those are conventional shock absorbers, MacPherson struts, or a combination of the two) with upgraded aftermarket parts.  

Pro:

• Likely to be the least-expensive option, both to buy and to install (if you don’t do it yourself)
• Properly-engineered matching suspension kits take the guesswork out of picking the right spring rates and compression/rebound settings
• Durability is often as good as or better than factory parts
• Some high-end kits offer limited damper adjustment for fine-tuning
• Fewest compromises in ride quality and noise for dual use street/track cars

Con:

• Limited range of spring rates for applications ‘out of the mainstream’
• Systems on the most affordable end of the spectrum usually offer no ride height or damping adjustment

The Bottom Line:

Usually the least-expensive and most-available option, but with significant compromises in adjustability and performance as the tradeoff.

Coilover Conversion

For the purpose of this discussion, we’re going to define coilovers as a complete replacement of the factory spring and damper setup, whether those are individual components or struts, with aftermarket alternatives. This is the most typical choice for serious track applications, but also has a wide fanbase for street/track use as well – partially because of the serious race cred and the ‘hardcore’ aura that goes with the tradeoffs involved. 

Pro: 

• Short of a completely re-engineered suspension right down to the control arms and chassis attachment points, coilovers offer the best possible handling and the widest range of adjustment, as well as more precision and repeatability when changing settings
• Good coverage from multiple manufacturers for the most popular car applications
• Narrower coilover units can offer more clearance for wider wheels and tires without fender modification
• Adjustable ride height without altering spring rates
• Dampers available in configurations from non-adjustable to 4-way (high/low speed compression and rebound)
• Relatively simple and easy to change spring rates with ‘universal’ springs to suit different track conditions

Con: 

• A very, very wide range of quality/price, from pro level down to “I bought this off of Wish – why doesn’t it fit?”
• A whole new form of decision paralysis – lots of adjustment often means more ways to get it wrong
• Systems intended for track use can be noisy and harsh on less-than-perfect pavement
• Expect to either replace or rebuild the dampers on a regular basis, as they are usually designed with longevity as a lower priority
• Less-common performance cars may need to have coilover sets pieced together from components if ‘all in one box’ kits aren’t available

The Bottom Line:

Not the best choice for comfort or street driving, but the de-facto standard for full-race use. Beware of pitfalls in quality at the low end of the scale, and excessive complexity at the high end.

Air Suspension

Commonly referred to as “bags,” today’s performance-oriented air suspension systems are a far cry from the lashed-together rigs that pioneered the technology. Once strictly an option for “stance” and car shows instead of performance, it’s now a solid contender for track-oriented builds.

Pro:

• Adjustable ride height is the main attraction here – modern air springs offer a wide range of spring heights selectable simply by adding or reducing pressure, and clever design of the air bags themselves achieves this without significant changes in spring rate
• Compatible with multi-adjustable race-spec dampers for suspension tuning
• Systems with quality air springs rival conventional factory steel springs for durability
• A great choice for cars that will see use on both the race course and the street, making low ride height that would be a disaster with a ‘static’ coilover suspension achievable in a car you can still drive to and from the track
• Complete, ready-to-install kits are available for more applications every day

Con: 

• Trends towards the expensive end of the scale compared to anything but full-race coilover systems
• Additional hardware like compressors, tanks, solenoids, and pressure gauges required for adjustment on-the-fly, which adds expense and weight
• Modern air springs only allow changes in ride height while spring rate remains the same, requiring complete replacement of a relatively expensive component to alter it
• Like coilovers, less-popular applications may require ‘a la carte’ component selection instead of an off-the-shelf solution

The Bottom Line:
The king of adjustability, at the expense of additional weight and cost. Limited (but growing) off-the-shelf choices.

Wrapping it Up

There’s no one-size-fits all solution to picking the right path for the suspension on your project car or daily driver, and the wide variety of choices (made worse by conflicting advice from all directions) doesn’t help. Hopefully we’ve made it a little bit easier for you to organize your priorities, from the cost involved to the complexity of installation and tuning to your personal intended use (which often turns out to be somewhat different from where you actually end up in practice). Relax, take a deep breath, and consider the options we have set before you as a starting point in your search for the perfect suspension.

Are 35 Inch Tires Right for Your Rig?

The number one question people ask about is what size tire will fit my vehicle. Nothing gives your off road vehicle a more aggressive look than larger tires, and custom wheels. Fortunately, larger tires will give you just as much of a performance gain as they do a visual enhancement. One of the most popular tire sizes is a 35 inch tall tire. Depending on your vehicle, 35 inch tires could be a simple bolt on process, or entail several modifications in order to make them fit. If you have an AWD, car based overlander, or small SUV, you might want to try something smaller. On the other hand, a full size truck can allow enough clearance to bolt on 35’s with no issues. 

Automotive designers tend to make the wheel openings tall, but narrow. It probably has to do with aerodynamics. The wind turbulence created by wheel openings affects the coefficient of drag considerably which also reduces fuel mileage. Despite their good intentions, the lack of clearance is a real issue. Modern trucks have plastic fender flares, and side body cladding that can also hamper your efforts to fit larger than standard tires. In the past you could simply get out a saw, and cut the sheet metal away. Most people with new vehicles frown upon this as it is irreversible. Many don’t want to cut into such a large investment; that’s why lift kits are used. Not only do lift kits give additional ground clearance, but they also provide more room for larger tires.  

So why go to all that trouble you may ask? The answer is because your tires are the only thing between you and the dirt. Would you rather hike a trail in a pair of ice skates, or hiking boots? Some of us wouldn’t want to be on ice with ice skates let alone on a trail, but that’s another topic. Once you have increased the width of your tires, the only other way to increase the size of the contact patch is with a larger diameter. The contact patch is the surface area of the tire that directly makes contact with the ground. As the tire gets wider, the contact patch increases in width. As the tire diameter increases, the contact patch also grows in length. Increasing the length of your contact patch can give you much more contact patch on the ground. The size of the contact patch is critical because it provides the grip needed to stop, go, and turn. Increasing the contact patch is the easiest way to get better control. 

So why stop at 35 inches, why not go even bigger? That’s a great question, and the reason is simple. Once your tires reach a certain size, they start to affect other parts of your vehicle. They will put a strain on driveline components, and your gear ratio might not be suitable to allow the engine to operate in the correct RPM range that it needs. The bigger tires may be too much for your steering components as the contact patch creates so much grip. You also need to consider your brakes. You can see that once you start making changes to your vehicle, it creates a huge snowball rolling downhill. You will end up spending thousands of dollars, and entirely re-engineering your vehicle. That’s why tires in the range of 32 to 35 inches are popular upgrades. They can be made to work without too much disturbance of your factory systems. Some people have trail only vehicles, but most of us also want to drive on the street, or commute to work.

A 35 inch tall tire is still a big tire. It will affect your final drive ratio, and your braking, but many people will gladly accept that for the increase in traction. There is a camp that typically drives in muddy conditions who like tall narrow tires. They contend that the skinny tire cuts through the mud, and gets down to firm earth where there is traction. This only works if there is a bottom to the mud. If the mud is deeper than the distance between the surface of the mud, and your truck’s frame or the body, then you are likely to get stuck. A wider tire will provide flotation. Instead of cutting into the mud, it will resist sinking in; allowing the vehicle to remain on top. As many people know, and all will find out, mud doesn’t care either way. You can get stuck using a skinny, or a wide tire. The skinny tire concept is somewhat specialized. It doesn’t work on wet roads, or sand. That’s why most people prefer a wider tire. 

Personally, I like the way my vehicles handle with a large, wide tire. It feels much more stable to me, and it helps to build confidence when in certain off camber, or loose conditions. A larger tire also comes in handy when you are traversing ruts. Most of the time, it’s much better to roll over the ruts, than to fall into them. If you are driving the same direction as the ruts, you may only have an inch of tire still riding on the top edge, and that’s all it takes to stay on top. The same goes for washouts, or obstacles. When you come up to an obstacle that needs to be scaled, a taller tire will roll over it much easier than a shorter tire. The shorter tire will need to climb up the obstacle while the taller tire will have more of a tendency to roll over it. 

So you see, there is a reason why 35 inch tall tires are so popular. For most vehicles, they give you as much performance as possible without negatively impacting your vehicle. Like all modifications, you need to weigh the positives with the negatives. Most people will agree after weighing the options that installing 35 inch tall tires on your rig will give it the performance you want in the dirt, and set you apart from all the stock trucks out there.            

What Is a Supercharger?

Which Is the Right One for Your Car or Truck?

Most custom car and truck enthusiasts pay lots of attention to their engines. While keeping them in tip-top running condition is a given, increasing performance is always a more interesting topic of conversation. Now, there are plenty of methods to bumping up horsepower and torque output, from simple bolt-ons to digital reconfigurations (depending on the vehicle), but one of the most popular pieces of equipment to add more power in a hurry is a supercharger. 

While the blanket “supercharged” term does get the point across—that there is major performance enhancement made to an engine, there is more to understanding exactly how that enhancement is made. Some might not care all too much to know the details, but to inquisitive minds, knowing what type of supercharger that is attached to an engine tells a lot about where the extra power is coming from and how. 

What Is a Supercharger? 

Those who are even somewhat familiar with how engines work know that the more oxygen that is introduced to an engine, the better. Building on that basic theory, a supercharger basically creates and injects more (much more) oxygen into an engine, which in turn, increases fuel burning efficiency. This directly increases the amount of power that engine can put out. Now, there are different types of superchargers that vary in the way of accomplishing that exact mission, which we will expand upon soon enough, but for the purposes of building a good foundation of information, let’s first understand this first piece of the equation. 

What A Supercharger Is NOT!

The terms “supercharged” and “turbocharged” may sound like they could be interchangeable. Granted, both are in essence very similar, as they are both air compressors that “charge” an engine with a much-higher-than-normal flow of oxygen into the combustion chamber, but it’s the way they get that job done that presents the difference between them. 

Any type of supercharger is a “parasite” in the sense that is it powered by the very source (the engine) that it is designed to enhance. It’s belt-driven by the crankshaft (or an electric motor in some cases), and while a supercharger does require energy to function, the amount of energy it allows an engine to make far exceeds its cost of operation. A turbocharger, on the other hand, utilizes the velocity of expelled exhaust gasses to create energy that, in turn, directs more air into the engine. Props to the turbo for turning wasted energy into a renewable source of power though, right? 

Three Major Types of Superchargers

While there are other types of superchargers out there, there are three notable variations that you may already be familiar with. While you may not have known the exact difference(s) between these styles, they do provide their each set of pros and cons depending on their application. As previously mentioned, each of these superchargers is dependent on power from the engine to operate, but the fashion in which each operates is a bit different. But of course, each is designed to provide the same end result. 

Roots “Blower” Supercharger

You’ve heard of a blower, right? Well, in case you didn’t know exactly what somebody was referring to when talking about their latest engine tweak, a roots type supercharger is what they mentioned. The path of air in which the blower starts with comes directly from the air intake, through the throttle body, into the supercharger, where two oppositely spinning, lobed rotors are doing their thing. These rotors direct the high capacity oxygen through an intercooler (because this process does produce high levels of heat) and into the engine where the rate of combustion is increased, which in turn makes all the extra power. The roots supercharger is ultra reliable, probably the most inexpensive across the board, and offers good low RPM boost, making it highly appealing. 

Twin Screw Supercharger

The twin screw design is similar to the roots supercharger as far as set up, placement on the engine and overall appearance is concerned. It is inside the supercharger itself where the mechanics make all the difference. Instead of spinning away from each other, as in the roots style, the two rotors (screws) spin towards each other, and because of the design of these rotors, the air is compressed inside this supercharger, and not in the engine itself as with the roots style units. This directly leads to higher thermal efficiency. 

BOTH the roots and twin screw superchargers are positive displacement types, which simply means that torque levels are increased across the RPM board. So, whether you’re cruising around town or have the pedal mashed to the metal, you’ll experience increased performance gains throughout. 

Centrifugal Supercharger 

The design of the centrifugal supercharger is a lot like a turbocharger, as both rely on an impeller to suck in air at an increased rate, then distribute that air through the rest of the engine system. Instead of being powered off exhaust gases like the turbocharger, however, the centrifugal supercharger is still belt-driven by the engine, unless it is an electric style that would be equipped with its own alternator, battery and motor.  

The centrifugal design also differs from the roots and twin screw superchargers being that it is not a positive displacement unit. Since the impeller on a mechanical (non-electric) centrifugal charger only spins as fast as the engine’s RPM output at any given time, there really is only a major increase of torque at the top end RPM range. The electric version offers much better performance at all RPM ranges but there is a considerable amount of extra equipment that also goes along with the installation. 

Also consider the fact that the actual size of centrifugal type superchargers are much more compact than the two others, and don’t have to be mounted vertically on top of the engine like they do either. It can be placed “before” the throttle body, and therefore is much more flexible as far as placement on the engine. 

Superchargers make a big difference under the hood, and luckily there are multiple types to ensure that there is an absolute right one to best meet your vehicle’s individual needs. And if the right supercharger for the job turns out to be a turbocharger, well then, hey go ahead and run with it. 

A Streamlined Guide to Aero

What Do All Those Wings and Fins Do, Really?

Getting into the subject of aerodynamics as they relate to cars is asking for trouble. Whether you’re talking about imports with big goofy wings and dive planes that look like anime road catfish, or even just owners of a certain domestic brand who steadfastly refuse to remove the banana-yellow shipping guards on their cars’ factory splitters, it’s a topic that draws a lot of derision. Sometimes that’s warranted, but there is a place for aero mods in the tuner’s toolbox. Understanding the goals of functional aero is the first step in moving from the realm of questionable styling choices into something worth doing for the sake of improved performance. We’re going to jump in with both feet and banish the poser-tech to the Land of Wind and Ghosts, so hang on…

No Free Lunch

Aerodynamic modifications to a car serve one or both of two main functions; reducing drag and reducing lift. Most changes affect both drag and lift, and while downforce can be important, achieving meaningful results in that area without a huge drag penalty can require some finesse. Drag is especially important because it increases with the cube of velocity – drag-inducing elements of a vehicle’s design that aren’t worth worrying about at low speed become big problems on the highway or racetrack. Like almost any part of car design, the ability to maximize the desired effects while minimizing the drawbacks is what separates winners and losers.

An excellent example of this that’s become ubiquitous over the last two decades in OEM car designs is limiting the volume of air that passes underneath a car. In older designs, this was a source of both lift and drag, and as a result, modern vehicles have become lower and they’ve added aerodynamic features to the nose of the car to redirect flow. These changes cost virtually nothing for manufacturers to implement but provide real benefits.

One area of special attention that was often poorly-understood or simply ignored in the past was air passing through the front grille, into the engine bay, and out through the open underside. Smaller air inlets better-sized to the radiator core and ‘bottom breather’ noses that actually relieve pressure at the lowest point under the bumper, plus aerodynamic trays covering the underside of the engine compartment are all examples of the way modern designs improve aero in this region.

We have to admit that we’ve been among those who have either intentionally removed an engine bay undertray to make maintenance less of a pain, or simply lost one due to ill-advised encounters with curb stops or speed bumps, but not having them in place as intended is a significant source of both drag and lift. There’s little point in trying to improve aerodynamics at the nose of the vehicle with added parts if the primary flow-control features of the factory design are missing. 

Presuming that you’re starting from an intact, OEM aero standpoint, is it possible to modify things yourself and achieve meaningful, non-cosmetic results? The answer is a qualified yes – like every other aspect of automotive engineering, factory designs are always a compromise between competing goals, and the compromises you might choose as an enthusiast aren’t always the same as the ones that are aimed at satisfying the greatest number of ‘normie’ potential customers. In the case of aero, low drag, stable handling at freeway speed, and low noise top the factory wish list. 

As an enthusiast, you may be willing to trade away some extra drag (and lose a bit of fuel economy at cruise) in exchange for added downforce to improve traction. Increased wind noise may also not be a concern for you, and you might be willing to accept the negative consequences of a lower ride height, like increased susceptibility to damage from potholes and curbs. These are just a couple of considerations when planning out aero changes to your vehicle. 

With all this in mind, let’s start from the front and work our way back, describing different aero components and how they function (or at least are supposed to function).

Nose Dive

It used to be that air dams with splitters (a horizontal plate attached at the bottom of the air dam) were only seen on race cars, but they’re appearing with greater and greater frequency on factory cars as well – often with the aforementioned plastic protective bananas still attached, because reasons. The purpose of a splitter is to cleanly divide flow between the air moving around and through the nose of the car and the air traveling underneath the body, as well as limiting how much air goes low instead of high. To be truly effective, splitters need to be quite close to the ground, and even though factory-designed ones are usually higher than ideal, they still provide an endless source of horrible scraping noises over curbs, driveway entrances, and other obstacles if the driver isn’t careful. 

A properly-designed splitter and air dam combo will reduce both drag and front end lift by reducing turbulent flow to the underbody, and will also help the engine bay tray (if present) to do its job. A secondary purpose is to help guide flow around the front wheel openings, which are a major source of drag. 

Dive planes, canards, fins, or whatever you want to call other small aero devices placed on the quarter panel in front of the wheel arches also serve this purpose, as do longitudinal fences at the gap between the fender and the hood. Properly engineered canards can also help promote the flow of air from brake cooling ducts that source air from the high pressure area in the bumper by creating a local region of lower pressure to draw air away from the rotors and wheels after it has done its job. 

Care has to be taken with hood fences, though – viewed in profile, a car is shaped somewhat like an airplane wing, and just like a wing, air that is accelerated over the upper side creates an area of reduced pressure, generating lift. Ideally, fences will keep high pressure air from spilling over the fenders (thus increasing front downforce) without forcing it to follow the curve of the windshield over, rather than around, the passenger cabin. Fences, as well as canards/dive planes to a lesser extent, can also greatly increase turbulence around external mirrors – while this isn’t a huge source of extra drag, it can create a lot of interior noise ranging from a very-low-frequency ‘brown note’ rumble to intolerable high-pitched whistling. 

Side View

Extended lower sills along the sides of the body are another example of managing airflow beneath the vehicle. Like splitters, to be completely effective they need to be impractically (at least for on-road use) close to the ground, but they aren’t totally useless even when compromised for the sake of clearance. 

An interesting side note here is that a number of competition vehicles, ranging from the 1970 Chaparral 2J Can Am car to modern Formula SAE karts have been built with ‘powered downforce’ using a fan to pull air from underneath the car. Working like a reverse hovercraft of sorts, the front, sides, and rear of the underbody were sealed to the road surface via flexible skirts with polycarbonate sliders at the bottom to reduce air leakage, and a slight vacuum created by the fan across the entire underside of the car delivered enormous downforce at zero MPH with no aerodynamic drag. It was said that the 2J could develop enough suction to allow it to stick to the roof of a tunnel at a standstill, and the pair of 17 inch fans, driven by a separate snowmobile engine, could drive the car forward at 40 MPH just by their thrust alone.

Of course, in Can Am competition the technology was immediately outlawed, as these things tend to be, but in racing situations where it isn’t outright banned by the rulebook, this unique form of “aero” is still an extremely effective one. In the real world with roads that aren’t billiard-table smooth, the skirts take a beating, and getting rocks and dirt actively sucked up through powered fans does not make the people driving behind you very happy. Nonetheless, a good front splitter and side skirts, combined with a rear end shaped to create a low pressure area can still take advantage of this same effect, though only in motion and with much less total downforce. 

On the roof of the car, vortex generators can be fitted along the back edge just ahead of the rear window. These are small triangular features that are actually designed to create turbulence, but in a very controlled way. By inducing a narrow band of swirling flow, they act in the same way as a solid fence and can help keep flow attached to a surface, with a small drag penalty. Originally vortex generators (as well as fences) were found on aircraft wings as a way to stop span-wise (side to side) airflow and improve stall performance. In the automotive world, you’ve undoubtedly seen these on factory Mitsubishi EVO sedans, and their budget cousins can easily be found in the stick-on plastic whatsis aisle at your local auto parts store, alongside portholes, fake vents, and chrome Punisher symbols. Usually, these cheap little pyramids are poser tech, but they can actually be effective when used in the right spots. Unfortunately, without sticking tufts of yarn all over the outside of the car to see how air is moving locally across the roof and backlight, the ‘right spots’ are impossible to determine beyond an educated guess. 

Winging It (Spoiler Alert)

Finally, we get to what you’ve all been waiting for, the defining piece of aero hardware – the wing or spoiler. First, though, please understand that the terms aren’t interchangeable, and although both reduce lift/increase downforce on the rear end of the vehicle, they do it in different ways. Let’s start with the simpler of the two, the spoiler. 

The name for this aerodynamic device comes directly from its function; ‘spoiling’ the lift of a wing-shaped surface. Earlier, we described how the body of the entire car in side-view resembles an aircraft wing with a curved upper surface, and just like an aircraft wing, since air has to travel farther and faster across the top than the bottom, it will generate lift. A spoiler on the back of the car works exactly as it would on a wing, disrupting that flow of air to kill some of the lift being produced. 

Just as importantly, a spoiler can actually reduce total aerodynamic drag despite being an impediment to the smooth flow of air. Back at the dawn of ‘streamlining’ (as aerodynamics were first called 100 or so years ago) inventors looked at the teardrop shape of a falling droplet of water and concluded that nature was providing them with a blueprint for the perfect low-drag shape. As a result, a lot of the first efforts at streamlining included long, pointed tails to allow the airflow to smoothly rejoin behind the vehicle without producing an area of low pressure.  

As zippy as these designs looked, they were somewhat impractical for road vehicles, and designers searched for other solutions. The most successful was developed by a German fellow by the name of Wunibald Kamm in the late ‘30s when he discovered that an abruptly cut off vertical shape at the back of the car was nearly as effective in reducing drag as a pointed tail. By inducing some of the boundary layer air close to the surface of the body to tumble into that space behind the car, it created an area of turbulence that didn’t mix with the other air flowing around the car and worked like an invisible (and weightless) pointed tail.

Since that time, the “Kammback” has been widely adopted, and can be seen in cars ranging from the original Honda CRX to many modern hybrids. For best results, the vertical surface should be placed at a point where the body’s cross section has sloped back down to about 50% of its maximum, but this limits the workable roofline and tail shapes quite a bit. Add a spoiler to the trunk lid or the back edge of the roof on a hatchback, though, and you get a similar drag reducing effect as a full Kamm rearend. 

Wings, particularly those that are intended to do something more than just look cool, are somewhat more complex. Ideally, a wing will be placed far enough away from the body of the car to be in “clean” air instead of sluggish and turbulent boundary layer flow. Interestingly, the 1969 Dodge Charger Daytona and 1970 Plymouth Superbird, with their fender-mounted ‘basket handle’ rear wings that were higher than the roofline had ideal placement for them, but it wasn’t for aero reasons – they had to be that high so that the trunk lid could still open underneath them!

A few years earlier, the Chaparral 2E Can Am design had debuted a tall strut-mounted rear wing that had what would be now considered “active aero” – A pedal on the floor would flatten out the angle of the wing and simultaneously close a shutter on the air dam that normally allowed air out through a vent in the front bodywork when depressed, letting the driver reduce drag when downforce wasn’t needed along high speed straights. The struts for the wing were also directly connected to the suspension, so force was applied straight to the rear tires instead of through the springs. While it worked very well, it proved to be fragile and after a few failures in the cars adopting these kinds of movable wings, they were outlawed (leading to the aforementioned Chaparral 2J ‘sucker car’).

Today, it is very common to see high-end (and even some not so high-end) sports cars with rear wings that automatically deploy and adjust their angle based on road speed and cornering forces. For aftermarket race-style wings, the angle of the airfoil (or in many cases, multiple airfoils) can be changed in the garage by altering the mounting points in order to customize the balance between drag and downforce for a particular race venue. Spill plates on the ends of the wing serve the same purpose as the winglets commonly found on commercial jets, reducing drag caused by vortexes shed by the ends of the wings. 

It’s also worth noting that a wing can help high-speed stability side-to-side by moving the car’s center of pressure rearward. The center of pressure is the imaginary point where all the aerodynamic forces are balanced, and the farther behind the car’s center of gravity it is, the more the car will want to travel in a straight line. Any kid who’s built a model rocket and decided to put all sorts of fins on the front will tell you that having the center of pressure at or ahead of the center of mass gets you something that flies like a pinwheel instead of an arrow, and the same applies to car aerodynamics. We should also point out that the ever-popular ‘wing on the back of a FWD car’ isn’t necessarily just poser-tech. At high speed the car doesn’t care that much about which wheels are doing the motivating, and since FWD cars tend to have a forward weight bias in the first place, a properly-designed rear wing can greatly increase stability and cornering balance.

Finally, we get to the last details as we reach the very tail end of the car. Wings and spoilers often have small features on their rear lips to enhance their effectiveness, which can be either fixed or adjustable. A small tab, usually a half-inch high or less and mounted at the very trailing edge of a wing or spoiler at a right angle to the surface is usually referred to as a “Gurney flap.” It gets its name from the legendary racer and team owner Dan Gurney who came up with the idea as a quick handling fix for his driver Bobby Unser’s car. To hide the true purpose of the modification, he initially floated the story that it was just a way to protect crewmembers from the sharp trailing edge of the wing while working on or pushing the car, but soon enough everybody figured it out and it became commonplace in race car aerodynamics.

A taller, usually adjustable trailing edge lip is typically called a ‘wickerbill,’ and explanations for the name are easy to come by but none are definitive. These fall into the category of aero devices that can be tuned in the garage or pit to suit the race course by sliding them up or down in their mounting slots. 

So there you have it – the incomplete guide to understanding car aerodynamics. We hope that we’ve fired your imagination and that you’ll follow up on the subject with further reading, since it’s a topic of pretty high importance for both factory and modified vehicles. Plus, aero stuff looks cool when it’s done right, but you already knew that…

Long Wheelbase and Short, The Pros, and Cons.

I’ll cut to the chase right now, there is no “winner” when it comes to the debate over short wheelbase or long; they are two separate things like apples and oranges. Instead we can talk about their strengths and weaknesses. Your local trail might have rocks, or mud, or sand on the same trail. Unless your area offers only one single type of terrain, you will have to make a choice which is better for your particular likes, and dislikes. We can look at data, but in the end, it will come down to your own opinion which works best for you. 

“The FORD’s wheelbase is, wait for it, 168.4 inches. That’s over twice as long as the Jeep.”

Since we are in the realm of opinion, I will offer mine. I come by my opinion after owning both long and short wheelbase 4×4’s, and wheeling them in varied terrain. The first 4 wheel drive I ever owned was a 1984 Jeep CJ7 which I bought new off the lot. It had the 258 inline 6, and a manual 4 speed transmission. I was living, and wheeling in the mountains, so for self-preservation I kept it low to the ground. I had an add a leaf in each spring, and extended shackles. The minimum lift was to clear the 36 inch tall Goodyear Wrangler R/T tires. Out of my group, I was the only truck not to end up on its lid, so I was doing something right. The Jeeps wheelbase was 83.5 inches.

My long wheelbase truck is the one I currently own. It’s a 1992 FORD F350 4×4 crew cab. Yes, it’s a beast. I’ve installed a shackle reversal kit in the front to improve the ride quality which lifts the truck about 5 inches. The front kit also uses longer superduty length leaf springs, and custom Atlas springs in the rear level the truck and further improve the handling. It rides on 37 inch tall tires. With the longer wheelbase, additional height is not as much as a concern. I have a classic Warn winch bumper on front with an original Warn M10000 winch that has only been used to winch a fallen tree on my neighbor’s property, and other trucks that have gotten stuck. I have never been stuck in this truck so far, (I’ve owned it for 6 years). The FORD’s wheelbase is, wait for it, 168.4 inches. That’s over twice as long as the Jeep.

“There are places where the long wheelbase just will not fit. In more open terrain, the long wheelbase can hold its own.”

Now that I have quantified my bonafides, let’s get into the meat of the subject. One thing I really liked about the Jeep had nothing to do with performance, but it rates mentioning. Between the 36 inch tires, and 3” diameter side bars, those jerks that open their door into yours in the parking lot were entirely inconsequential. They hit either rubber, or steel. Door dings or paint chipping was not even possible. The big FORD has a mile of sheet metal that gets dinged all the time. The truck is big, and parking stalls get smaller all the time.

When I owned the Jeep I was either hitting local trails in the Santa Cruz Mountains, or spending time out at the Hollister Hills OHV Park. Hollister had an obstacle course that included a tire pit. The tire pit was instant doom for the short wheelbase. The front tires would kick those loose tires right up into the back axle; wedging them between the tires, and the frame. Most of you won’t find a tire pit out on the trail, but the same goes for branches, or any other unsecure flotsam you might find. The short wheelbase means both front and rear axles will be in the same situation.

If it’s rocky, both will be in the rocks. The same is true for mud or loose sand. With the longer wheelbase, the front and rear axles can be in different time zones. While the front tires are clawing through a mud hole, the rear tires can be getting excellent traction in drier or less slippery conditions. For pure traction, I give the advantage to the longer wheelbase. One thing that beats the long wheelbase is that the shorter wheelbase is so much more maneuverable. You can fit it in tighter spots which might allow you to avoid the hazard all together. When it comes to hill climbing, the same maneuverability of the short wheelbase can cause problems. Backing down a hill is much more challenging because slight inputs to the steering wheel will cause the rear end to change direction abruptly. On the other hand, during a failed attempt you might be able to whip the Jeep around, and drive straight down the hill. That would just not be possible in the big FORD. Some say that the long wheelbase has an advantage during side-hilling, but I will give put that in the toss up category. The long wheelbase has the greater risk of getting high centered. I have found that the traction advantage, and the fact that you can usually rock the truck back and forth until you get traction makes it easier to get back on your wheels with the long wheelbase. If you do get high centered with a short wheelbase, you are generally screwed. It’s a good chance that both axles will be off the ground. 

When it comes to tight trails, the short wheelbase wins hands down. There are places where the long wheelbase just will not fit. In more open terrain, the long wheelbase can hold its own. Based on pure performance it’s a matter of preference, but you also have to consider utility. One of the biggest drawbacks of the short wheelbase rig is limited cargo room. It’s easy to take some of the capabilities away if you add a roof top rack, or tons of weight hanging off the back because there is no room inside the vehicle. You have much more room to place your gear down low, and between the axles in the bigger truck.

If you are towing, it’s no contest. My FORD will tow anything, and you won’t be able to tell it’s back there. The same goes for ride quality. The short wheelbase and short body means that the leaf springs or suspension links will also be short. The result is less wheel travel, and a choppy ride. The big truck rides surprisingly well after the leaf spring upgrades. The limiting factor is the weight capacity. A certain amount of spring rate is necessary if you want to tow, or carry a slide in camper. You see, the two are really not the same. There is a solution available that will give you the best of both. Tow your Jeep behind your big truck on a trailer. 

Brake Kit Upgrades for Racing Applications

Really great brakes are like an upgrade to your confidence on the track – more deceleration on tap means lower lap times thanks to being able to go deeper into corners, and less fade gives you the reassurance to do it corner after corner and lap after lap. But it’s not as simple as just slapping on a brake kit with the biggest rotors and largest calipers that will clear your wheels, and it’s even possible to have “too much” brake, making the car a chore to drive and slowing you down even when you’re not using them.

Today, we’re going to look at some useful information when it comes to putting together a brake kit for competition, and how to get the most out of the hardware you’ve selected. We’ll concentrate on circuit racing, including autocross, time attack, and open track days; while brakes for drag racing are also a complicated subject, they’re a different kind of animal thanks to the special demands of straight-line competition, and are beyond the scope of what we’re talking about here.

When it comes to how effective brakes will be, it all comes down to the interface between the rotor and the pad – everything else simply serves to support this relationship. At a microscopic level, a properly-bedded-in cast-iron rotor will actually have some pad material embedded in its surface, and pad compounds and rotor metallurgy both take this into account. Before using any new brake kit in practice or competition, you must make sure that the pads and rotors have gotten to know each other properly via the manufacturer’s recommended break-in process. This goes for spare pads as well; if you are competing in a form of racing where you’ll go through more than a single set of pads in a weekend (or a single race, for those running endurance events), you’ll need to make sure your spares are already broken in and ready for use.

…it’s even possible to have “too much” brake, making the car a chore to drive…

Speaking of pads, this is an area where a racer has a lot of opportunity to “tune” brake performance to their liking. One popular manufacturer of racing brake pads offers no less than  nine different compounds just for motorsports applications (and a similar number for high performance street use), with a range of different characteristics and performance trade-offs.

The first aspect of a pad compound to consider is torque – how much grip the pad can apply to the rotor, using the available pressure from the caliper. While this might sound like the start and end of the story, consider the fact that a broomstick jammed into the spokes of your bicycle will deliver more brake torque than you can effectively use.

Peak torque is an important factor for cars with a lot of grip from big, sticky race compound tires, a lot of downforce, or both. But in order to be useful, that torque has to be available in a controlled way, and pad compounds can be formulated to adjust how it is delivered. Cars with limited traction under braking can benefit from compounds designed with a linear torque delivery, to allow the driver to modulate braking short of lock-up (or ABS activation, in situations where that’s a factor.)

While this might sound like the start and end of the story, consider the fact that a broomstick jammed into the spokes of your bicycle will deliver more brake torque than you can effectively use.

You’ll also hear the term “bite” to describe initial braking force – cars with a lot of downforce and/or tire grip can take advantage of pads with a lot of it because the first moments of braking deliver the most deceleration, but quite often, drivers will describe brakes with high initial bite as “grabby” and there can be a steep learning curve before you become comfortable with the non-linear torque characteristics. “Release” is the flip side of bite, describing the brake feel as pressure comes off the pedal, and pads with good release characteristics are easier to modulate at the very edge of tire traction.

Heat tolerance and rotor wear are the two other major dimensions of compound selection. For situations like autocross or (to some extent) time attack where your brakes are going to start off cold and then be subjected to a large heat load, you’ll want a pad composition that is engineered to deliver consistent torque across a wide heat range, possibly at the expense of developing some fade if the heat input exceeds the ability of the system to shed it over a longer time period. For multi-lap track day use or wheel to wheel competition where it will be possible to get the pads and rotors up to a ‘working temperature’ and keep them there, a composition optimized to deal with heat that trades off poor cold torque is going to make more sense.

For high-end racing applications, carbon brake rotors and matching pads offer the widest range of heat tolerance without fading. In the past, these were competition-only parts due to their poor performance when cold, their lack of durability, and their sensitivity to pad/rotor contamination, but recent years have seen them make their way into many OEM applications in sports cars as well. These brake setups are far more reliable and capable than the track-only carbon brakes of the past, but they carry very steep initial costs and replacement of the consumable components is expensive as well. It’s not unheard of for some non-professional racers to ‘downgrade’ to metallic brake rotors and conventional pads to keep costs for a season of racing in check.

…a vented rotor will also be more rigid, ounce for ounce, than a solid one.

Since we mentioned consumable components, it’s definitely worth talking about rotors at this point. Once you begin to put laps on your car, you will quickly discover that it’s not just the friction material in the pads that wears out – brake rotors have a finite lifespan as well, and should be considered a component that requires scheduled replacement. There are numerous styles of rotors available, but the vast majority you’ll see that are suitable for competition are “vented” designs. These rotors have two friction faces separated by cast-in vanes that allow air to circulate from the hub center to the outside of the rotor, helped by centrifugal force.

There’s some debate about just how effective this circulation actually is – the amount of air being moved is small, and it’s likely that the biggest advantages of a vented rotor design over a solid disk are increased mass to act as a heat sink, and improved dimensional stability. In the same way that a box girder resists being deformed better than a flat plate made from the same amount of material, a vented rotor will also be more rigid, ounce for ounce, than a solid one.

You’ll also see a lot of debate about drilled and slotted rotors. In theory, both allow trapped gasses and debris to escape from the interface between the pad and the rotor, but in recent years drilled designs have fallen out of favor to some extent as many manufacturers and users believe that holes provide starting points for cracks in the rotor surface without offering a significant difference in performance over slots that don’t completely pierce the rotor faces. This impression wasn’t helped by the flood of cheap “drilled” rotors that came on the market that were simply some small ‘manufacturer’ taking an OEM part and throwing it on a mill to put some holes in it without any consideration for the overall strength of the rotor. You will also see debate about the advantages of a two-piece rotor assembly over one that is cast as a single component. Primarily, these claimed benefits fall into two categories; one, a rotor assembly with a separate disc is less expensive to maintain because the friction surface can be replaced independent of the mounting “hat,” and two, if the rotor is designed to “float” on the hat (which is quite typical of motorcycle applications, but less so in four-wheel vehicle designs) distortion of the rotor from expansion and contraction is reduced.

Finally, there is the question of caliper selection. Once again, there is a huge range of possibilities in terms of piston count and other features, but for most sportsman-level racers in economical classes, the biggest bang for the buck will come from an upgrade from factory “floating” calipers that have a single piston and rely on the entire housing shifting on its mounts to apply even pressure to the rotor to a design with opposed pistons. Most cars with sporting aspirations will come from the factory with opposed-piston calipers, which can benefit from an upgrade to designs that offer staggered piston size for more consistent pad wear, additional pistons to spread clamping force over a larger swept area, or calipers and matching mounting brackets that allow an upgrade in rotor size to take full advantage of the room available within larger-diameter wheels.

We’ve obviously just scratched the surface of this topic, but hopefully we’ve provided a jumping-off point for further research into competition brake upgrades. Remember – a car that won’t start is just an inconvenience, but a car that won’t stop will ruin your whole day.

The 2021 Ford Bronco: What to Expect

The Blue Oval Boys Take On the Jeep Wrangler on Its Home Turf.
Do They Have the Right Formula to Unseat the King of Hardcore Off-Roading?

For the last 75 years, Jeep has been the brand to beat when it comes to street cred where the streets end. From the original civilian CJ-2A to today’s JL Wrangler, they’ve set the standard for no-compromises off-road performance straight off the showroom floor. Throughout that long, successful run they’ve faced many challengers; the Toyota Land Cruiser, the Chevy Blazer, the International Scout, and of course the Ford Bronco.

Though they all found their own fans, over the past few decades all those nameplates have fallen to the wayside, leaving only Jeep still selling vehicles that are so strongly biased in favor of all terrain performance over creature comforts and day to day practicality.

Now, Ford is poised to take a run at the Wrangler with the 2021 Bronco, which will be revealed in full to the world on Monday, June 13, 2020. This long-rumored return of a classic off-roader shows every sign of being specifically targeted at the same market segment as the JL, but can it really go toe-to-toe with Jeep’s flagship? Here’s what we know so far…

There Will Be Three Different Broncos

This is a mortal lock, based on what Ford has already shown us. The lineup will include a 2-door, a 4-door, and the Bronco Sport. But honestly, you can just ignore the Sport – it isn’t going to share anything but a nameplate with the “real” Bronco, and is going to be positioned as a competitor to softroaders like the Jeep Renegade, not the Wrangler. A pickup version to compete with the Jeep Gladiator is possible as a follow-on in subsequent model years, depending on how sales of that model (as well as the 2- and 4-door Bronco) pan out.

The Doors Will Be Removable (Without Tools)

US Patent 10,550,615 B2 granted to Ford in February describes a “door hinge assembly incorporating a latch to facilitate selective door removal.” Unlike the Wrangler, it seems that the Bronco’s doors will be easy to remove and replace without needing any tools. Ford has also filed multiple patents for things like doors with separate skins that leave a side-impact protection structure in place when removed, an airbag compatible with a detachable door, and even retractable safety rails between the front and rear pillars that are either constantly in place when the doors are off, or activate automatically in the event of a crash. Ford would undoubtedly prefer for you to keep the doors on your new Bronco while driving on the road in the name of greater occupant safety (and will also certainly put a lot of warnings about it in the manual, where nobody will read them), but based on the fact that the hinge latch patent has not just been applied for but granted, that seems very likely to be incorporated at launch.

The Bronco Will Have Body-On-Frame Construction and a Solid Rear Axle With IFS

The rumor is that the Bronco will be built on the same platform as the new mid-size Ranger pickup in the same facility, and that implies a separate traditional ladder frame instead of unibody construction. That’s good news for the aftermarket, as it will allow body lifts to easily accommodate larger-diameter tire fitments without re-engineering suspension components, plus many people will prefer that design’s inherent ruggedness for serious off-roading. The Bronco will also almost certainly have a coil-sprung solid rear axle with a multi-link suspension, but unlike the Wrangler, the front suspension is going to be independent. This is a wise move for Ford; IFS is the right answer for 95% of the questions asked of the Bronco both on and off road, and they don’t have to worry about a small but extremely vocal cadre of purists raising a ruckus like Jeep will when they inevitably have to switch the Wrangler over from a solid front axle. 

There Won’t Be a Traditional Transfer Case and 4-LO

This prediction is more speculative than some of the others, but images circulating on the interwebs point to a manual gearbox with a ratio labeled “C” on the shifter rather than a separate lever/button to engage low range. Ford has plenty of experience with 4WD systems, from full time to shift on the fly to manually-selectable, but this is a new twist. In addition to a ‘creeper gear’ you can also expect selectable locking for the front and center differentials, and either a limited slip or locker for the front as well. 

Want a V8? That May Be a Long Wait for a Train That Doesn’t Come

Way back in the early 1990s, Ford decided that the future of their powertrains lay in the direction of smaller-displacement engines with more sophisticated designs to replace their tried-and-true pushrod V8 design. While there’s much to be said about whether overhead cam V8 engines were the right idea for their trucks as well as their passenger cars, they have remained steadfastly devoted to the idea of high technology instead of raw cubic inches.

On the dyno, either engine choice for the new Bronco absolutely murders the old SBF V8…

For the Bronco, it’s very likely that the workhorse “base” engine will be the 2.3 liter EcoBoost 4-cylinder delivering something in the neighborhood of 270-280 horsepower and 310 pound-feet, biased toward low-end horsepower and torque. The optional upgrade is likely to follow the rest of Ford’s truck lineup with the twin-turbo 3.5 liter EcoBoost V6, producing around 375 horsepower and 470 pound-feet. 

On the dyno, either engine choice for the new Bronco absolutely murders the old SBF V8, but buyer acceptance is going to come down to whether the market they’re trying to court (both in terms of people with fond memories of Broncos past, and would-be Jeep Wrangler owners cross-shopping) believe that a turbocharged small-displacement engine is the right solution. Engine calibration is going to make or break the success for the new Bronco among shoppers who are looking for off road competence, and the benchmark Wrangler JL offers not only a standard naturally-aspirated 3.6 liter V6 gasoline engine rated at 285/260, but an optional 2.0 liter turbo inline four with 270 horsepower and 295 pound feet, plus a turbocharged 3.0 liter EcoDiesel that delivers an estimated 260 horsepower and 442 pound-feet.

Offering a 5.0 liter gasoline V8 based off the current Coyote architecture would seem to be an attractive option for Ford, should customers desire a NA engine over the EcoBoost 4 and 6 cylinder powerplants, but considering how the wind has been blowing with their Raptor models, a hopped-up EcoBoost V6 seems more likely as a future ‘premium’ engine upgrade.

It’s Ford’s chance to show the world what they can do when they’re turned loose to compete with the current heavyweight champ.

The Devil in the Details

While we feel we are on pretty solid ground with these predictions, Ford has kept most of the details for the new Bronco very close to the vest. You can be sure that every engineering, styling, and marketing decision for the new model was vetted against the Wrangler archetype, though – the company has a clear vision of what they’re trying to accomplish with 2021 Bronco, which is something pretty rare these days when focus groups, shareholder opinions, and low-risk strategies dominate new car and truck designs. That’s what’s really exciting about the upcoming reveal. It’s Ford’s chance to show the world what they can do when they’re turned loose to compete with the current heavyweight champ.

The Rotary Revolution

In the 140-plus years since the modern internal combustion engine was invented, there have been a countless variety of different designs; 2-, 4-, and even 6-stroke cycles, inline, vee, W, X, H, and horizontally opposed cylinder arrangements, combustion chamber shapes ranging from flathead to hemispherical, and all manner of the different valve and camshaft configurations. The technological pressure cooker of wartime development brought forth oddities like the Great War’s rotary piston engines that spun the entire crankcase and cylinders around a crank firmly bolted to an aircraft’s nose. Those evolved into radial engines with stationary crankcases, culminating in massive 28-cylinder beasts displacing more than 4,000 cubic inches and delivering 4,300 horsepower by the end of the Second World War. Then, there was the truly strange “Deltic” design that arranged three crankshafts at the corners of a triangle, each powered by pistons that moved in opposition to each other, with no cylinder head at all.

It’s the sort of mechanism that feels like it was reverse-engineered from a crashed UFO, or taken straight from the Old Testament book of Ezekiel compared to a piston engine.

But whatever form even the strangest of those engines took, they all shared one design feature that Nikolaus Otto, the creator of the first modern internal combustion engine, would instantly recognize: A reciprocating piston moving back and forth in a cylinder bore, translating linear motion into rotation via a connecting rod and crankshaft. It’s a concept so simple and elegant, but so well-suited to the task that the overwhelming majority of internal combustion engines have employed it. Though they’ve grown in sophistication over the years with new materials and manufacturing techniques, decent piston engines can be made using very basic design skills and fairly simple machine tools. Because of how difficult it is to build a “better mousetrap” than a piston engine, almost every attempt has fallen short in one way or the other and been forgotten, with one notable exception: The Wankel rotary.

Thinking Outside the Box (Or Tube, in This Case)

First conceived in the late 1920s by German engineer Felix Wankel, despite having only two main moving parts, the rotary engine’s principle of operation isn’t intuitive at first glance like a conventional piston engine. The Wankel goes through the same four stages as a piston engine – intake, compression, combustion, and exhaust – using a bowed triangular rotor that moves around an oval housing (technically, an ‘epitrochoid’ shape, a word that means “you didn’t do well enough in your Trig class to understand what’s going on here”) on an eccentric shaft. A fixed gear on the side of the housing engages a ring gear on the inside of the rotor so that for every complete turn of the rotor, the eccentric shaft turns three times.

It’s the sort of mechanism that feels like it was reverse-engineered from a crashed UFO, or taken straight from the Old Testament book of Ezekiel compared to a piston engine. But the important thing is that the motion of the rotor within the housing causes the volume between the rotor face and housing to vary in a useful way, just like the rise and fall of a piston in a cylinder bore. Though Wankel filed his first patent for the rotary engine in 1929, it would take until 1957 for him to develop a working prototype while employed at the German NSU car company. His original prototype, while using the same general principle as the rotary engines we are familiar with today, was somewhat more complex with a rotor housing that spun inside an outer casing as well as the moving rotor on the interior.

Working in parallel (and without Wankel’s knowledge), NSU engineer Hanns Dieter Paschke also developed a working prototype stationary-housing rotary engine in 1957, and it would be this design that evolved into a practical car engine. Intrigued by the potential of the Wankel, auto manufacturers from around the world, including AMC, Ford, General Motors, Citroën, Mercedes-Benz, and even Rolls-Royce licensed the design to develop their versions, but in the end, Mazda was the only company to produce Wankel rotaries in any significant quantity. While the rotary had some significant advantages over conventional piston engines, it also had several drawbacks that were inherent to the design, plus several non-trivial technical hurdles to overcome before it was suitable for mass production.

You Win Some, You Lose Some

On the positive side, the Wankel ran with a smoothness that no piston engine could match. In television ads, Mazda used a catchy folk song with the chorus, “Piston engine goes (boing, boing, boing), Mazda engine goes ‘hmm’” to emphasize that attribute. The lack of reciprocating parts also meant that Wankels could safely turn RPM numbers that would float the valves on any conventional production line piston engine, limited only by the strength of the rotor and stationary gears and what the engine-driven accessories like the alternator and water pump could endure.

In terms of size and weight, rotaries are extremely compact and light for their power output. Though they commonly had their displacement described in terms of a single chamber on each rotor’s volume (making the ubiquitous Mazda 12A and 13B rotaries nominally 1.2 or 1.3 liters), the fact that there were three such chambers for each rotor made them perform more like an engine with twice the stated displacement.

…NSU’S struggle to build production rotaries that didn’t blow bits of apex seal out the exhaust was the major reason the Wankel quickly gained a reputation as an unreliable engine.

As far as drawbacks go, the first problem facing anyone trying to make the Wankel practical as a production car engine was creating effective and durable seals. In a conventional piston engine, the gap between the piston and the cylinder wall is sealed by a ring package that uses a combination of gas pressure directed into the ring lands and the pressure differential between the area above and below the ring itself to dynamically load the top ring and keep it at the proper tension. While modern piston ring design and the materials used have become very complicated and sophisticated, simple iron rings with a square profile will do the job quite nicely if you’re not trying to squeeze out that last few percentage points of power and efficiency. As a bonus, circular rings are a piece of cake to manufacture to precise tolerances as well.

This isn’t the case with a Wankel. A look at how the rotor oscillates in the housing tells you that you’re going to need three long, gently curved seals on either side of the rotor, plus three seals at the apex of each point of the rotor’s triangle to separate the individual “combustion chambers” from one another. While the side seals didn’t turn out to be a big deal, coming up with apex seals that were durable enough for a production car ended up being a real challenge. NSU’s struggle to build production rotaries that didn’t blow bits of apex seal out the exhaust was the major reason the Wankel quickly gained a reputation as an unreliable engine.

Mazda managed to develop reliable apex seals for their rotaries, but another challenge came from the fact that unlike a piston engine, where the cylinder bores are continuously lubricated by oil slung from the connecting rod bearings as the crankshaft spins, there’s no convenient way to get lubrication to the apex seals. The solution came from injecting small amounts of engine oil into the intake airstream, providing the same end result as premixed fuel and oil for a 2-stroke dirt bike or chainsaw.

In the end, rotaries proved to be more trouble than they were worth, even for Mazda, at least in terms of production car use.

Unfortunately, about the same time Mazda got that issue figured out, the oil crisis of 1973 sent fuel prices skyrocketing, and in the US, emissions standards began to be taken seriously. This double whammy hit the Wankel where it lived – although the engines were efficient in terms of size and weight for their power output, their Brake Specific Fuel Consumption (the amount of gas required to produce a particular amount of horsepower) was poor compared to a conventional piston engine and having to constantly inject a bit of oil mist into the engine inevitably lead to unavoidable higher hydrocarbon emissions.

Thermodynamics Is a Harsh Mistress

As it turns out, a piston engine with cylindrical bores is about the best practical shape for keeping heat contained inside the combustion chamber, since it has the least surface area for any given volume. The arcane geometric wizardry that makes a Wankel even possible also dictates that the constantly changing combustion chamber shape is going to have a lot of surface area for the engine’s displacement, which means that a disproportionate amount of the heat energy from burning fuel is going to end up slipping away into the rotors, side housings, or endplates instead of doing useful work. That unavoidable fact meant that rotaries would never be able to match a conventional piston engine’s fuel economy pony for a pony, even when installed in a car optimized for the Wankel’s lightweight.

There are other quirks to rotary engine design as well – because of that oddly-shaped combustion chamber, Mazda used two spark plugs per rotor with staggered ignition timing to make sure the air/fuel charge burned as completely as possible. Additionally, variable cam timing and/or valve lift can dynamically change the characteristics of a piston engine’s combustion cycle, but a Wankel engine’s intake and exhaust timing are fixed, much like a valveless two-stroke engine, dictated by the position of the ports on the side housings and periphery of the center housing.

The Wankel Legacy

In the end, rotaries proved to be more trouble than they were worth, even for Mazda, at least in terms of production car use. The end of the line for the venerable original 13B, which remained in production for an astonishing three decades, came with the end of FD RX-7 production after the 2002 model year. By then, the 13B-REW had evolved into a twin-turbo 280 horsepower plumber’s nightmare of vacuum lines and emissions control hardware that was far removed from the simplicity promised by the original Wankel design. Its successor, the naturally-aspirated 13B-REW RENESIS found in the 2003-2013 RX-8, improved emissions, and fuel economy via a radical rework of the exhaust port location and truly heroic engine control calibration efforts, but ended up falling short of ever-more-restrictive emission limits in the US and Europe nonetheless.

…the real legacy of Herr Wankel’s inspired engine design is the unmistakable sound of a three-rotor peripheral port engine banging against the rev limiter at the race track, sounding like a cross between a machine gun and the end of the world.

Mazda continues to experiment with Wankel engine design, showcasing things like hydrogen-fueled rotaries that burn much cleaner than gasoline-powered designs in concept vehicles, but it’s unlikely that we’ll ever see the widespread enthusiasm for this radically different kind of internal combustion engine as we did in the late 1960s and early 1970s again. For niche applications where a high power-to-weight ratio and compact dimensions are critical, the rotary will retain its popularity, but the real legacy of Herr Wankel’s inspired engine design is the unmistakable sound of a three-rotor peripheral port engine banging against the rev limiter at the race track, sounding like a cross between a machine gun and the end of the world.

Old School Cool: All About Air Cooled Engines

It’s an unfortunate reality that internal combustion engines are inefficient, turning more than half of the energy from every drop of fuel burned into waste heat instead of forward motion or sweet, sweet tire smoke. Much of that lost energy goes into the exhaust, but in order to keep things like cylinder heads, pistons, and engine blocks in a temperature range where they can operate reliably, every engine has to have some way to move waste heat away from the metal and into the air.

Air-cooled engines have been around for basically forever; they’re simple, light, and less complicated than liquid cooled designs, and yet aside from some very specific niche applications, it’s hard to find any large-displacement air-cooled engines in production today. In the US market, most people would be hard-pressed to identify any air-cooled car engines other than the one used by VW for decades across their entire model line, from Beetle to Bus, Porsche’s flat-six 911 powerplants, and perhaps the Corvair. In the motorcycle world, air cooling held on for a lot longer, but even BMW and Suzuki eventually gave up on fins in favor of water jackets for their street bikes.

Battle-Tested

As with so many important aspects of piston engine technology we take for granted today, the competition between air and water cooling saw its most intense period of development during the Second World War. The original 1903 Wright Flyer, the first practical aircraft, used a four-cylinder water-cooled engine (although it had no radiator, relying on boiling off its limited supply of water during the short duration it had to run) and during the Great War, both air-cooled rotary engines (no, not Wankels – that’s a story for another time) and liquid cooled inline engines rapidly developed.

By the late 1930s, aircraft engines, which needed to be both light and powerful, had evolved into two basic forms: Watercooled inline or V designs, and air-cooled radials. The legendary Merlin that powered the P-51 Mustang, and the Allison V-1710 that was installed in pairs in the P-38 Lightning were both liquid cooled, while fighters like the Wildcat, Hellcat, Corsair, and Thunderbolt all had big, round air-cooled radial engines. Neither approach to engine cooling held a clear advantage (as a matter of fact, it was actually possible for the extremely clever radiator or cooling fin ductwork to generate net thrust from waste heat, though the effect was almost too small to measure) and things mostly came down to packaging within the airframe and streamlining. There, the liquid cooled engines had the advantage of a smaller cross-section, versus simplicity and the lack of a vulnerable radiator for the air cooled radials. By war’s end, both types of engines were capable of more or less the same peak power output and had similar power-to-weight ratios.

Cars Aren’t Airplanes Though…

Perhaps the world’s best-known air-cooled engine (and certainly the most widely-produced), the iconic Volkswagen flat four, was conceived during that same tumultuous time as an inexpensive and compact powerplant for Ferdinand Porsche’s “people’s car.” While the design for the Volkswagen Type 1 was set by 1938, it wouldn’t be until a decade later that civilian versions were manufactured in any numbers in post-war Germany. Czechoslovakia’s Tatra had also made a number of air-cooled cars before the war, and continued all the way through the late 1990s (and even still makes air-cooled heavy trucks today) and FIAT and Citroën embraced these kinds of engines in their small, economical post-war vehicles as well.

The only major US domestic manufacturer to put an air-cooled engine into mass production in the modern era was Chevolet, for the 1960-1969 Corvair. These flat-six engines were actually very successful, though the car they were designed for suffered from the first wave of consumer safety activism that would later target Pinto, Audis, and GM trucks for design flaws that made them somewhat more dangerous (though not greatly so) than their contemporaries. Chevy’s air-cooled flat six got thrown out with the bath water, and all subsequent GM engines would rely on liquid cooling.

Of course, it would be impossible to discuss air-cooled auto engines without mentioning the wildly successful Porsche flat-6, which powered the 911 family all the way through the 1998 model year before finally being replaced by a water-cooled design with a similar layout. The ongoing success of that engine family showed that it was certainly possible to create a completely modern, extremely powerful and reliable engine that didn’t need coolant. So why the switch?

Modern Problems Require Modern Solutions

The dominance of water-cooling in present day automotive engine applications comes down to a few main factors. First, there’s the issue of performance. Though Porsche’s air-cooled flat six (as well as innumerable air-cooled motorcycle engine designs) proved that it’s possible to build engines that are very powerful and reliable without coolant jackets, and more importantly water circulating through the cylinder head, as specific output climbs it becomes harder and harder to control hot spots in the combustion chamber using air cooling alone.

The exhaust valve and port area is one particular trouble spot – without coolant flowing through adjacent passages, it’s hard to move the heat build-up from this area in particular out to the atmosphere, no matter how much cooling fin you throw at the problem. There simply isn’t enough room to accommodate the necessary surface area on the head for adequate heat rejection, and issues arise for cooling the cylinders that aren’t first in line for airflow.

Pistons are another potential issue, as they must first transfer the majority of their excess heat through the ring package and into the cylinder wall before the engine block can take it away, whether it’s water- or air-cooled. Even in water-cooled high performance engines it’s not uncommon to use oil squirters directed at the underside of the pistons to help cool them, and the problem is compounded in air-cooled engines that often use very large amounts of oil circulating in the engine and pumped through an external radiator to assist in temperature control.

Better control over cylinder head and piston crown temperatures allows more leeway before preignition (and the engine damage that goes with it) sets in, making water-cooled designs generally less sensitive to fuel quality and more tolerant of high compression ratios or boost. This factor alone weighs heavily in favor of abandoning air cooling for max-performance production engines.

Another increasingly important consideration is tailpipe emissions. The industry has done an incredible job reducing pollution over the last four decades, with emissions control strategies that have a surprisingly small performance downside. The last untapped source of potential improvement, though, was engine startup. Because engines run so clean once they’re up to operating temperature, the majority of tailpipe emissions left to deal with happen during the cold start process. This is why current best practices close-couple a catalytic converter to the cylinder head in the exhaust manifold collector, to reduce the time it takes for the catalyst to ‘light off’ and start doing its thing.

The same is true with ECU mapping during cold starts. Additional fuel must be added – back in the day, we had this thing called a choke that manually blocked airflow through the carburetor and enriched the mixture to the cylinders, but now it’s all handled via computer, with more fuel called for from the injectors until the engine reaches normal operating temperature. An air-cooled engine, even with modern fuel injection, is still slower to get to that point because the cooling system is always ‘on,’ but a water-cooled engine with a thermostat can keep the radiator out of the loop until everything is up to temperature.

Although it’s certainly possible to build an air-cooled engine with baffles to control the airflow past the cylinders (and indeed, this is a ubiquitous feature on light aircraft engines like the Continental and Lycoming flat-four and -six engines that power practically every Cessna, Piper, Beechcraft, and Lancair in the world today), the quick warm-up and precise in-operation control of temperature gives liquid-cooled engines an enormous advantage when it comes to clean tailpipe emissions, and it’s the main reason why Porsche (and to a lesser extent, Volkswagen) eventually adopted it after a long history of successful air-cooled engines.

Finally, there’s the issue of noise. This may not seem like a big deal at first, but many countries have adopted noise standards that don’t just include the exhaust – intake and other engine noise all count toward the maximum decibel level a vehicle can legally produce. Liquid-cooled engines are inherently quieter than air-cooled ones, partially because of the dampening effect of the water jacket around the cylinders, and because there are no cooling fins directly attached to the reciprocating parts of the engine that can act as resonators, amplifying certain frequencies.

Even the notoriously atavistic Harley-Davidson motorcycle lineup, one of the last strongholds of air-cooled engine technology for road vehicles, is reluctantly moving toward liquid cooling. Their most recent design, the “Milwaukee-Eight,” circulates oil through passages in the cylinder heads, though the cylinder barrels remain air-cooled. It’s only a matter of time until they join their Japanese V-twin competitors and fully embrace water-cooled designs that retain vestigial cylinder fins for cosmetic purposes, if for no other reason than noise limits. After all, every decibel saved in mechanical noise from the engine itself is another decibel available for that all-important exhaust note, and while it’s hard to keep your customers from swapping to louder pipes once they get their bike home, it’s not practical short of complete replacement to go back to an air-cooled engine design.

Like many different technologies that were competitive for quite a while, but eventually fell out of favor for the majority of users, air cooling has seen its time in automotive applications come to an end. Nevertheless, for other situations where light weight and simplicity are still the main priorities (like piston aircraft engines), they’ll remain in production and use for the foreseeable future, as they remain a viable solution to those particular needs. And of course, as long as there’s a single gallon of gas left on earth, somebody somewhere will be using it to fire up the 1600 flat four in their lovingly-maintained VW Super Beetle that still runs like a top.

Understanding Independent Front Suspension (IFS)

Early 4 wheel drive trucks used a solid axle up front because it was simple, and strong. However, the solid axle has downsides. One of which was the ride quality. Anything that disturbs one side of the axle affects the other side too. With an independent suspension, both sides work independently from each other. IFS was designed in part to provide a smoother ride, but like everything else on a vehicle; it has its strengths, and weaknesses; we’ll explore both.  

In order for the axles to articulate when the suspension moves up and down, the IFS uses constant velocity joints (CV’s). The CV’s get their name from their function. As they move, they maintain a constant velocity unlike your standard cardan or universal joint. CV’s do not need to be timed like a universal joint, and opposing CV’s can work at different angles without causing a vibration. 

CV’s are constructed from a splined “star” that slides over the splines on the axle shaft. The star has deep grooves on the outside diameter that provide a bearing race for several large ball bearings (typically 6). There are other designs that use square parts with needle bearings, but the most common CV’s use round balls. The round balls are contained in a ring that has holes through it where the ball bearings sit. The ring is called a cage. The cage and bearings then fit into the outer housing that has the same deep grooves of the star in its inside diameter. The star drives the bearings that in turn drive the outer bearing housing. The cage simply holds the ball bearings in place.

The result is an assembly that drives the axle shaft while allowing it to articulate in any direction. There is a limiting factor to the articulation; a maximum angle that the CV can move. If the axle shaft exceeds that limit it can bind, or come apart. All that motion of the balls creates a lot of friction (heat), so proper lubrication is a must. That’s why it’s also critical to keep dirt out of the CV; that is the job of the CV boot. The boot needs to flex with the CV while keeping the grease inside, and water, and debris out. Boots are made from rubber, silicone, or plastic. Heavy duty leather boots are also available, but those are mostly used for racing. One of the shortcomings of CV’s is when the boot gets damaged, the grease escapes, and it doesn’t take much foreign matter to destroy the CV joint. 

An IFS has more moving parts, and more points of failure than a solid axle. Each a-arm will have a pivot or two with a bushing on the chassis end, and a ball joint or spherical bearing at the upright that allows the suspension to move up and down and to turn at the same time. All these points create friction so they will wear over time, and can fail. There is also a packaging problem with IFS. Fitting shocks, steering, and axles into a space tight enough to still allow tire clearance at full lock can be daunting. The other issue is the CV’s maximum angle. It will limit the amount of suspension travel available.

Most independent suspensions use an upper and lower a-arm, and a spindle or upright as many call it. The exception to this is Ford’s Twin Traction Beam Suspension, or TTB. The TTB is unique in that it has what is typically a solid axle with a universal joint in the long side axle which allows both sides of the housing to articulate. It’s a solid axle with a pivot in the middle. It does offer independent motion of both wheels, but it has more of the properties of a solid axle than an independent suspension using a-arms, and CV joints. 

The independent suspension has a differential just like the solid axle, but with CV’s on both ends. The differential is mounted to the chassis which decreases the unsprung weight of the vehicle. Unsprung weight is the weight of the moving components of you suspension. Sprung weight is the weight of the vehicle that the suspension is holding up. The less unsprung weight you have, the less work your shocks need to do to control the suspension. Your suspension is much more responsive to the terrain without needing huge amounts of damping in the shocks. When combined with fewer tendencies to transfer suspension inputs to the other side of the vehicle like a solid axle does, the result of IFS is a much more comfortable ride. 

When designing an IFS, room for the differential housing in the chassis has to be taken into account. The front end already has tons of stuff occupying space like the engine, fan, and radiator. Some designs simply drop the chassis down in the center of the frame to mount the differential. This can cause ground clearance problems. Instead of an axle that can move, you have solid frame making contact to the ground or rocks. If the IFS is properly designed, it can actually increase ground clearance in front, but moving the differential up too high can lead to excessive angles on the CV joints, a definite limiting factor. That’s why many rock crawlers prefer a solid axle in front. The solid axle will lift the entire front end up and over rocks. With an independent front design, you need to keep the tires on the rocks as one side of the suspension will go up and over the rock, while the chassis and opposite side are not affected. When it comes to the rocks, the solid axle has some advantages over IFS. 

When talking about an IFS you also need to discuss the steering. Most IFS designs use rack and pinion steering. The rack is a long rectangular piece with straight gears cut into it. It is held in mesh with a pinion gear that comes in perpendicular to the rack. As the steering wheel is turned, the pinion gear moves the rack back and forth. On each end of the rack are steering shafts that connect to the upright on the other end. Care must be taken to keep the length and angle of the steering shafts similar to the a-arms. If the motion of the steering shafts are not on the same arc as the a-arms, you will experience bump steer. Bump steer is when the up and down motion of the suspension pushes or pulls on the steering shafts causing the wheels to turn, or toe in or out. A drawback to the rack and pinion is that when a load is put on a steering shaft, that load goes to the teeth on the rack, and the pinion gear at the point of contact. If you continuously encounter these loads, the teeth on the rack can hammer against the pinion gear causing it to wear out or break.

Breakthroughs in CV joint designs, as well as other IFS parts and assemblies have pushed 4 wheel drive IFS to high levels of durability.

It was already mentioned that the IFS gives a smoother ride, it has other attributes as well. Because of the way the upper and lower a-arms travel in an arc, the upright maintains nearly perfect camber throughout the suspension travel. Where a straight axle will have the tires on an angle when it articulates, the IFS will keep the tread of the tire parallel to the ground. That maximizes the contact patch of the tire, giving you maximum traction for acceleration, braking, and steering control. It also saves the sidewalls of your tires from possible damage. Because both tires move independently, and with less input on the chassis, the vehicle tends to be more stable; especially at high speeds. Both tires are free to move up and down, and remember there is also less unsprung weight, so the vehicle remains level and constant. With more traction, and better steering control, there is less understeer in the corners. Understeer is when the vehicle resists steering input and the vehicle momentum overcomes traction. It causes the vehicle to push straight ahead in the turn. With an IFS you can push harder into the turns, and accelerate sooner because the front will turn better. While the straight axle might be better suited to slow speeds in the rocks, the IFS shines at high speeds in rough terrain. Impacts that will upset a straight axle suspension will be soaked up with ease by the IFS. 

Breakthroughs in CV joint designs, as well as other IFS parts and assemblies have pushed 4 wheel drive IFS to high levels of durability. Pro-4 racing on the track, and Ultra4 racing offroad has refined the parts needed to apply the horsepower and torque that is available today. So much so that Unlimited Trophy Trucks, the biggest and baddest trucks racing in the desert, are now being built with 4 wheel drive. The drive assemblies are so reliable that the extra complexity is worth it. The benefits include less possibility of getting stuck in the silt, quicker acceleration out of the turns, being able to drive deeper into the corners, and less wheel spin so your tires may last a little longer. New designs with portal axles to reduce CV angles, and provide additional gearing options will push performance ever farther. There have been several 4 wheel drive Trophy Trucks in the past, but they seemed to be burdened by the complexity of 4 wheel drive. Now that the bugs have been worked out, 4 wheel drive IFS has become the wave of the future.   

Spray to Play

Nitrous and the N2O Need-to-Know

Call it spray, squeeze, juice, the bottle, or simply “naws” – nitrous oxide is one of the high performance world’s most popular power-adders, as well as being the most misunderstood. Because it’s easy to conceal a nitrous oxide injection setup, many consider it to be ‘cheating.’ Because it’s easy to give an engine more than it can safely handle, many consider it dangerous to your car’s health. Today, we’re going to take a quick look at how it works, bust a few myths, and tell you what you need to know about N₂O.

Nitrous oxide is a chemical compound consisting of two nitrogen atoms bound to a single oxygen atom. First synthesized in 1772 by Joseph Priestly (who was the guy who arguably was the first chemist to discover and isolate oxygen), by the mid-1800s its effects on human consciousness had led to its use as both an anesthetic for medical purposes and a party drug, both of which continue to this day.

It took another century for its usefulness as a power-adder for piston engines to be widely recognized; during the Second World War, many Luftwaffe fighter aircraft were fitted with what was referred to as the GM-1 system of nitrous oxide injection that greatly improved engine performance at very high altitude. Post-war hot rodders in the US made sporadic use of the gas, but in the late 1970s, the aptly-named Nitrous Oxide Systems (or NOS) company popularized it by producing the first widely-available kits and components that made it relatively easy to use without an engineering degree.

How Nitrous Works

People will often say that an engine is “like an air pump” – while that analogy is useful to a point, a better analogy would be a forge. Pump more air into the forge with bellows, and the fire gets hotter and more intense. The energy an engine can produce is directly related to how much fuel it can efficiently burn, and in order to create more horsepower, you have to burn more fuel, more quickly. In a high-performance naturally-aspirated engine, multi-valve cylinder heads and high RPM do the job of rapidly combining fuel and air into a mixture that can be ignited and turned into pressure to move the pistons. In a turbocharged or supercharged engine, a mechanical compressor forces additional air into the cylinders for every combustion cycle, and the additional air allows more fuel to be burned and converted into useful work.

In an engine with nitrous oxide injection, instead of increasing the rate of combustion events per second, or forcing more outside air into each one of those events, the composition of the intake air gets changed. The normal air we breathe is about 21 percent oxygen, give or take, while nitrous oxide brings one oxygen atom to the party for every two nitrogen atoms – about a 12 percent increase in the oxidizer available to burn more fuel.

“Why not just use pure oxygen instead?” you might ask. The answer is that nitrous oxide has another trick up its sleeve. Because it takes energy in the form of heat to decompose it into nitrogen and oxygen molecules, using N₂O as an oxidizer has a ‘buffering’ effect. At around 1,050 degrees F inside the combustion chamber, the oxygen is liberated, but not before absorbing some of the heat of combustion to power the reaction, slowing and controlling it. Pure oxygen fed into an engine will cause something more like an explosion than a controlled flame, but nitrous oxide is well-suited to the task of burning more fuel, without an uncontrolled reaction.

Nitrous oxide also has the benefit of cooling the ‘normal’ intake air charge as well. Stored as a liquid under pressure, when it’s released into the intake tract it flashes to a gaseous state, and the energy required for this phase change super-cools the air around it. This increases the density of the intake charge, delivering more air to mix with the available fuel and further adding potential power.

Nitrous System Terminology and Technology

There are two basic kinds of nitrous oxide systems: “dry” and “wet”. Dry systems only add nitrous oxide to the intake charge, while wet systems provide both N₂O and additional fuel. Dry systems were developed first, and relied on carburetors or mechanical fuel injection calibrated to run very rich when the system wasn’t in operation, so they wouldn’t be dangerously lean when the nitrous began to flow. Modern dry systems are a different story – they’re typically connected to an electronic fuel injection system that can provide the desired amount of additional fuel on command upon activation.

Wet systems are designed in a way so that when the system is activated, a calibrated dose of both fuel and nitrous oxide is delivered to the intake airflow at the same time. Both types of systems can introduce nitrous or the nitrous/fuel mix at a single point in the intake plenum, through a plate with spray bars or slots, or via individual nozzles located in each cylinder’s intake runner.

Nitrous oxide is stored in a self-pressurizing tank, with a capacity measured by the weight of its contents – ten and fifteen pound tanks are the most common. The tank is partially filled with nitrous oxide that is in a liquid state, topped by nitrous oxide gas. A siphon tube extends down to the bottom of the tank and leads to a valve that supplies the system. The pressure in the tank is determined by its temperature, and as nitrous flows out, some of the remaining liquid “boils off” inside the tank. To maintain temperature, a thermostatically-controlled electric heater can be used; sometimes you will see racers use a propane torch to heat a bottle, but this is an extremely dangerous practice as it can lead to weak spots in the tank that may not cause it to blow up on the spot, but that can lead to it catastrophically failing in the future when it is being refilled.

Nitrous flows from the valve up to the engine bay, where a solenoid (an electrically-operated on/off valve) controls the activation of the system. Wet nitrous setups will have a solenoid to control the flow of additional fuel as well, which is activated by the same circuit as the nitrous solenoid. One popular addition to the nitrous plumbing is a “purge solenoid” located adjacent to the main nitrous solenoid – by momentarily opening it, gaseous nitrous oxide is purged from the supply line and liquid is brought all the way up to the main solenoid, so that when the system is first activated it won’t briefly run rich.

Past the solenoids, the nitrous (and fuel in a wet system) proceeds to the plate or nozzle where it will be injected into the engine. At the connection to the plate or nozzle, a ‘jet’ is inserted inline to regulate the flow. Jets are made from brass, stainless steel, or other similarly durable materials and have small, very precise holes drilled through them. These orifices, measured in thousandths of an inch in diameter, are used to calibrate the oxidizer and fuel mixture. System manufacturers provide charts that explain, “With this nitrous jet, and this fuel jet, your engine will produce this much extra horsepower.”

It’s worth noting that the horsepower provided by a particular jet combination is constant, whether the engine is a 1.6 liter 4-cylinder or a 500 cubic inch big block V8, and it’s not dependent on engine RPM either. “100-shot” jetting is going to be very, very hard on a small four-banger, but is usually going to be OK with a large displacement eight cylinder engine. Even the V8 is going to have a hard time digesting that much fuel and nitrous below 2,000 RPM, though, because there aren’t going to be very many combustion cycles per second to safely burn all that extra fuel.

To increase the safety of a nitrous system, it’s possible (and advisable) to include components like a ‘window switch’ that will prevent the system from operating below or above preset RPM limits, a fuel pressure switch that shuts things down before the engine runs too lean, and even sophisticated progressive and multi-stage controllers that can pulse the solenoids many times per second instead of leaving them wide open as well as actively reducing ignition timing to prevent detonation. This allows the user to create a customized power delivery curve for the nitrous assist instead of it being a simple on/off proposition. But all of that aside, the most important advice to a would-be nitrous oxide user is “don’t be greedy – follow the manufacturer’s recommendations.”

Because it’s so easy to switch jets in a nitrous system (sometimes known as ‘pill it till you kill it’), the temptation is always to step things up and see what happens. But when used as directed, nitrous oxide is a safe, inexpensive, and effective way to significantly increase the performance of almost any engine.

Exhaust 101

Everything You Need to Know About Exhaust

One of the most popular upgrades for any performance vehicle, from V8 Mustangs, Camaros, and Challengers through pickups and SUVs to “tuner” turbo cars is an aftermarket exhaust. Considering how common it is for owners to discard the factory pipes in favor of something different, we’re going to take a look (and listen) to the basics of exhaust systems from start to finish to highlight what you need to know. Whether you are looking for more horsepower, a better sound, or both, your bank balance and your neighbors will thank you for educating yourself before you strap on a new aftermarket exhaust. 

An exhaust system has to achieve a few primary functions – First (and most importantly from a performance standpoint), it has to efficiently move spent gasses away from the combustion chamber to allow room for a fresh charge of air and fuel to enter for the next power cycle. Second, it has to move those gasses to someplace that won’t dump a lot of waste heat in the engine compartment (Fun Fact: 40% or more of the heat generated during a car engine’s operation ends up going out through the exhaust) or asphyxiate the driver and passengers. Third, except for pure competition applications, it has to moderate the volume and sound quality of the exhaust noise. Finally, in modern OEM applications, it has to incorporate emission control systems to reduce the amount of pollutants released by the exhaust.

Understanding these functions is the key to understanding why factory exhaust systems are built the way they are, and knowing what the tradeoffs involved in modifying your exhaust will be. Let’s follow the path of a puff of exhaust from the cylinder to the tailpipe to see how all the components involved contribute to the process.

When the exhaust valve opens, hot, energetic, pressurized, but diffuse waste gas exits the cylinder and travels through the exhaust port and out of the cylinder head. Each cylinder has its own port, and those outlets are connected to each other by a manifold. In most OEM designs that manifold is made out of cast iron, which is a good choice for durability and keeping the overall size of the engine package small, but it can come with a performance penalty. To keep things compact, the manifold may have runners for each individual cylinder that are different lengths or even different diameters, and this offers performance part makers their first opportunity to find a few extra horsepower.

Current state-of-the-art engine designs often make things difficult for anyone trying to build performance headers…

A manifold made of tubular steel, referred to as a header, is a common performance upgrade. Individual runners, called “primary tubes”, carry exhaust gasses to a collector where the output of several cylinders combines into a single stream. The collector does a couple of things besides just simplifying the plumbing from that point on – it reflects pressure waves along the primary tubes back to the cylinder head, and it lets each cylinder “talk” to each other. By carefully designing the length of the primary tubes and the volume of the collector, a good header can actually flow more efficiently than an exhaust port that’s open to the outside world by letting the waves of high and low pressure work together from cylinder to cylinder to actively scavenge exhaust gas in the engine’s main operating RPM range. 

Current state-of-the-art engine designs often make things difficult for anyone trying to build performance headers; because of ever-increasing emissions standards, it’s very common to have a catalytic converter built into the factory exhaust manifold so that it gets up to operating temperature as quickly as possible to reduce the amount of pollution during a cold start. Some engine designs even combine all the exhaust runners into the cylinder head itself, eliminating the manifold entirely. And in the case of turbocharged engines, the cast exhaust manifold is usually (but not always) also the mounting point for the turbo. All of these factors will determine whether a performance header is a worthwhile upgrade, or indeed even an engineering possibility, for your particular application. 

Speaking of turbos, you’ll frequently see a component called the downpipe listed as a performance upgrade. This particular piece of exhaust plumbing connects the outlet of the turbine section to the down-stream parts of the system, and in some factory engine designs it’s a well-known bottleneck for exhaust flow. Turbochargers like having as little restriction at the outlet of the turbine as possible; this is what lets them extract energy from the exhaust and use it to spin the compressor on the intake side. A well-designed aftermarket downpipe can increase horsepower throughout the RPM range as well as reducing boost lag. 

For both forced-induction and naturally-aspirated OEM engines, the next stop is usually the main catalytic converter(s). In V6 and V8 RWD cars, they’re often incorporated into an X-, H-, or Y-pipe, while inline engines with a single header have a simple section of exhaust pipe that incorporates this emission control device. Back when catalytic converters first became necessary in order to meet tailpipe pollution standards, they posed a serious obstacle to performance, causing a major restriction to exhaust flow that the engine had to fight. Today, both factory and aftermarket catalysts take a very minimal toll on horsepower, and depending on how aggressively emissions laws are enforced in your neck of the woods, removing or defeating them can be very expensive if you happen to get caught. Ultimately it’s between you and your conscience if you decide to roll the dice, but the performance penalty for a catalyst-equipped exhaust is much lower than it was back in the day.

You’ll often see variations on the term “cat-back” in aftermarket exhaust descriptions – this usually means the system has no effect on emission controls and is legit in all 50 states (at least from a pollution perspective). Factory exhausts need to meet specific sound level limits, as well as being durable enough to not wear out during the car’s warranty period even in salt-encrusted rust belt states, while being as inexpensive as possible. A good aftermarket cat-back system will offer superior materials and construction – typically stainless steel – while being lighter than the OEM exhaust, and if it’s particularly well designed (and the factory system is particularly bad) it may even increase horsepower and torque. 

Mufflers use a variety of different engineering approaches to reducing and changing the sound of the exhaust. Solid or perforated baffles inside the muffler body can be used to suppress specific frequencies by reflecting sound waves back on themselves, and packing materials like fiberglass are sometimes employed to absorb sound energy, though if the muffler is poorly designed, they can get compressed or even blown out over time, compromising the effectiveness of the system. Mufflers with a “straight through” design typically give less flow restriction at the expense of less sound reduction than designs that force the exhaust to change direction or travel through multiple internal chambers. Even the overall size of the muffler plays a role in how it sounds – more internal volume gives the designer more opportunity to modify overall noise levels and tune out unwanted frequencies. 

Of course, the main reason to replace the factory resonator and muffler system is to get an exhaust note that you like better than stock, and this comes down to personal taste. The only advice we can give you in this respect is, if it’s in any way possible, find somebody who already has the cat-back aftermarket exhaust you are considering and listen to it in person. Video and audio clips on the internet are better than nothing, but they are no substitute for hearing it yourself. It’s also important to ask yourself if it’s something you can live with all the time if it’s your daily driver, and if your need to flex on everybody who pulls up next to you at a stoplight is worth your neighbors actively hating your guts. A good exhaust system is music to your ears, but there are plenty of people out there who have hung new pipes on their car but secretly wish they’d picked something else, no matter how much they tell their friends it’s exactly what they wanted it to sound like. 

The bottom line is that your exhaust system is one of the first things people will notice about your car, and one of the last things you want to get wrong. Make sure you educate yourself, get input from other people who have done the upgrades you’re considering, and be realistic about how much of a performance increase you can expect and how much additional noise you’re willing to live with to get it.

Leaf Springs vs Suspension Links

Let’s be specific, and talk about leaf springs versus suspension links with a solid axle. You may have a straight axle in one end of your 4×4 or both, and it could have a combination of links with leaf springs, all leaf springs, or all links front and rear. Both leaf springs and suspension links have their strengths, and weaknesses. Depending on several factors, either design might be right for you, so we’ll take a look at both. 

There are all kinds of link configurations in use. Links can take the form of radius arms, be used in a combination of 4 links, or 3 links, and include wishbones, or panhard bars to center the axle. There is even a unique watts link design, but it is rarely used on a 4×4 because of its limited suspension travel. The job of the links are to locate the axle; that’s it. Some designs will have the shocks and/or springs mounted to the link, but that’s an added function. The link’s main role is to attach the axle to the chassis, and allow it to articulate. 

Linked designs use a coil spring to support the weight of the vehicle. Coil springs can be mounted independently of the shock, or they can be combined in a coilover shock. The coilover shock is a fantastic design because it is compact, and easy to mount. There are no spring retainers or coil buckets needed, only a single bolt on each end. The distinction of a coil spring is important because a coil behaves much differently than a leaf spring. First let’s talk about spring rate. The amount of weight it takes to deflect a spring one inch is the rate of the spring. If it is 100 pounds then for each inch the spring is compressed, it generates 100 more pounds of resistance. To compress it 2 inches, it takes 200 pounds of force. If the coil is wound consistently throughout its length, then it is a single rate coil. Its spring rate is linear. The 100 pounds per inch does not vary. 

Linked designs use a coil spring to support the weight of the vehicle.

There are progressive rate coil springs too. They have a few closely wound coils at one end and then wider, equally spaced coils at the other end. The closely wound coils compress at a different rate than the widely spaced ones. Dual rate coil springs are used in some factory based designs. With coilover shocks, the way to create a progressive spring rate is to stack them together. A short stiff spring stacked on a longer, more flexible spring will give you a spring combination that changes rate as it compresses. It’s easy to swap coils to fine tune the rate. You can also adjust the spring rate by introducing preload to the coil spring or springs. If you compress the coil one inch in our 100 pound example, the resistance will already be 200 pounds while the vehicle is at rest.  

On a leaf spring, the rate is progressive due to the multi-leaf design. The more you compress it, the higher the rate goes. Leaf springs work together as a single unit. Each spring is designed to work with the next leaf in the stack. It’s much more difficult to adjust them without the entire leaf pack being removed, and disassembled. Leaf springs can also suffer from spring wrap. Under hard acceleration or braking, the spring can wrap around the axle causing the axle to twist. The twisting can negatively affect traction, and abruptly changes the pinion angle which strains the driveshaft u-joints. A linked suspension will resist this condition because the links don’t flex. With leaf springs, there is no way to introduce preload to the spring. For ease of tuning, the coil spring wins.    

Leaf springs have been used since roman times so they are well understood.

The use of a coil is a huge advantage in the link design, but a linked suspension is much more complicated than the leaf spring design; especially if you are retrofitting it onto an existing leaf spring vehicle. It will take extensive fabrication, and a good understanding of suspension geometry. If you are building a 4 link design, the links take up a lot of space which means you will be doing extensive cutting, and relocating to make room. Most people who do a link conversion in the rear cut the entire back half of the frame off, and rebuild it from scratch to work with the link geometry. You can also forget about hauling much in the bed as that space is now taken up by the upper links. It depends on the link design you are using, but typically the longer the links are, the more suspension travel you can get. The linked design also offers more articulation. These attributes affect other assemblies on your vehicle like the steering linkage and the drive shaft, so they all have to be designed to work together. From a purely performance standpoint, the linked design wins again. 

It would seem like a linked suspension is the way to go, so why are leaf springs still in use? Leaf springs have their own benefits that make them desirable. Leaf springs are simple to produce, and easy to mount. Leaf springs have been used since roman times so they are well understood. Not only do they support the weight of the vehicle, but they also locate the axle housing. They are very compact when compared with a link design. They are mounted towards the end of the axle housing for stability, so the room between the springs can be used for other components like the engine up front, and gas tanks in the rear. Those components can be located lower in the chassis to keep the center of gravity low to the ground. It also means that a truck bed or cargo area of an SUV can be roomier inside. Because of the leaf springs progressive spring rate, they are much better suited to supporting varying loads. If you drive your truck empty all week, but use a slide in camper on weekends, leaf springs can handle the variation with little or no modifications. The same goes for towing. The stability that a leaf spring design provides helps substantially while towing. 

If you want a performance based vehicle for rock crawling, or high speed running in the desert, a linked suspension is your best bet. If you need utility for towing, or hauling heavy loads, leaf springs are the way to go.       

LS Is More

Everything You Need to Know About Chevy LS Engines

Certainly, there were overhead valve V-8 engines before the 1955 introduction of the small-block Chevy but it was the combination of a high-performance, lightweight package that got the cognoscenti’s attention. It didn’t matter if you were a drag racer, an oval tracker or just a guy driving his ’55 on the street that ‘mighty mouse’ roared.

The Gen I small-block was manufactured by GM almost unchanged for almost 40 years, however, emissions and efficiency requirements dictated a redesign and in 1992 GM gave us the LT1 and soon after the first LT4. Unfortunately, it was merely a face-lift and despite a reverse cooling system and some high-swirl ports, the Gen II did not live up to expectations and struggled to meet its goals. It was obvious; therefore that some new, clean sheet thinking was necessary.

The sheet wasn’t exactly clean though. The list of ‘needs’ included: a simple, lightweight design with higher efficiency and lower emissions, reduced noise, vibration, and harshness. More power and improved quality went without saying and, it had to surpass the Gen I small-block.

GM engineers Tom Stephens and Ed Koerner are considered the fathers of Gen III (ironically, nobody takes credit for Gen II) and in fact, some engineering drawings were made of what Gen III might look like as early as 1991. Meanwhile, however, GM had purchased Lotus Engineering in England and was experimenting with a double overhead cam (dohc) V-8 that initially found a home in the Corvette Indy/CERV III concept cars. Built for GM by Mercury Marine, the LT5 was what they thought the future looked like.

According to Will Handzel writing in his excellent CarTech book How to Build High-Performance Chevy LS1/LS6 V-8s, a group of GM execs were asked in May 1992 to test two different Corvettes. It was a ‘blind’ test in that the execs didn’t know that one Corvette had a Gen II LT4 engine and the other had the dohc LT5. The results surprised everybody—the execs unanimously preferred the easy grunt of the Gen II pushrod engine compared to the high-tech Lotus engine. That settled it: Gen III would be a pushrod V-8, albeit a better pushrod V-8.

Built for GM by Mercury Marine, the LT5 was what they thought the future looked like.

Lucky for us gearheads, Ed Koerner, a former drag racer, was made Chief Engineer and Ed pulled heavily from his racing experience in developing the new engine saying, “We wanted something of simple elegance. An engine that incorporated refined race technology.” Everything from the long-skirt aluminum block for added strength to the lightweight plastic intake known internally at GM as the IARF or integrated air/fuel module indicated performance.

The 5.7L (345.7 ci) LS1 made its debut in the new C5 Corvette for ’97. The new design certainly set the Corvette world alight but I’m not sure that the hot rod world looked at the LS1 and it’s coil-on-plug arrangement with affection. It was kind of a funky, cluttered engine and not at all ‘clean’ like its predecessors. Nevertheless, one could not argue with the engine’s power-to-weight ratio. The block weighed just 103 lbs and produced 345 hp—not much by today’s standards but remember this was more than 20 years ago.

GM was quick to realize the LS1’s potential and in 1998 it was made available in the Camaro and Pontiac Firebird. The following year, 4.8L, 5.3L and 6.0L variants were offered in GM trucks. Of course, this proliferation and the realization that this was the small-block of the future caused the aftermarket to start making everything from dress-up to speed parts—a market was developing.

“We wanted something of simple elegance. An engine that incorporated refined race technology.”Ed Koerner

In 2001, GM upped the ante with the LS6 variant that was available in the Corvette and some Camaros and Firebirds. The LS6 had a slightly smaller bore at 3.465 in compared to the LS1’s 3.898 in. They both had the same 3.66 in stroke but the LS6 had a higher compression ratio (cr) at 10.46: 1 compared to the LS1’s 10.19:1. The intake manifold was also changed. As impressive as was the LS1, the LS6 ‘dropped-floor’ intake manifold has more volume, flows better, and doesn’t need an EGR valve because of an improved camshaft/controller combination.

Incidentally, the fuel injection system was new for GM. Previously, GM’s fuel injection systems were batch- or bank-fire systems, however, the LS1 was a much more sophisticated sequential system where each injector opened only once during a complete firing sequence. While this does not offer huge power increases, it does reduce emissions and improves low-rpm drivability.

With an ambitious program of continuous development and improvement, GM introduced the Gen IV in 2005.  The Gen IV program began with the 6.0L LS2 and went on to include the 6.2L LS3, LS9 and L92, and the 7.0L LS7. The big difference for the Gen IV is that the cam-timing sensor moved from the rear to the front of the block. And that, according to Mike Mavrigan writing in his book LS Gen IV Engines 2005-Present is the only major reason for the Gen IV designation.

In 2006, GM introduced the 7.0L LS7 in the new Z06 Corvette. This was a hand-built engine in the tradition of companies such as Aston-Martin. The LS7 had titanium rods, CNC-machined heads and a race-style dry-sump oil system. It produced 505 hp and was the most powerful naturally aspirated engine in the LS family.

Introduced in 2008, the 6.2L LS3 with a 10.7:1 cr produced a healthy 436 hp and became and instant retrofit favorite. Mick Jenkins at Mickspaint.com, Pomona, CA, just dropped one of these into Louie Atilano’s ’65 Chevy truck saying, “We’ve swapped a lot of LSs into 60’s vehicles and it an easy-enough process.”

Mick also likes the LSA that first appeared in 2009. “The LSA is a supercharged version of the 6.2L that stock produces 556 hp. We put one into Jeff Pont’s ’64 Lincoln convertible and Pauly Riviera added 1956 Lincoln MkIII valve covers and other accessories to give it a more retro appearance.”

Over at Steve Strope’s PureVisionDesign.com, Simi Valley, CA, they also dropped a supercharged LT4 into the ‘Novaro’ they are building for comedian Joe Rogan. The LT4 is based on the same Gen 5 small block foundation as the 6.2L LT1 naturally aspirated engine, however, it was the most powerful production engine ever offered in a General Motors vehicle. It was introduced in the 2015 C7 Corvette ZO6 and then came in the 2016 Cadillac CTS-V and the Camaro ZL1. The 6.2L LT4 produces 650 hp at 6,400 rpm and 650 lb-ft of torque at 3,600 rpm and is available as an off-the-shelf crate engine for far less than $14K. The answer to its power is a compact, lightweight, low profile, Eaton four-lobe, 1.7L supercharger that produces 9.4 lbs of boost. The LT4 produces 457 lb-ft of torque just off idle and 625 lb-ft of torque at only 2,800 rpm. In comparison, the V-12-powered Ferrari F12 Berlinetta produces about 28 percent less torque than the Z06, despite offering about 12 percent more horsepower and its peak torque isn’t achieved until 6,000 rpm. The LT4 maintains 90 percent of its peak torque v  or 592 lb-ft from 2,500 to 5,400 rpm.

According to Steve Strope, “The LS9 and the LT4 are similarly supercharged engines, however, in my opinion, the LT4 has the slight edge over the LT9 even though the latter makes more horsepower in stock form. The LT4 also has a 3-inch lower supercharger/intercooler than the LS9 and therefore makes it an easier swap. It’s just a more refined engine. Also, GM provides a factory-matched ‘Connect & Cruise’ engine and transmission harness that includes specially calibrated controllers and wire harnesses designed for retrofit installations in older vehicles.”

As you can see, it’s very difficult to get your head around the LS nomenclature—there are just so many variants from the ’97 LS1 all the way through the current LS376/525 that with a .525-inch lift, 226 (Inlet)/236 (exhaust) degree cam delivers 525 hp at 6,200 rpm and 485 lb-ft of torque at 5,200 rpm.

But wait, there’s more: Just around the corner is the latest Corvette C8 due for release on July 18, this year. Speculation calls for a naturally aspirated (na), entry-level, LT-1-based 6.2-liter V8 producing somewhere around 460-500 hp, however, the rumor is that there might be a dohc 5.5L V8 with a flat-plane crankshaft, possibly producing 600 hp. There are even rumors of a twin-turbo version producing 800 hp. We shall have to wait and see. Needless to say, the LS story is far from over yet.

Understanding Straight Axles

Many historians agree that the wheel was invented in 3500 BC. What doesn’t get mentioned is that a wheel needs an axle in order to carry any weight. That means the straight axle has been around for just as long. When the automobile came about, the need to transmit power through the axle led to the invention of the live axle. The car axle still needed to carry the vehicle weight, but it also had to transfer power to the wheels, so the live axle design made a lot of sense. Any time you can have a single component do multiple functions it’s an engineer’s dream. That’s why you can still find straight axles under cars and trucks today. There are plenty of independent designs in use, but when the load capacity goes up, the live axle gets called into duty. The straight axle design is popular because it has many attributes that can’t be beat.

Strength

If you look at the individual parts that make up the straight axle assembly you will see that they are large, and stout. The housing is a weight bearing assembly so the axle tubes are generally a large diameter. The physical size is needed to allow room for the axles inside, but they also give strength to the overall housing. As the weight capacity goes up, so does the diameter of the axle housing tubes. Some of the largest live axles available are the military 5 ton units. Their axle tubes are actually square. They have plenty of room inside, even for the 2 inch diameter axle shafts they use.

All the power from the engine goes down the driveline and through the axle shafts, so as the intended loads increase, so does the diameter of the axles. The center section that houses the gears is most commonly made from cast iron. It needs to keep the ring and pinion from deflecting under load. During acceleration, deceleration, and cornering, the ring and pinion sees forces from several directions. If the ring and pinion were able to move at all, the mesh between gears would vary, and create binding, and irregular wear.

Most live axles are the same design, but scaled up or down to fit the parameters. A small, lightweight suv will not need the same strength that a one ton truck or race vehicle requires. As the housing, axles, and gears get bigger, the remaining parts all need to increase in size as well. Because of the straight axles design, it is easy to attach suspension mounts, and to increase the axle housings strength with the use of thicker materials and/or additional gusseting. This gusseting can be pretty extravagant on some configurations, and many are works of industrial art.

As seen on some Ultra4 cars, the center section can be moved to either side of the housing. The rear engine cars locate the center section all the way over to one side due to the location of the drivetrain. Auto manufacturers vary the location of the center section. Ford likes to locate it on the driver’s side in front axle applications. GM puts it on the passenger side. In the rear, it’s common to locate the center section slightly off center to compensate for the pinion gear offset. That way the axle shafts can be the same length.  

Versatility and Simplicity

The straight axle is simple in design, and extremely versatile. It can be used with many different suspension configurations. Leaf springs, coil springs, Torsion bars, or coilover shocks can all be used with the straight axle to suspend the vehicle. With leaf springs, the spring eyes provide the attachment points to the chassis. A coil spring, or coilover shock does not locate the axle so many different designs exist to attach the straight axle to the chassis including radius arms in front, links, or trailing arms and a wishbone.

Links can be triangulated to center the axle, or a panhard bar will be needed to control side to side motion. Still another straight axle suspension design is the watts link. The watts link keeps the rear axle centered at all times, which is good, but because of its equal length links, and center pivot design, the suspension travel is limited. Offroad race trucks use a wishbone or triangulated design because they use an incredible amount of suspension travel; up to 30 inches or more on some Trophy Trucks. 

Performance

The straight axle is popular among rock crawlers because of the superior traction it affords. That traction is made possible because of the travel and articulation possible. We’ve already discussed the suspension travel possible, but articulation is also critical to maintaining tire contact with the ground. With a straight axle, as one side travels upwards, like when climbing over a rock, the opposite side is pushed down into the ground.

Both tires will be planted. In an independent design, as one wheel moves up, it lifts the entire front end. The opposite tire can be lifted off the ground when the travel limit is reached. Independent suspension travel is limited by the length of its arms, and the maximum angle possible from the CV joints.

With a straight axle, as one side travels upwards, like when climbing over a rock, the opposite side is pushed down into the ground.

The independent suspension is pivoting from the attachment point at the chassis. That distance from the pivot to the tire is less than half the width of the vehicle on a factory based truck. The straight axle will be pivoting at the opposite tire. That means the pivot point is as wide, as or wider than the truck. The longer the distance from the pivot point to the tire, the more travel you will have. Travel is the distance it can move up and down, Articulation is the distance between the tire moving up, and the opposite tire moving down. Suspension travel and articulation are related, but in the rocks, articulation is king.  

Downsides

The straight axle has some great attributes, but it also has some drawbacks. While one side of the axle affecting the opposite side is an asset in the rocks, it’s a drawback when it comes to a smooth ride. The entire axle is disrupted by input from either side. The strength afforded by those beefy parts comes with a weight penalty when it comes to unsprung weight. Sprung weight is the total weight of everything that is supported by your springs.

The more unsprung weight you have, the harder it is for the shocks to control that movement.

The body, the engine, the payload, etc. are all sprung weight. The suspension, brakes, wheels, and tires are all unsprung weight. Unsprung weight is in motion, and needs to be controlled by your shocks. The more unsprung weight you have, the harder it is for the shocks to control that movement. It’s easy to catch a tennis ball. It takes much more effort to catch a bowling ball. You can run bigger shocks with more valving, but you are getting additional stress and strain on the vehicle. For those people who love their straight axles, it’s a small price to pay. When it comes to strength, and simplicity, the straight axle is hard to beat.

How It’s Made: Cast, Forged, and Flow Formed Wheels

A Look At Modern Wheel Manufacturing Methods

Let’s face it, when it comes time to select custom wheels for our vehicles, most of us only care about price, and style. While the right set of wheels can enhance the looks, and performance of your vehicle, having the wrong wheels can be downright dangerous. Anytime you increase the outside diameter of your wheels/tires, you put more demands on your brakes, and steering. It also affects your acceleration. A larger overall diameter can strain your driveline components to the point of failure. Manufacturing processes like flow form, forging, and casting is another thing to consider. With a little research, you can select a wheel that not only looks great, but actually enhances your vehicle.

Materials

Aftermarket wheels were originally made from magnesium, hence the name “Mag” wheels. Currently they are made from several materials including steel, aluminum, exotic alloys, carbon fiber; even plastic. We will focus on aluminum as most aftermarket wheels are made from aluminum alloy. During your selection process, do some research into the weight rating of the wheels you like, and how they are made. If you are racing on pavement, you probably want the lightest wheels possible. Light is easy, but strong and light takes more effort, and you will pay for the extra care and materials involved. You might be tempted by a big heavy wheel that is cheap. It may seem to be safe, but that’s not always true.

Standards

Cheap, heavy wheels made with inferior practices or to nonexistent standards, can be less expensive, but are no bargain. Properly constructed wheels will perform much better. The processes used, and the attention to detail may increase costs, but are crucial to a quality final product. Look for wheels that are tested to accepted benchmarks, and have been certified for quality. SAE (Society of Automotive Engineers), TÜV (German regulatory agency), ISO (International Standards Organization), and JWL (Japan Light Alloy Wheel Standard) all have standards for aftermarket wheels. You want the strength of your wheels confirmed in the lab, not on a public road or challenging trail.   

Techniques

Aluminum wheels can be made by several different techniques. The most prevalent are casting, forging, and flow forming. Casting and forging are unique. Flow forming uses a combination of both. Cast wheels have somewhat of a bad reputation for ultimate strength, but that reputation was earned by poor quality wheels from substandard suppliers. Cast wheels can be plenty strong as long as quality materials, and proper manufacturing techniques are followed.

In order to make a cast wheel, the aluminum alloy is brought up to a high enough temperature to melt it into a liquid. The liquid aluminum is then poured, injected, or drawn by a vacuum into a mold. One benefit of casting is that each part is an exact copy of the mold. Tight tolerances and uniformity is maintained. The cast part will have extra material (called flash) that still needs to be removed, but overall, the surface is smooth. The finished wheel can be polished or left as is. Due to the casting process, the aluminum material has a random grain structure. 

Forging

The forging process for aluminum wheels uses heat and pressure to form the part. Unlike the cast part, the surface can be irregular, and require a machining process to get it smooth. Hot forging is common on larger, thicker parts that require more movement of the material. Forging a complex part may require multiple operations with progressive dies to achieve the desired shape. Each additional step adds to the cost of manufacturing. The hot forging process begins with an aluminum slug that is heated until it becomes pliable. The slug is then placed into the forging press and it is either struck (mechanical press) or compressed (hydraulic press) into a formed die.

The part emerges looking like the shape of the die. These forging presses create incredible forces in order to move the material, and are huge in scale. Mechanical presses can be three stories tall with over half of the press underground. The building has to be built around the press. The big advantage of forged parts is the grain structure it produces. Since the material is formed, the grain structure is long, and continuous. A forged part is stronger, so the part can be made thinner, and therefore lighter.

“[Flow Forming] uses less material but is stronger, and lighter; all at a lower cost.”Sean Kleinschuster, Engineering Manager, Method Race Wheels

Flow Forming

Flow forming has benefits of both the casting, and forging processes. The wheel begins to take shape as a casting. The wheel face is cast, taking on the smooth finish that makes a casting precise, and cost effective. The casting is then heated and put on a turning die. While the part spins, hydraulically controlled tooling puts pressure on the part to draw the material out into the barrel shape. It allows the rim section to be thin for light weight, while having the strength of a forging.

“The public is more educated than ever about flow forming so they ask for it,” says Sean Kleinschuster, Engineering Manager for Method Race Wheels. “It uses less material but is stronger, and lighter; all at a lower cost. We use a proprietary heat treatment to our wheels that is higher than industry standards. We are getting material properties out of cast materials that are approaching that of a forging. Not only do we use computer generated finite element analysis, but we do extensive testing in race conditions. Our company started out in racing, and that’s where we validate some of our ideas. It’s good marketing, but we also use it for R&D. The technology we develop with rally racers and the top Trophy Truck racers goes into the same wheels you can buy off the shelf. We don’t have a separate race wheel department. We use the same materials and processes on every wheel we make.”

Because of the latest manufacturing technology, you can have a set of wheels that perform as great as they look. With flow forming, you can have race quality strength, and light weight, at an off the shelf price.

The Top 5 Underrated Off-Road Mods and Why You Need Them

We’ve all seen the mall-crawler trucks and SUV’s roaming the streets. Built with a credit card and a catalog, they look impressive to the average person, but to an enthusiast, they are quickly scoffed at. Huge tires on stock axles, and enough LED’s to light up a runway. They are bedazzled with spare gas cans, or a shiny new shovel that’s never been used. To be honest, many are nice looking, but most would fail miserably when put to the task. The ironic thing is that their owners have spent thousands of dollars on the look, without gaining performance.

You want rubber on the rocks and mud, not your fancy rims.

In the dirt where it counts, most factory stock vehicles are fairly capable, but they are designed as a compromise. Occupant comfort and fuel economy are major factors to designers. Since most vehicles spend a majority of time on the pavement, hard core off-road parts don’t take precedence. Thankfully, there are modifications you can make that will enhance your off-road capabilities without going overboard. We’ll share our top 5 off-road mod picks.

Number one has to be tires. Think about it. Your tires are the only contact you have with the terrain; they need to provide traction for acceleration, braking, and steering. The huge wheels with low-profile tires might look cool, but they don’t provide the benefits of a taller side wall. You want rubber on the rocks and mud, not your fancy rims. The number one factor determining the diameter of your wheels will be clearance around your brake components. On most trucks, a 16 or 17 inch wheel is plenty. Bigger, and wider tires will affect several factors. You will gain traction, stability, and ground clearance, but they will compromise your fuel mileage, turning radius, and your gearing. If you go too big, your truck will be a dog, and no fun to drive. You also need to have the clearance to fit that big rubber. That brings us to number two.

Whether you lift your truck or not is a major decision. If you are driving through swamps in Florida, or rock crawling out west, you might need some lift. In the mountains it may be the last thing you need to do. The swampers need as much lift as possible, while rock crawlers will want articulation as opposed to just height. If you regularly wheel in the mountains on tight, off-camber trails, a leveling kit or 2 inch lift is probably the most you want. Keep in mind, the taller you go, the more sacrifices you will be making. You will be punching a much bigger hole through the air, and you must be willing to forgo car washes, parking structures, drive thru’s or even your own garage.

This is where many people go off the rails. Your lighting has to be functional.

Number one, and number two will get you to more places off-road. Number three will get you back. 99 percent of the time factory trucks will not have any decent anchor points on the vehicle. The farther off the beaten path you travel, the greater the chance you have of getting stuck. Even if you have a winch, you will need anchor points on your truck. You do have a snatch strap, don’t you? Having a trailer hitch on the back is a great mod because it does double duty. You can tow, you can carry stuff with it, and it’s a solid anchor point. Up front you need to add something to pull on. A lot of trucks have hooks on the front, but many times they are for lashing the truck down during shipping, not for pulling out a stuck rig. They are known to fail. Anything you add will need to tie directly into the frame.

Number 4 is lighting. This is where many people go off the rails. Your lighting has to be functional. Many people emulate their Trophy Truck racing heroes and install incredibly bright (and expensive), off-road lighting. The technology available today is nothing short of amazing, but some of it is way overkill. Trophy Truck drivers need to illuminate the trail ahead at speeds in excess of 100 miles per hour. Will you be traveling that fast? You need to realize huge lights that send a beam out for 2 miles will limit when and where you can use them. No way can they be used on the street. Even off-road you will be shutting them off for the safety of others. Sometimes all you need are better bulbs in your factory head lights. Most of you will add wide angle lights, strategically placed on your vehicle. It’s good to have some bright lights shining ahead, but you also need light to the sides, and behind you. Backing up when your windows, and mirrors are covered in mud is not fun, especially when it’s completely dark behind you. You’ll want at least one flood light out back that lights up the ground, and the surroundings. The rear light can also be used when loading gear, or hitching up a trailer. Don’t forget the sides of your truck either.

When traveling down a trail at night, your headlights and/or driving lights are shining ahead. They don’t shed much light to the side of the truck. If you are searching for a side road to take, you will never see it. Known by many as “ditch lights” they can be mounted to the front bumper, on a light bar, or the windshield pillar. Ditch lights can also be used to light up your campsite, or when offering assistance on the trail. A set of rock lights will illuminate the undercarriage, and something portable is always useful. Whatever you decide to run as far as lighting goes, make sure you do a proper wiring job so they remain reliable. There are several products on the market that supply a separate dedicated power source for additional electronic components. They work well when adding lights.

There are countless off-road mods that will enhance your vehicle like extending your axle breather tubes to keep water out of your differentials, a more powerful alternator, additional fluid coolers, skid plates, or running an extra battery as a back-up, but the number 5 most underrated mod would have to be organization. You will need to carry spare parts, tools, food, drinks, clothing, bedding, the list is long. Having an organized truck with good storage makes every task easier. It also makes your truck safer. Loose gear in your truck can shift the weight enough to cause a tip over. It can break a window, or injure an occupant. Make sure you have heavy things tied down, and loose parts contained at all times.

These 5 off-road mods might not make you a hero at the mall, but will help you to have a safe enjoyable trip off-road.

What Are Beadlocks?

What are beadlocks, and what do they do? You might have heard the term beadlock used or seen the unique wheels on an offroad vehicle. Beadlock wheels are used in several types of racing, especially on dirt. Their look is distinctive due to the circle of bolt heads that run around the face of the outer rim. They look so good that many wheel manufacturers have copied the look without using the actual locking bead design. It gives any vehicle a purpose-built offroad appearance.

Real beadlock wheels provide an important function; they keep the tire bead locked to the rim. Typically the air pressure in your tires forces the tire bead into the lip on the wheel creating a seal that holds the air pressure in the tire. That design works well on the pavement where full air pressure is needed. When air pressure is too low on pavement, excessive heat is created, and tire failure is possible. Offroad vehicles sometimes run lower air pressure in the tires to allow a much larger contact patch on the ground; increasing traction. In deep sand and snow, the larger contact patch helps the tire to float on top instead of digging in which can get you stuck. Lower air pressures offroad will also give you a smoother ride, and allow the tire to flex over sharp rocks. A little give in the tire can prevent punctures from sharp rocks, especially in the sidewall. When rubber goes against rock, the rock usually wins. If you are going to run lower pressures, a beadlock wheel is necessary to prevent the tire from spinning on the wheel, or from losing air pressure all together. Once the tire bead becomes unseated, the tire can get damaged, and all traction is lost. If the tire comes apart, it can wrap around the suspension, rip off your brake line, or cause other damage to your shocks, steering, or body panels.

There are several types of beadlock wheels available. The most common style is the bolt-on outer ring. This style has a machined lip on the outside of the rim to locate the tire bead. Once the tire is slid onto the wheel, the outside tire bead rests on the machined lip. The locking ring then goes on top. Bolting the ring to the wheel clamps the tire bead to the rim and creates an air tight seal.

Military wheels use a different design. Instead of the ring clamping the bead to the wheel, they are more of a two-piece wheel with a cylinder that slides over the barrel of the rim. The tire goes on the wheel first. Then the cylinder is slid over the wheel inside the tire. When the outer rim half is bolted down, it clamps the inner cylinder between both inner and outer beads of the tire. The width of the inner cylinder needs to be matched to the thickness of the tire beads in order to work as desired.

Similar to the military style in concept, as it clamps both beads to the rim, a third design uses an inflatable bladder inside the tire. The bladder sits inside the tire on the barrel of the rim. Once inflated, it pushes out on both tire beads. This style can be used on most non-beadlock wheels. All that is needed is another valve stem added to the wheel in order to fill the bladder.

No mention of beadlocks is complete without discussing the elephant in the room. Every automotive forum online has a thread discussing whether or not beadlocks are street legal. Maybe the confusion comes from the old style wheels known as split rims. Split rims have a ring that sits between the tire bead, and a slight lip on the outside of the wheel. Air pressure seats the split ring against the lip on the rim. Split rims are notorious for coming apart when air pressure pumps up the tire. When they were used, the rim and tire were placed in a steel cage to contain the flying parts if the ring flew off. People were injured; even killed by split rims. That’s why they were phased out. The split rim is still used on heavy equipment tires, but you will not find them on anything but vintage vehicles. Most tire shops refuse to work on them. Tire shops don’t like beadlocks either, but one of the benefits of the beadlock design is that you can mount tires without any special equipment.

Beadlock rings are not illegal, but they can be dangerous if proper diligence is not used.

Generally, there are no laws that specifically outlaw beadlock wheels. At the same time, they do not satisfy the standards that have been adopted by many wheel manufacturers due to their multi-piece design. Beadlock rings are not illegal, but they can be dangerous if proper diligence is not used. Care needs to be taken during assembly. If the bolts are overtightened they can stretch, and fail. If they are not tight enough, the tire can move, and lose pressure. It’s important to tighten the bolts evenly, and to the correct torque value. Each manufacturer has their own standards depending on the bolts used, and the construction of the wheel. Some beadlock wheels have threaded steel inserts for the bolts. Other wheels have been heat treated to a condition that makes the aluminum able to hold a thread. Of course, there are steel beadlock wheels as well. If the tire bead is very thick, spacers may be needed between the rim and the beadlock ring. You don’t want a gap between the ring and the wheel as the tire bead can still flex. The bolts need to have the proper torque on them in order to work. If the bolts fail, the ring can fly off; a dangerous condition.

Once you get the hang of it though, it’s really simple. That’s another benefit of the beadlock design. If you get a flat tire, you can take the wheel apart, patch the tire, and then put it back together in the field. It will take some work; most beadlock wheels have 20 to 30 bolts. Another benefit of the ring style beadlock is the ring itself. It adds strength to the outer lip of the wheel. If you are grinding your wheels in the rocks all the time, you can replace the rings when they get gouged or worn down. When you look at the pros, and cons, beadlocks have a lot to offer on an offroad vehicle.

What Is A Turbocharger?

State of Speed Basics – The Manly Art of Automotive Knowledge

Ah, the noble turbocharger… Is there a more hallowed, or more misunderstood piece of high-performance hardware? It is the very definition of simplicity with only a single moving part, but it’s also incredibly complex in design and engineering that requires a mastery of aerodynamics, physics, materials science, and advanced manufacturing. Of course, nothing has catalyzed more keyboard warrior bench racing conflicts, with the possible exception of “NOS.” Today, we will separate fact from fiction, dispel some myths, and provide a solid education on the history, technical aspects, and practical use of turbocharging as it applies to high-performance engines. Strap in, because it might get a little bumpy.

Air Apparent

First, let’s define what a turbocharger does. When turbos were first being seriously developed during the period between the First and Second World War, they were referred to as “turbo-superchargers” which is a pretty good encapsulation of what they do. Turbos are part of the larger family of superchargers, which are defined as devices that provide air to an engine at a higher volume and pressure than the ambient atmosphere; but turbos are distinguished by the fact that they are powered by a turbine that is spun by exhaust gas, instead of a direct mechanical connection to the crankshaft. How much power an engine can deliver is based on how much fuel it can burn, and how much fuel it can burn is determined by how much air is available to mix with that fuel. You’ll often hear people talk about engines being “air pumps,” and to a certain extent, that analogy can help you understand the dynamics involved, even though it’s not perfect. The term “volumetric efficiency” sums up the breathing ability of a particular engine, and how much it can breathe directly affects how much fuel can be burned (and ultimately turned into power at the wheels.) An engine that operates at 100% volumetric efficiency takes in every bit of air that will physically fit in its displacement in every complete intake cycle. For instance, a 2-liter, 4-stroke engine at 100% VE will swallow exactly 2 liters of ambient air for each intake/compression/combustion/exhaust cycle across all its cylinders. In a naturally-aspirated engine, most of the time it will be operating at less than 100% VE thanks to the inherent inefficiency of the intake tract, valvetrain, and other restrictions. It’s possible to actually get that theoretical 2-liter engine to gulp down more than 2 liters per cycle in narrow operating ranges, thanks to clever camshaft lobe profiles and tuned intake and exhaust manifold design. But even the absolute best naturally aspirated engine will be lucky to get a few extra percentage points above 100% VE—there’s only so much that can be done with atmospheric pressure pushing air into the cylinders.

Under Pressure

This is the point where superchargers come in. Once you have a way to artificially push more air into the engine beyond what the ambient atmosphere can provide, the sky is (literally) the limit when it comes to volumetric efficiency. Superchargers (and turbo-superchargers) found their first high-performance application in aircraft engines; as altitude increases, the air available decreases, and at high altitude, naturally-aspirated engines can only produce a small fraction of the power they do at sea level.

Initial experiments centered around using supercharging to “normalize” available power and keep it constant as an airplane gained altitude, since engine output was acceptable at ground level, and the designs of the day weren’t able to cope with high boost and extreme dynamic compression. That would change in World War II as improved metallurgy, better engine designs, and high octane fuel all came together to allow more and more boost over a wider range of conditions without damaging the powerplant.

Once you have a way to artificially push more air into the engine beyond what the ambient atmosphere can provide, the sky is (literally) the limit when it comes to volumetric efficiency.

While many aircraft engines employed superchargers that were mechanically driven off of the crankshaft (often with multiple compressor stages and two-speed transmissions), other designs employed turbo-superchargers that were driven by the pressure of exhaust gas. The advantages of a turbo over a mechanical supercharger were numerous; they didn’t need to be directly coupled to the engine (in fact, the turbocharger in the Republic P-47 fighter was a full thirty feet behind the engine, tucked away aft of the pilot in the rear fuselage).

It was easy to control boost with a wastegate instead of a complex mechanical transmission (more on that in a moment), and best of all, instead of taking power away from the crankshaft to spin the compressor, a turbine provided that power for “free” by using the energy of the exhaust gas instead. 

While they made an appearance on cars in the inter-war years, in the post-war period saw both mechanical superchargers and turbo-superchargers gain in popularity with factory applications and hot rodders of all stripes—the appreciation of the power of boost had become mainstream, and there was no turning back.

How a Turbocharger Works

Part of the subtle beauty of the turbocharger is how simple it is, mechanically speaking. At its core, a turbo is simply a turbine wheel, a compressor wheel, and a shaft that connects the two. On the “hot” side of the turbo, an exhaust manifold sends spent gasses into the turbine housing and to the outside of the vanes of a turbine wheel, causing it to spin. The shaft transmits that rotation to the “cold” side of the turbo, where the compressor wheel ingests air in the center, then slings it out around the diameter of the wheel into the compressor housing. Automotive turbochargers almost exclusively use this sort of ‘centrifugal compressor’ to produce boost—rather than moving air like a desk fan, it works more like a playground merry-go-round, using the small but still significant mass of the air itself to create increased pressure as it is forced from the center of the wheel to the edge, where it is collected by the compressor housing and sent on to the engine.

The fact that a centrifugal compressor doesn’t really care whether it is spun by a turbine or by a mechanical drivetrain has caused many a noob to misidentify a ProCharger or Vortech supercharger as a “turbo,” since they also use a centrifugal compressor, paired with a belt or crankshaft-driven gearbox to provide power instead of a turbine.

Though they look the same at first glance, a quick peek behind the compressor housing will tell you if it’s being powered by the crank, or by exhaust gas. 

As was mentioned before, one of the advantages of a turbocharger is that it doesn’t place any parasitic drag on the crankshaft in order to produce boost. The energy required to spin the compressor comes entirely from the flow of exhaust gasses, effectively recovering power that would otherwise be lost.

…rather than moving air like a desk fan, it works more like a playground merry-go-round…

In order to control boost and keep it at the desired level, a device called a wastegate is used on the “hot” side of the system, ahead of the turbine wheel. Using a combination of spring pressure and a pneumatic actuator, the wastegate is a valve that can open to allow some of the exhaust flow to bypass the turbine to regulate how fast it spins the compressor on the “cold” side of the turbocharger. In factory turbo applications, the wastegate is often built into the turbine housing inlet as an “integral” design and uses a regulated pressure source connected through a computer-controlled solenoid valve to the intake manifold to open or close itself, based on how much boost the engine management system is requesting at that moment. Turbocharger systems for racing or aftermarket systems for street use often use a separate stand-alone wastegate to allow more precise control or to provide a greater bypass capacity than an integral wastegate.

On the “cold” side, you’ll often find a device that looks very similar to a wastegate, but that performs a very different function. Whether it’s called a “blow-off valve” or a “compressor relief valve,” it’s not there to regulate boost. This component provides another vital function—because air has mass and inertia, and so does the spinning compressor wheel, whenever there is a rapid change in throttle position there will be a sudden surge in pressure inside the intake tract. A good example is during an upshift when the throttle is momentarily closed between gears. Air that has been rushing toward the throttle body suddenly meets a restriction, and a pressure wave bounces off of it and is reflected back towards the turbo. This wave tries to slow the rotation of the compressor since it’s moving in the wrong direction, and if it’s strong enough, it can damage the shaft or even cause it to snap.

A compressor relief valve uses an actuator that compares the pressure in the intake tract between the turbo and the throttle body against the pressure inside the intake manifold on the far side of the throttle blade, and when there’s a significant difference (indicating that the throttle is shut), it opens to release the trapped pressure and prevent compressor surge. If the valve is open to the atmosphere, this is the source of the characteristic “Psssh” sound so many tuner cars produce, but most factory turbo setups will quietly recirculate this air via plumbing that sends the pressure around the turbo and back to the inlet.

Details, Details, Details…

At its most basic, a turbocharger setup just contains the key components listed above—a turbocharger unit itself that contains a turbine and compressor linked by a shaft, a wastegate to regulate boost and prevent the pressure on the intake side from exceeding desired levels, and perhaps a compressor relief valve to help keep the turbo spooled between gears and reduce surge loads. Like anything else related to high performance, though, things can get as complicated as you can possibly imagine.

Starting with the center section of the turbocharger, the shaft, which turns at tens of thousands of RPM at full-tilt, needs to be supported by a bearing to let it spin with as little friction as possible. Most turbochargers use a plain bearing, which works like the main and rod bearings on the crankshaft, using oil pressure to provide a cushion. A step up from there in sophistication are ball-bearing center sections, which don’t require the same high volume of oil to do the job as a plain bearing and offer less friction (and a little advantage in how quickly the turbo spools up). Ceramic ball-bearing center sections offer lighter rotating components and even less friction, with a commensurate increase in price. Finally, turbocharger center sections are often water-cooled via a connection to the engine’s coolant system in order to thwart heat from making its way from the “hot” to the “cold” side and to prevent extreme temperatures from turning the lubricating oil into carbon deposits inside the bearings. The size of the turbocharger has a big impact on engine performance; the larger in diameter the components are, the more airflow they can provide (and the more horsepower they can support), but this comes at the expense of slower response to changes in throttle position because of the increased inertia of the rotating assembly. Large single turbochargers are popular for drag racing where lag isn’t an issue, but for other forms of racing or street applications, twin turbo setups are popular, especially for V-type engines where each cylinder bank can have its own turbo. Some factory twin-turbo systems (I’m looking at you, MKIV Supra!) used two different sized sequential turbos, with the smaller unit providing boost at low load/RPM and transitioning to the larger one under full-boogie demand.

There’s Always More To Learn About Turbochargers

While we’ve looked at the basics of turbocharging, In the space we have available here, it’s impossible to cover all the important technical aspects of turbo system design and operation, and we’ve intentionally left out subjects like compressor housing A/R ratios, how to read a compressor map, the effect of intercooling, water injection, and cool-burning fuels like methanol, and dozens of others. Nevertheless, we’ve laid a foundation for further study, should you be interested in learning more. Remember, nobody is born knowing all this, and the only dumb question is the one that you never ask.

What’s a Hemi?

My very first car as a kid in England was a 1946 Riley RME. I thought it was cool because it had a chrome grille like a ’34 Ford and it had a race-developed, twin-cam HEMI—whatever that was. Back then, there was no internet to look things up but a trip to the library revealed that the word HEMI was an abbreviation for hemispherical combustion chambers—whatever that was.

Believe it or not, HEMI-heads are nothing new and their history can be traced back to the early 1900s when they could be found in a number of European cars including the 1904 Welch Tourist, the Belgian Pipe of 1905, the 1907 Italian Fiat Grand Prix car, the French Grand Prix Peugeot of 1912 and the Italian Grand Prix Alfa Romeo of 1914—race-bred alright. However, it was the Welch design that became the blueprint for the many successors that included numerous motorcycle engines.

Where the HEMI-head differs from other cylinder head designs such as the “flathead” Ford which is known as an “L” head design, is that their combustion chambers are hemispherical or half-bowl-shaped compared to most chambers that resemble a flattened, double egg. The chamber operates in a cross-flow configuration where the air-fuel mixture flows in one side; the more-or-less centrally located spark plug ignites the mixture and the exhaust gases exit on the opposite side from the inlet.

The use of a HEMI-head became prevalent in motorcycle engines because not only was it efficient, but it was not an overly complicated assembly in a single-cylinder application where the pushrods ran up the outside of the cylinder. Incidentally, a HEMI-head can be used with a pushrod, SOHC or DOHC valve train.

Believe it or not, HEMI-heads are nothing new and their history can be traced back to the early 1900s when they could be found in a number of European cars…

The concept even worked well in early air-cooled, radial airplane engines that are more-or-less a number of single cylinders arranged in a circle around a common crankshaft. In fact, by 1921 the U.S. Navy had announced it would only order aircraft fitted with air-cooled radials.

Obviously, World War II propelled engineering development, as it did with much technology, as speed and power became all-important. Chrysler worked with Continental on the development of a giant, 1,792 cubic-inch (ci) V-12 that would be used in the Patton tank. It produced 810 horsepower and 1,560 pounds-feet (lb-ft) of torque and enabled Chrysler’s engineers to gather some valuable information that they put to good use in their post-War automobiles.

In 1947, Zora Arkus-Duntov, the so-called “Father of the Corvette”, was commissioned by Ford Motor Company to improve the output of their aging flathead V8s. Zora, his brother Yuri and designer George Kudasch developed an overhead valve conversion (OHV) for the Ford V-8 that featured hemispherical combustion chambers. Tagged the “ARDUN”, which was a contraction of ARkus-DUNtov, their OHV heads looked great and increased the power, however, they were somewhat temperamental.

Only about 200 sets were made in the U.S. before Duntov moved to the U.K. to work with Sydney Allard where a few more sets were made for Allard’s J2 sports car. For many years, ARDUN heads were a much sought after hot rod accessory until the mid-90s when Don Orosco began to reproduce them. He made about 30 sets before the tooling was sold to Don Ferguson whose family continues to produce the heads albeit updated with some modern technology along with a compatible cast-aluminum block. Companies such as H&H Flatheads are known for building complete ARDUN engines.

While the Duntovs were working on the OHV Ford, Chrysler engineers John Platner, a graduate of the Chrysler Institute of Engineering, and William Drinkard, manager of the Engine Development department, got to work in 1948 downsizing that tank engine for use in an automobile.

The engine was tough and you could throw all kinds of power-enhancing devices from blowers to nitro and it thrived on it.

What they came up with was a 90-degree, 330 ci, cast-iron V8 engine with HEMI-heads. Code-named A-182, the “HEMI” was not quite ready for production and a lot of valve train development still needed to be done along with some ignition and crankshaft work.

Nevertheless, Chrysler debuted the HEMI V-8 for the 1951 model year as standard in the Imperial and New Yorker models and optional in the Saratoga. Initially, the “Fire Power” capacity was 331 ci due to an “oversquare” 3.81-inch bore and 3.63-inch stroke. With a 7:1 compression ratio (cr), it produced 180 hp and 312 lb-ft of torque but weighed a whopping 745 pounds—one head alone weighed almost 120 pounds and you’d better be wearing a belt when you lift one.

Chrysler’s DeSoto division came out with their 276-ci “Fire Dome” version in 1952 and Dodge followed suit with their 241 ci “Red Ram” in 1953. Although all three engines differed in detail, they shared the same basic architecture.

In 1955, Chrysler claimed a dual 4-barrel (bbl) Carter version the first production car to produce 300 hp. The displacement was increased in 1956 to 354 ci and the engine now produced as much as 355 hp and became the first American engine to produce 1 hp per cubic inch.

Two years later, the infamous 392 version was introduced and it was almost square having a 4-inch bore and a 3.906-inch stroke. It had a taller ‘raised deck’ compared to previous engines; however, the heads were cast with wider ports so that earlier manifolds could be used with the new heads on the new block. The following year, a single carb version with 9.25:1 cr was rated at 345 hp while a dual-carb version offered 375 hp.

The 392 is significant because it became the drag racer’s engine of choice, especially in the fuel ranks: Top Fuel, Funny Car, and Fuel Altered. The engine was tough and you could throw all kinds of power-enhancing devices from blowers to nitro and it thrived on it.

By 1958, the 392 was producing 380 hp but had reached the end of its production life. It wasn’t until 1964 that Chrysler re-introduced the engine and officially called it a HEMI. Nicknamed the “elephant engine,” because of its size and weight, the new Gen II HEMI displaced 426 ci. Not initially available to the public, it was used in NASCAR in ’64 but not in ’65 because it was not available in a production car and therefore could not be raced.

Not to be outdone, Ford also introduced a 427-ci HEMI in 1964. Nicknamed the “Cammer” because it had a single overhead cam (SOHC), engineers had worked hard to design a symmetrical combustion chamber with the plug located for maximum efficiency only to discover that the plug didn’t care where it was. The plugs were then located near the top of the cylinder for easy access. NASCAR wasn’t at all happy about these “special” racing engines, however, the “SOHC” motor (pronounced “sock”) remains a “halo” engine for Ford.

Chrysler fixed their NASCAR problem in 1966 by introducing the “street” HEMI with lower compression, a milder cam, cast instead of tube headers and two 4 bbl Carter AFB carbs. The Gen II HEMI was produced until 1971 and was rated at 425 hp at 5,000 rpm and 490 lb-ft of torque at 4,000 rpm.

Of course, this is only the American version of HEMI history. Across the pond, in the homeland of the HEMI, the Europeans never left the concept alone.

Incidentally, the 426 HEMI is a HEMI in name only. Rather than build the new 426 from the old architecture of the 392, Chrysler engineers chose to use the existing 440 Wedge-head big-block. That said, the 426 evidences many improvements over the Wedge and indeed the 392 and became the modern drag racer’s engine of choice and was known colloquially as the “late model” compared to the 392 “early model.”

As the factory HEMIs came to the end of their respective lives Ed Donovan of Donovan Engines introduced a cast-aluminum 417 ci aftermarket version in 1971 that was based on the 392. That was followed in 1974 by Keith Black’s 426 HEMI based on the factory 426. Versions up to 573 ci are now available as are heads and numerous other parts milled from billet aluminum from numerous aftermarket manufacturers such as Hot Hemi Heads.

In fact, we use a billet 417 ci Donovan block with billet heads from Hot Hemi Heads in Ron Hope’s Rat Trap AA/Fuel Altered that we race. With a billet BDS supercharger and 90-percent nitro, it produces some 3,000 hp. However, in current Top Fuel/Funny car racing they use architecturally similar 500 ci blocks milled from forged billet aluminum.

These proprietary blocks are produced in-house by Don Schumacher Racing and John Force Racing but similar blocks that can withstand in excess of 10,000 hp are available from companies such as Brad Anderson and Alan Johnson Performance—all based on that Chrysler HEMI.

Of course, this is only the American version of HEMI history. Across the pond, in the homeland of the HEMI, the Europeans never left the concept alone. For example, Daimler, using Triumph motorcycle architecture, developed two aluminum-headed HEMI engines of 2.5 and 4.5-liters.

Other British brands such as Aston Martin and Jaguar both employed hemispherical combustion chambers in the DOHC V-8s and straight 6s respectively. However, no doubt the most well-known use of their HEMI-head was by Porsche in many of their engines—particularly the flat-six boxer engines of the 1963-’99 911s.

Choosing the Right Tire

Let’s face it, the weather out on the West Coast is awesome. The conditions are more or less predictable, the climate is almost always in the ’70s and sunny, and it’s generally easy to prepare for changes in conditions if, say, you travel up to Tahoe for some skiing.

But for those of us that live virtually anywhere else, Mother Nature chooses to be comparatively more cruel with her distribution of weather conditions. Those of us residing in the Midwest and on the East Coast, as surely you already know, experience seasons; actual changes in temperature and conditions from winter to summer and vice-versa.

Whether you’re an automotive novice or expert, you know that tires are your vehicle’s direct line of contact to the road. Aside from monitoring your vehicle’s tire pressure, treadwear, etc., it’s essential that you also choose the right tire for the season and conditions you’re driving in. The circumferential grooves, tread blocks, lateral grooves, and even whether or not a tire is siped can have an impact on how a vehicle handles and brakes in both the wet and the dry.

Every kind of tire from all-season to all-terrain has specific conditions in which they excel, and this article will help you decide on what kind of tire to use when.

All-Seasons, Not All-Conditions

These are the most common kind of tire found on standard passenger vehicles and SUVs. As their category name suggests, all-seasons can be used in virtually any weather condition. Most vehicles that are equipped with these kinds of tires are used for commuting, not racing, have tread patterns with wider circumferential grooves (for removing water), more basic lateral grooves and tread blocks, have lower speed ratings (S- or T-speed), and longer-lasting rubber compounds.

For vehicles that are more performance-oriented, a performance or ultra-high performance tire isn’t necessarily more appropriate but will compliment your vehicle’s handling and braking abilities in dry conditions, while maintaining wider circumferential grooves to disperse water. These tires have a more intricate, aggressive tread pattern from the outboard to inboard shoulders, higher speed rating (H- or V-speed), and a softer compound, which tends to wear quicker than regular all-seasons.

The Milestar MS932 Sport and MS932 XP+ tires are great examples of this. Both are high-performance tires that feature optimized tread patterns along with wide circumferential ribs and grooves for improved grip and water dispersion. Compared to the MS70, which has both vertical and variable siping for inclement weather, the Sport features lateral siping while the XP+ features 3D, zig-zag siping, which are geared more for a performance grip. The XP+ has the addition of wider shoulder tread blocks for better handling and cornering.

When it comes to colder and wetter conditions though, the performance-oriented all-season tires aren’t as great. Their rubber compounds aren’t made for colder temperatures and the more aggressive tread patterns mentioned limit the vehicle’s ability to not only grip the road but also disperse precipitation when there is water or snow on the road.

…tires are your vehicle’s direct line of contact to the road.

In extreme cases, this could result in hydroplaning, which is essentially when water cannot effectively pass through a tire’s circumferential grooves causing the tire to ultimately lose contact with the road.

Condition Specific Tires: Winter And All-Terrain 

When temperatures drop below 40 degrees or the terrain becomes rough, rocky, or muddy, an all-season tire isn’t going to cut it. Lower temperatures demand tires with specialized, temperature-specific rubber compounds for better grip, while inclement weather conditions and rougher terrain demand specialized tread patterns for better grip. That’s why winter and all-terrain tires exist.

A tire which has met the required performance criteria in snow testing (like the situations mentioned above) will be branded with a three-peak mountain snowflake (3PMS or 3PMSF) symbol on its sidewall. Traditionally, this designation was used only on winter-specific tires, but as of late, more all-seasons have been receiving the certification as well.

Both winter and all-terrain tires have wider, deeper circumferential grooves for maximum water dispersion along with siping. This is where siping, tiny straight or zig-zagged grooves within the tread blocks, really comes in handy. As the sipes come into contact with a surface, they aid the tread blocks with better grip.

In more extreme cases, adding studs to or wrapping them in chains might be necessary. These studs are small pieces of metal that can literally be installed into the tire’s tread and help the tire dig into ice and snow.

When temperatures drop below 40 degrees or the terrain becomes rough, rocky, or muddy, an all-season tire isn’t going to cut it.

Milestar’s Patagonia A/T W is an excellent example of a studdable tire, which has small indents throughout the tread for stud installation and is supplemented with segmented wishbone tread blocks and silica compound for better overall grip.

Similarly, wrapping a tire in specialized tire chains also helps a tire dig to ice and snow, but can be harmful to the pavement when ice or snow isn’t present. Consulting both your car’s user manual as well as with a tire shop is highly recommended if you choose to go for either of these options.

When it comes to all-terrain tires, their inboard and outboard shoulders are typically comprised of lugs—extra large “chunks” of tread—in addition to most standard tire components. The Milestar Patagonia M/T is a great visual example of this. It features high void, lugged tread for maximum traction on rough terrain.

With All That Being Said…

No matter which brand of tire you decide to purchase for your vehicle, it’s essential to choose the right one for it as it could potentially have a huge financial impact. Driving on a winter tire year-round, for example, will yield much quicker tread wear along with poor overall gas mileage. On the flip side, driving on an ultra-high performance tire in inclement weather puts you at a much higher risk of hydroplaning and even crashing.

“The choice is yours, and yours alone. Good luck!”

On a Dime: Brake Tech – Theory and Warping

Theory and Warping

Your brakes are possibly one of the most important parts of your car or truck. However, it’s probably one of the least well known after the shocks. Let’s talk about the basic theory of your brakes and discuss what “warping” really is.

You need to stop or slow down for that next corner but letting off the gas won’t slow you enough in many cases. In those cases, you need to get on the binders. When you hit your brake pedal, fluid is sent from the brake master cylinder to your calipers and/or drum wheel cylinder to move a set of pads or shoes against a rotating surface.

Those pads and shoes are fitted with a friction material that clamps down on that surface to take kinetic energy, in our case that is wheel rotation. That then turns that kinetic energy into thermal energy from the friction between the friction material and the rotor or drum surface. This friction causes the wheel to slow until it is stopped.

Well, they don’t warp like a wet piece of board does.

While your tire’s traction will determine how effective your braking is, the coefficient of friction of the brake liner will determine how much bite the pads or shoes will have on the rotors or drums. That thermal energy is then radiated away by airflow over the surface area of the rotor or drum.

Discs or rotors of the disc brake system do an equal amount of the hot work of the brake system, but they also do more than just transfer heat. Their face designs help the pads do their job, but what about the issue of rotors “warping?” Well, they don’t warp like a wet piece of board does. What’s happening is that the pads are leaving some of their friction material on the rotor surface under harsh braking.

Notice that “warping” is in quotation marks here. Your rotors do not warp in the sense that wood warps when it gets wet. Instead, what’s happening is that the brake friction material is transferring unequally to the rotor face. This can happen because of unequal temperatures on the surface of the rotor, a hotter spot on the rotor will transfer more friction material onto the rotor surface than the colder spot.

…what’s happening is that the brake friction material is transferring unequally to the rotor face.

This creates an uneven surface that transfers into the brake calipers and creates the judder and vibrations associated with “brake warping.” When a technician resurfaces the rotor, they are removing that access material along with the rotor surface to create an even face again.

That’s not to say a brake rotor can’t warp, but if it does there’s a whole host of other problems going on and usually, the rotor will crack and break before that warping happens.

Now that we’ve covered that, how about those rotors or brake pads?

Bias Ply vs. Radial Ply Tires: What Is the Difference?

When it comes to your standard driving tires, bias ply hasn’t been a term used in decades to describe the latest and greatest tires coming out on high-performance cars. In the racing, trailer, and even motorcycle worlds we still see bias ply but, even then, it’s quickly being displaced by radial tires. So, what is a bias ply and why has it been replaced by radial ply tires?

What’s being referenced when you talk about bias ply and radial ply are how the cords that make up the carcass of the tire are run from bead to bead. You’ll never see it until you wear the tread beyond its rubber layer. The term “bias” and “radial” are describing how the patterns of the ply are done.

A bias ply tire has its plies in a crisscross pattern as they overlap each other. So, one ply will lay in one diagonal (between 30- and 40-degrees from the direction of travel) while the other will lay in the opposite direction and would make an “X” if you were able to see through them. You can have multiple plies in a bias ply tire, too, usually in 4, 6, 8, or even 10 plies.

Most will be 4 plies, though. Bias ply tires also use far more rubber to create both the sidewall and tread as well as being supported by the plies. This was how tires were done from the 1930s all the way into the 1970s, with the last few cars coming with a bias ply in or around 1974.

A bias ply tire is far more flexible, so they can make for great off-road tires and drag radials where sidewall flex is beneficial. They also exhibit better traction at low speeds and in straight-line travel.

[Bias ply] treads wear faster and exhibit more rolling resistance, so you go through more money as you use up the tires and your gas far more often.

Because so much rubber is used, they are far more resistant to cuts and punctures. However, because they use so much rubber and are more flexible, they lose traction in cornering because they tend to roll-over on to the sidewall.

The treads wear faster and exhibit more rolling resistance, so you go through more money as you use up the tires and your gas far more often. This also means you’ll get flat spots if you allow a bias ply tire to sit on the vehicle’s weight for too long. You’ll also feel like your wandering due to cracks, ruts, and bad driving surfaces as these tires tend to follow those deformations.

While the tread isn’t directional, the way you rotate bias ply tires for maintenance is specific to them. You’ll take a left rear tire and move it to the left front, left front to the right rear, right rear to the right front, and right front to the left rear. Well, unless you have five tires (where you can use the spare as a normal driving tire) and then the left front becomes the spare and the spare moves to the right rear.

A radial tire, however, has its plies in a 90-degree pattern from the direction of travel from bead to bead (or radially from the center of the tire and where they get their name from). They have been around longer than most people realize, with tire patents dating back to 1915 by Arthur Savage in San Diego, California (the patents expired in 1949).

In France, Michelin designed, developed, patented, and commercialized a radial design by their researcher, Marius Mignol, in 1946 and Michelin X radial tires were installed as a factory standard tire for the 1948 Citroen 2CV.

…[Radial ply tires] have been around longer than most people realize…

The first factory standard radial tire for the US is credited to the 1970 Lincoln Continental Mark III after the August 1968 issue of “Consumer Reports” showed that they had better tread life, better steering characteristics, and less rolling resistance.

What makes the radial superior to bias ply tires (outside of high-load capacity) is that those radial cords allow better flex. It makes a tire act more like a spring and improve riding comfort even as load capacity rating increases. This also increased tire life as the flexing required was easier than bias ply, which would resist and begin to overheat the tire. Because of its radial pattern and using less rubber, you’re able to run a much wider and flatter tire footprint.

These tires will also have a rigid set of belts to reinforce the tread, usually made of steel, Kevlar, polyester, Twaron, or sometimes even a combination of them. That means that your sidewall and tread function as two independent part of the tire instead of one like a bias ply.

These belts can also be added between plies to meet specific design goals like reinforcing the sidewall for puncture resistance, increasing load capacity, and many other objectives.

Because of that and the expansion of rubber compounds using silica, we’re starting to see more and more applications that use radial tires over bias ply. In racing, many tires are now radial over bias because of the advantages of feel and character of the radial.

Much like the carburetor, the bias ply won’t go away but it will be only around for the niche.

Even drag radials are offering more straight-line grip and sidewall flex needed for powerful launches on the strip with the added benefit of not needing inner tubes.

For off-road, radial tires offer better flex and more grip on the rocks and sand. Trailer tires have even begun to make the switch to radial, even in higher load capacities typically reserved for bias plies. If you’re trying to look period correct, there are even radial tires for you.

The short story is that the areas where bias ply dominated are no longer solely for them. Radials have become an acceptable replacement in those areas. As ply and rubber technology continues to improve, the need for any type of bias ply will be left for those who are just in it for numbers-matching correct restoration. Much like the carburetor, the bias ply won’t go away but it will be only around for the niche.

Is There an Ultra High Performance Tire Right for You?

You build your car and have made it look like something straight off the race track. However, you don’t plan on driving it on the track all that often. Should you really have a set of Ultra-High Performance tires (or commonly known as UHP tires) on something you don’t track?

Someone who builds a cool looking car that’s low and functional doesn’t always end up on the race tracks across the world. There’s nothing wrong with that and people have been doing that since the early days of hot rodding. Even if they do track their cars, many drivers assume they need UHP Summer or “R-compound” tires for their car when, in reality, they don’t need them for daily driving. They quickly realize they are starting to waste a lot of money on those rubber donuts.

This type of UHP tire is typically designed to be used in environments that are warm and dry enough that they provide the right amount of traction to drive fast. The tread itself is very thin, usually no more than 5/32-inch deep with few sipes and grooves.

They quickly realize they are starting to waste a lot of money on those rubber donuts.

This means the ultra-high performance tread pattern is focused on providing maximum grip to a “clean” driving surface and their tread blocks will have very few voids and channels for water evacuation. Their rubber compound will also be softer to provide more mechanical grip at the limit.

This also equates to a tire that can take some time to learn to drive on the limit with. Many times, they don’t make enough noise or even breakaway slowly. When you go over their limits, it characteristically happens fast and without any audible warnings like you get from your typical street tire. It’s why many track day teachers will tell you not to drive on a UHP tire on your first few events until you get used to your car and how to drive by feel rather than sound.

It’s these characteristics that also make a UHP Summer tire wear faster than a standard street tire and doesn’t work in all seasons. If you drive your car where it rains often or you must drive through even light snow, these tires won’t work. They just aren’t designed to evacuate precipitation that hits the ground and you’ll begin to hydroplane.

UHP Summer and even Winter tires aren’t meant for daily, yearlong driving…

While having a softer compound is great for cold climates—where normal street rubber would become harder and not grip—that compound will also wear much, much faster. Ultra-High Performance Summer and even Winter tires aren’t meant for daily, yearlong driving because they wear much faster in warmer weather.

However, that doesn’t mean there isn’t a UHP tire you can’t take advantage of. You should look at the UHP All-Season tire for your daily driving needs. These tires have the tread pattern to allow for water and even snow evacuation so you have grip in the wet. The tread is usually between 8/32- and 11/32-inch deep but their tread siping is also designed to support their neighboring tread blocks using interlocking sipes. This means, as you corner in a high-G load, the tread blocks support each other and prevent them from bending too much during cornering, decreasing heat that leads to tire tread chunking and degradation.

They also have a specific tread compound that works in both warm and cold environments as they contain more silica in the compound. The black color your tires have comes from carbon black. This carbon black also helps determine the softness of the rubber compound, so the more carbon black, the softer the compound is.

…UHP All-Season tires really can let you have your cake and eat it, too.

Tire manufacturers have begun to use silica (also known as silicon dioxide), a type of compound that many try to describe as sand. Silica is only a part of sand, however, as this compound is also found in quartz and even living organisms.

What makes silica amazing, and why it’s being used in UHP tires more often, is that it provides a lower rolling resistance while also improving the grip of rubber tires and results in a more elastic and flexible compound at lower temperatures versus similar tires with more carbon black. According to Rubber World, “The use of silica can result in a reduction in rolling resistance of 20% and can also improve wet skid performance by as much as 15%, substantially improving braking distances at the same time.”

So, UHP All-Season tires really can let you have your cake and eat it, too. However, if you are participating in a track day and have some experience under your belt, you should be using a set of UHP Summer tires then. If you’re just trying to look the part, you can stick with the UHP All-Seasons all year long. That way, you get the benefits of more grip without the headaches of spending money on constantly replacing worn tires and worrying about hydroplaning in the wet.

Going Big: A General Guide to 40-Inch Off-Road Tires

Going off-roading means you need 40-inch tires, right? Well, it depends. There are some things you need to take into consideration before going oversized.

First, we must confess that this is a bit of a generalization. What we’ll be discussing here might not be exactly what your truck or SUV needs to make that jump to a 40-inch tire. For example, your rig might come with axles strong enough to turn a 40-inch tires without breaking the splines or itself in half. You might be able to remove your fenders on your Jeep but the guy in the F150 can’t.

If you’re just a mall crawler, you might be fine with mostly stock stuff, but if you do go off-road, you’ll need upgrades. So, this will be a guide of things to take into consideration before plunking down cash on those big tires. We won’t touch on anything specific to any single vehicle.

Let’s start with the thing everyone points out as the first thing to change or at least modify: your axles. First, why? Why do you need to consider your axle when changing to larger diameter tires? Much of it has to do with the diameter and additional weight of the tires. Yes, you need to re-gear (and recalibrate your speedometer) to overcome the increased overall gear ratio. A 33-inch tire will have a rollout of 103.7-inches and will rotate 630 times per mile.

A 40-inch tire, on the other hand, will have a rollout of 125.7-inches and will rotate 517 times per mile and means you are going further on each rotation. By changing to a taller tire, you’ve essentially increased your overall gear ratio and will be showing a slower speed than what you’re actually doing. So, if you were doing 65-MPH with a 33×12.50, you’ll be doing nearly 80-MPH with a 40×13.50 while still showing 65-MPH.

…if you’re going with big tires, most likely plan on going with bigger axles at the same time.

This means you would not only have to recalibrate your speedometer but also need to re-gear to keep the engine RPMs close to the same for the corrected speed. Fortunately, there are many online calculators to help you determine what gear you need for the tire size increase as well as handheld tuners that allow you to recalibrate your speedometer for your tire size and gearing.

That won’t be the only problems with your axles, though. Because of the increased weight, you’ve also increased the rotational mass and resistance to rotation. This means you’ll need more torque and you’ll do that by adding power or decreasing your gear ratio or both. This increases stress on the axles and usually leads to failure at the splines and axle shafts on straight axles and, additionally, failure of U-joints or constant velocity joints on independent axles. So, if you’re going with big 40-inch tires, most likely plan on going with bigger axles at the same time.

You’ll probably want to invest in new driveshafts, as those will be the next weakest links when it comes to transferring torque to your axles. Most truck and SUV transmissions and transfer cases can operate fine with big tires, but you’ll want to inspect them more often or consider a swap out for heavier-duty versions from the aftermarket. You won’t necessarily need an Atlas or even an NP205, but definitely look for upgrades for your chain-driven New Process transfer case that will allow it to handle more torque. However, if you have a regular NP241, get something better or at least an NP241HD.

You’ll need a lift, even if you already have a 2- or even 3-inch lift you’ll need to go a bit higher to clear the tires. This is where an IFS suspension starts to lose its advantages as you raise the truck higher, it will continue to ruin the steering and feel of the truck or SUV. You’ll also wear parts out much quicker because of the stresses and the increased load of the lift as well as the tires.

…it’s probably best for only hardcore off-road rigs and showboaters.

You’re looking at a custom suspension regardless if you stay with your IFS or swap the front to a solid axle. For the rear with leaf springs, you’ll be able to find re-arched springs for a decent lift without needing to resort to a huge block for sprung-over axles (where leaf sits on top of the axle). For sprung-under, you’ll have to convert it to sprung-over or you’ll have arches so large it will be pointless.

If you don’t lift, the body will need extensive modification for a 40-inch tire to work. If you don’t want to cut sheet metal, your only other option will be to replace it with fiberglass parts made for prerunners and desert trucks. If you cut metal, most states will require you to have something to cover the tires and have clearance lights on fender extensions to remain legal. Easy to do on a Jeep, not so easy to accomplish on anything with a regular body.

You’ll also have to make sure the wheels you use to give you the right backspacing (offset) to clear those very wide tires. The rear can typically be more aggressive than the front and can get away with higher backspacing (lower offset). The fronts, however, need to be spaced so that you can turn properly and not rub the frame or suspension components. Again, in many states, there are also legal issues with tires rubbing the body and chassis.

Running 40-inch tires isn’t easy, in fact, it’s probably best for only hardcore off-road rigs and showboaters. It’s not impossible to run that big of a tire, but there are many, many things you need to consider before doing it. This is just a short list as there are explicit things you need to do to specific vehicles to run tires this big. The best piece of advice we can give you is to research. Look for who’s done it with a vehicle like yours and see the trials and tribulations they had to go through to make it work. Then, decide if you’re willing to do the same.

If not, there’s nothing wrong with running 35s on your truck, SUV or Jeep and they are plenty capable. Just ask the guys who race in the Ultra4 Every Man Challenge.

38 Inch Special:
A Guide to 38 Inch Tires

Go into any current forum or social media group for Jeeps and 4x4s and you will find the most frequently asked question is “How big of a tire can I fit on my *insert 4×4 here*?” The question is posed so frequently that the query is “stickied” to the top of the forum page with countless replies. “You can fit 35 inch tires if you have…” “37 inch tireswork, but only if you’ve done…” “You need tons in order to run 40 inch tires…” (“Tons” is shorthand for 1-ton axles sourced from a pickup). They’ve all been asked.

These seemingly universal 4×4 questions have been answered in their entirety, which we won’t get into here. The Jeep community has seen the 37×12.50R17 become the ubiquitous size on any new Jeep. Go back just over a decade and 37s were the extreme size tire to have and only a handful of brands to choose from. 33s and 35s were BIG, but 37s meant you were serious! So how did this desire for ever-larger tires come to be so common and why is there such a jump in size going from 37 inch tires to 40 inch tires with no choice in between?

In today’s tire world, nearly every tire manufacturer has an All-Terrain (A/T) and a Mud-Terrain (M/T) in a 33, 35, or 37 inch tire that fits on a 17 inch rim. These sizes have become a standard upgrade for several reasons. First is 4×4 vehicles are bigger than ever before with auto manufacturers adding extra space, seats, and cargo capacity. Second, with the added space and creature comforts comes the weight.

33s and 35s were BIG, but 37s meant you were serious!

Everything gets bigger from the drivetrain, axles, brakes, steering to handle the extra weight and still be a capable vehicle. This transition to more capacity and capability was lead by growing popularity in outdoor activities amongst families. With the vehicles and their components getting bigger and adding capability, enthusiasts took to modifying them with greater earnest and in greater numbers. One of the easiest ways to add capability is by gaining clearance through a larger tire size.

It can be argued that this rapid expansion in tire sizes was brought about by the advent of a single vehicle: the 2007 Jeep Wrangler Unlimited (JK). It dropped the iconic Inline 6-Cylinder for a V-6 that was better suited to a minivan than a 4×4. The improved approach and departure angles showed enthusiasts that Jeep engineers were focused on making a capable vehicle.

But the one change that was seen as heresy initially and is now beloved: 4 full doors. Jeep aficionados scorned the longer Wrangler, thinking it more of a minivan than a true Jeep. But over time, the extra wheelbase lent itself to improved off-road capability, with the right modifications.

Chief among them: Larger tires. Tires are the only thing that connects the vehicle to the ground. They are the easiest and quickest way to gain ground clearance, improve approach and departure angles, and provide that oh-so-desirable “tough” aesthetic that many enthusiasts are after. But there is a canyon in terms of budgets between running a 40 inch tire and the ubiquitous 37 inch tire.

But the one change that was seen as heresy initially and is now beloved: 4 full doors.

40s are an average of 40-60% more expensive than their 37 inch tire counterparts, and a lot of expensive changes have to be made to the vehicle in order to reliably run a 40 INCH tire as well. So what does an owner do when they want more than their 37s, but can’t afford or justify the required upgrades for 40s? Enter the Milestar Patagonia 38 inch.

While the 38×13.50R17 is only one inch taller than its smaller sibling—the 37 inch, it pays off in ways that become greater than one would initially think. It poses less strain on the hard parts that turn and drive the tires when compared to 40 inch tires. The 38 inch tire size clears factory brackets and bumpers and keeps any sort of body modification to a minimum.

Wheel offset, suspension bump stops, steering, and fenders all can stay the same if the vehicle has been properly kitted for 37’s. Where 37’s provide a better “stance”, the 38 inch tire make the vehicle look like it has 40s. All of this is gained with a reasonable bump in price on just the tires. Not only is the 38 inch Patagonia M/T taller, but it’s a bit wider at 13.50 inch giving the wheeler that much more of a footprint.

The tires’ C-Load Range is also a nod to the recreational wheelers as it is commonly thought that having some sidewall give, while still being 3-ply, will allow the tire to “grab traction” or “bite” when aired down. This is further supported when one takes into consideration that tire manufacturers often modify the construction material of the plys depending upon the load the tire is expected to bear and how much air pressure it is rated for.

…the added capability of a 40-inch tire, without the 40-inch wallet.

Strength is upheld with the Patagonia, while being a more focused 4×4 product. At 82 pounds, the 38 inch Patagonia M/T’s optimized construction is shown as it is the same lighter weight as many of it’s 37 inch competitors. This is important because added unsprung weight negatively affects suspension performance and ride quality.

In addition, extra weight also brings down fuel economy and increases wear and tear on the drivetrain and steering components. The 38 inch Patagonia M/T is constructed to balance strength, size, and weight; all major factors when enthusiasts start their 4×4 project.

The 38 inch Milestar Patagonia M/T is the choice when one wants the added capability of a 40-inch tire, without the 40-inch wallet. It is tailor-made for the recreation wheeler with its strong, yet pliable sidewall, all-important 17″ wheel construction, and true 38 inch tire sizing. Your next question is simply where will you buy your set?

Driving on Air: Why You Should Drive on Air Suspension

For anyone who is already into modifying cars, you already know that the possibilities for changing the look and feel of it are literally endless. Everything from replacing the factory wheels, headlights, and taillights to adding aerodynamic pieces like front lips and wings all play a part in a vehicle’s transformation. Lowering a vehicle is one of the best ways to change how your car looks and feels. Not only are you lowering the center of gravity, allowing for better handling (in most cases), it also makes for a more aggressive appearance, since the car itself sits closer to the pavement. This is where lowering springs, coilovers, and air ride suspension comes in.

In this day and age, there are a number of ways to successfully lower essentially any vehicle on the planet. Like @_.b7land.yacht._ (Frank Reichard), many choose to use air suspension as their lowering method of choice, which utilizes compressed air to inflate and deflate individual strut bags. With air ride, a driver can lower his or her car to “undriveable” heights and, in some cases, higher than stock all with just the touch of a button.

Air suspension isn’t always an aftermarket modification though. Many automotive manufacturers like Mercedes and Land Rover incorporate air suspension into their vehicles right from the factory!

“BAGGING” A CAR

As the owner of a bagged vehicle, I can tell you first-hand about the pros and cons of the suspension. I primarily had it installed on my 2005 Subaru Baja Turbo to competitively display at car shows. Aside from the fact that virtually no one was “bagging” this kind of car, I wanted to get the Baja as low as humanly possible without having to semi-permanently leave it at that height. My previous car was a built “Bugeye,” which I had coilovers and, while I could theoretically lower it as much as I wanted, my height choice often resulted in punishing results to the car. For instance, I once had my Bugeye so low to the point where I naively (and stupidly) rubbed the passenger front tire through the car’s main wiring harness. But I digress.

My good friends Rich, Don, and Hans of Tuning Works were the ones responsible for installing air ride on both my and Frank’s vehicles (a 2018 Volkswagen Passat GT), among other customers. Air ride installations make up a substantial portion of their business, and they’ve done hundreds of installations for customers to the point where they can complete one from start to finish in as little as four days.

The guys will tell you firsthand that the actual installation of the strut bags, air lines, compressor(s), tank(s), and wiring is the easy part. It’s the seamlessness of how all of these components are installed along with the creativity in its display that is the real challenge. But with that being said, the guys at Tuning Works pride themselves on consistently completing seamless and creative installations for all their customers.

When it comes to the creativity side of things, the sky is really the limit. So when Frank asked for his trunk display to be Supreme-themed, they accepted the challenge without the slightest bit of hesitation. He provided them with two Supreme Tool Boxes, which were used as housings for the air compressors and water traps – devices used to keep water out of the air tank and lines. Tuning Works had the air tank powder coated Supreme Red and cut a matching Supreme logo sticker for the tank on their vinyl plotter.

In many cases, the challenge of creating a good trunk display lies installing the necessary components while maintaining as much of the vehicle’s trunk space as possible. A good portion of Tuning Work’s customers want to keep some storage space in their trunks and have easy access to their spare tire (assuming they have one).

To retain the functionality of Frank’s trunk, Don fabricated a two-piece floor. The piece sitting closer to the back seats neatly holds the tool boxes, while the piece closer to the trunk lid can be removed so Frank can get to his spare tire. The brain of the air suspension system, Airlift’s 3P Digital Air Management, was conveniently installed on a “plate cover” of sorts, which sits on top of the spare. So if Frank needs to take his spare tire out, his wiring, lines, and compressors won’t be disrupted. To finish things off, both the floor and cover were wrapped in matching trunk carpeting for that OEM look.

None of the aforementioned components can work effectively to inflate or deflate the bags without the air tank though. So to save even more space in the trunk, the team fabricated and installed custom brackets for the tank to sit on that sit nicely behind the back seats. The brackets make it look like it’s floating, which is super cool.

Frank’s Passat GT is (unofficially) the first model “GT” to receive the air suspension treatment, but certainly won’t be the last. With our show season coming back to life in the Spring, many car owners like Frank will be getting air ride and all kinds of other modifications installed on their cars in the coming months. Once the warm weather hits again, it’s showtime!

Milestar Tires Introduces the MS932 XP+:
An Ultra-High Performance
All-Season Tire

Summer may be gone, but that doesn’t mean you can’t have high-traction in these cold months. Milestar Tires brings a new Ultra-High Performance All-Season Passenger tire with the MS932 XP+.

It seems like a case of “have your cake and eat it, too,” but tire technology has progressed to the point where having an all-season tire isn’t a performance detriment. With more sedans gaining exciting, sporty variants and customers not looking for the inconvenience of changing wheels and tires during season changes, tire manufacturers have been developing tires that can stick but still carry a mud and snow rating. Milestar is no exception and introduces the MS932 XP+.

It all optimizes from the MS932 Sport and puts it into a new silica-infused rubber polymer. Injecting silica allows the rubber polymer to remain flexible under nearly all temperatures. To keep it sporty in both winter and wet conditions, the inside tread pattern is optimized to move water towards the outside tire edges. However, the wide ribs and large shoulder tread blocks retain dry traction in summer conditions. The wide grooves help reduce hydroplaning by giving water channels to flow into.

The 380AA rated rubber compound and plies under the tread allow it to retain a W-speed rating to match OE performance. With all of this performance, the MS932 XP+ is a comfortable tire to drive daily with low noise and great fuel efficiency numbers. Even so, it’s a long-lasting tire with a 40-thousand-mile limited warranty. The MS932 XP+ comes in popular performance sizes in 18, 19, 20, and 22-inch wheel diameters, so nearly every performance car will have a tire for them.

If you’re looking for a tire for your high-performance sedan, Milestar Tires has a new tire for you. The MS932 XP+ gives you the all-season performance with mud and snow rating without degrading dry performance. Find your local tire dealer and ask for a set of Milestar MS932 XP+ before winter hits in full.

All Surfaces, All Traction

What Is an All-Terrain Tire?

Want a tire that gives you traction no matter where you are? Well, that doesn’t exist but there is a tire that gives you great all-around traction with some compromises. That tire is the All-Terrain – or AT – tire, which used to be a single category until recently. We’ll go over the most common versions of the AT in this story.

Unlike the MT tire, the All-Terrain is a compromise between on-road comfort and off-road capability. AT tires don’t generally excel in either area but work at their best in either. They feature smaller tread blocks for the best on-road noise and wet surface grip, but the blocks are still large and aggressive enough to be used in dirt and light rock off-road conditions. However, there has been a change in how an AT tire is designed and now there are two types of tire designs within the AT tire class. Each type of AT gets closer to the MT design.

The classic AT, like the Patagonia A/T W, is designed with more on-road performance than off. Some will call this an AP (All-Purpose) or Trail type All-Terrain but there is a specific All-Purpose tire category. So, calling an AT an AP tire is technically wrong. This is mostly because it’s capable of going off-road, but its smaller tread blocks and grooves allow mud to “stick” to the tire more. This reduces traction in that condition, but the smaller tread and harder tread compound mean that it won’t do well in rock crawling conditions.

The tread also doesn’t travel down into the sidewall and it features fewer belts than the MT tire. The sidewall ply and bead design will also only allow for normal tire pressures of 30-PSI and above. When people think of “truck tires,” like what you’d see on mid- and full-size pickup trucks and SUVs, this tire design is what they will picture. It’s perfect for trucks and SUVs that don’t see much off-road action, but if it does, it’s only going to be down a dirt road.

The next step in the AT ladder is the AT-X or AT-R tire. This type features larger blocks than the standard AT and you can see this in the Patagonia A/T R. The tread blocks are much more aggressive and somewhat larger, and the sidewall of an AT-X has some tread, but not to the extent of a full MT tire. It also features more siping than an MT, but not as much as the AT. Again, the siping is there to reduce squirm and improve wet road surface traction by giving water an evacuation path. The AT-R or AT-X type All-Terrain tire is perfect for vehicles that see more off-road surfaces but still travel mainly on surface streets. It’s probably not going to work well as a rock crawler or dune tire, but you’ll be able to get to your favorite off-road and camping spots with no issues.

What both types of AT tires feature is reduced road noise. This is an integral feature of any tire that has smaller tread blocks and more grooves and sipes. When the tread rotates onto the road surface, it compresses the air. That loads up air like a spring and when it escapes, it does so at Mach speeds from the energy it gains from being compressed. If the air has a path or pocket to escape to, it reduces that compression and potential energy. That slows down the air’s speed and you no longer hear the howl as you do of an MT tire.

The AT tire is the best compromise of on-road manners and off-road capability. You’re not going to be crawling up Jackhammer with either AT tire, but you’ll produce less noise than the MT tire. You’ll be able to get to a spot where you can watch your favorite Ultra4 racer and drive home with more wet surface traction than the mud tire. If you want more off-road traction, then the AT-R or AT-X will be a better choice. You’ll get a more aggressive look than the AT and better performance off the asphalt, too. However, if you need absolute off-road traction, then you’ll have to consider something more aggressive.

Max Traction

What Is a Mud Terrain Tire?

When you think of the ultimate off-road machine, you probably imagine it having Mud Terrain – or MT – tires. What makes an MT such a specific tire? We’ll answer that today.

A Mud Terrain tire, like the Milestar Patagonia M/T, is designed for extreme off-road terrain. Despite its name, the MT is used in more than just muddy conditions. The focus of this tire type is debris ejection, be it mud or stones. Clearing out the grooves naturally with tire rotation allows the tread block leading edge to grab the next portion of the surface and “claw” through it. So, the grooves act sort of like a scoop. Otherwise, the grooves fill up and the tire loses traction.

However, an innovation made by Mickey Thompson in the 1960s and featured on nearly every MT tire since is the sidewall tread. Allowing the tread to continue down the sidewall of the tire gives the MT another area for traction in rocky and silty sand conditions. When aired down, the MT’s sidewall tread also helps to increase the tread width as the tires flatten out under vehicle weight.

Because it’s made to be aired down, the MT tires carcass is also designed much differently than a regular street tire like the Milestar Grantland. It typically features more belts to deal with the additional stress airing down creates on the sidewalls. Those belts are also designed to flex despite adding more of them. The beads are also designed to hold on to the rim at lower pressures, usually down to about 20-PSI before needing beadlocks. However, that’s not true for all MT tires. Some can go lower, some can’t go that low without a beadlock. Again, it’s up to the design so always follow the recommendations and warnings from your tire.

One of the biggest down falls of the MT tire is noise. Large tread blocks compress air into the ground, putting it under extreme pressure at the microscopic level. When the tread rotates, that highly compressed air shoots out at Mach speeds and creates the howling noise that’s typical of a very aggressive and blocky tread pattern. The other disadvantage to those large tread blocks is squirm, traction in wet road conditions, and rubber compound life.

Squirm is the movement of the tread on the road surface as the tire drives down the road. Because of its large size, the large lugs will squirm more and create heat. That heat travels through the lugs to spots where it can’t cool off and creates hot spots. The combination of squirm and hot spots creates weaknesses in the lug and can cause chunking. Squirm is typically worse on the steering axle than the drive axle, but the drive axle can still see some squirm as you accelerate on changing road conditions.

Despite its great off-road traction, wet asphalt or concrete surfaces will be its weakest points. Those large tread blocks with no grooves have a reduced amount of water removal. While the water can travel around the blocks, the blocks contacting the surface is trying to squish down water that’s between it and the road surface. Since the water is a nearly incompressible fluid, the tread rides above the surface. This is hydroplaning, which reduces traction to zero because the rubber can no longer form with the road, which is what creates grip.

A tire’s rubber compound, which arbitrarily describes the softness or hardness of rubber in tires, can also increase grip if its softer. Many MT tires are softer than their road cousins due to the requirement of traction in sand and rocks. That also means that a MT tire won’t always last as long as regular road tires. Not always, but a majority will not.

However, modern MT tires like the Patagonia M/T are designed with mixed surfaces in mind. So, while the tread blocks are still larger than a standard road tire, they feature additional grooves and purpose made sipes. The sipes allow the tread to move in smaller sizes, reducing the squirm when compared to a fully solid tread lug. The combination of grooves and sipes also helps in removing water so the tread can grip on wet asphalt and concrete roads. They also help reduce road noise by giving air an escape route before being compressed into the road.

Do you need a MT tire? Maybe. Maybe not. The only way to answer that is to ask yourself this question. “Where am I using my vehicle the most?” If you’re mostly running on surface streets with little to no off-road use, then you don’t need a MT tire. If you’re response is the opposite, how often are you on those off-road conditions and can you deal with more road noise produced by those tires? If you just want a tire that looks cool and don’t care about noise and wet surface traction, you can’t beat the aggressive looks of the MT but there still might be a tire right for you that isn’t a MT.

Shocking Results

The Shock Absorber Theory

On-road or off, your shock absorbers control how your ride feels and behaves while in the dunes or on track pulling high-g’s. For this first article, we’ll look at the basic idea of shocks, talk about the twin-tube and mono-tube varieties, and how external shock adjusting works.

The damper is probably better known to most people as a shock absorber or simply a shock. It is a device used to control the rate of pitch and roll of a vehicle. It also controls the rate of motion of a spring inbound (also called bump in racing or jounce in engineering terms) and rebound (also called droop in racing). Without them, your vehicle would just flop around as the springs would have no control and react to not only the road but also itself as it oscillates.

Think of those slow-motion videos of a valvetrain as the cams open and close the valves. Since those valve springs have no dampening control, they bounce and even cause “valve float.” That’s a topic for another day, but just know the same thing could happen in your suspension if you didn’t have shocks.

BASIC DAMPER DESIGN

Inside the tubes that make up your shocks is a shaft with a disc connected to the end of it. This is the piston and it has a stack of shims on top of openings cut or molded into the piston. This in combination of flowing through hydraulic oil is how your shocks dampen the springs movements. It sounds simple enough, but there is far more going on than you probably still realize.

THE HOLES AND SHIM STACKS

First, let’s start with the piston design itself. If you’re into RC car racing, you are familiar with how the holes in those pistons control how fast or slow the piston flows through that fluid. The amount and size of those holes partially determine the damping rate. Next are those shim stacks, with a set on top and on the bottom of the piston to further control bound and rebound independently.

The thickness and amount of those shims will further increase or decrease the damping rate on each side of the piston. That’s also why those holes are enlarged and staggered at the face of each side of it. This is so the fluid can flow around the opposite stack, though the piston, and then on to the stack that controls bound or rebound.

DIGRESSIVE AND LINEAR PISTONS IN SHOCK ABSORBERS

The piston face can further control the dampening rate by using a digressive or linear face design. A linear face design is flat and the shim stack acts without any further changes in the reactive speed of the stack. A digressive face piston is dished to allow for preloading of the shim stack to change the dampening rate during slow damper shaft speeds.

To explain shaft speed, think of your vehicle diving down and returning to normal during a stop versus hitting a set of quick bumps in the road. The piston shaft is moving at a slow rate during stopping while it moves quickly during bumps because it’s moving more in a shorter amount of time. That preloading of the stack delays its opening and increases the dampening force during those low shaft speeds. A shock absorber with this type of piston makes it a speed-dependent dampener and a piston can be linear on both sides, digressive on both sides, or digressive and linear on each side. How that’s done is determined by testing on a shock dyno and even driver input for motorsports.

BAD GAS

Now, if you were paying attention in physics class while in high-school or even college if you went, you probably start to see an issue with the piston moving through that fluid. It creates a high-pressure side and a low-pressure side. As the piston moves through the fluid, the “top side” (the side with an inactive shim stack) must force its way through and creates an area of high-pressure. If it was a gas, it would move somewhat freer but wouldn’t act like a good damper.

However, that’s not the issue. The side the piston shim stack is acting on creates a low-pressure side. If you’ve ever boiled water at sea level and at high-altitude, you know that water boils faster at higher altitude because the atmospheric pressure is lower. The exact same thing happens in your dampers.

This is the primary cause of aeration; the shock oil degasses due to low-pressure pulling gas out of solution (also known as vacuum degasification) and even begins to boil the oil on the “bottom side” of the piston as the shock heats up. These gasses cause a feeling of reduced dampening because gas is compressible whereas a fluid is non-compressible.

NON-COMPRESSIBLE FLUID

The fluid being non-compressible is the whole reason a shock works while gas being compressible is the reason why air ride suspensions work. Gasses create a spring force when compressed and are how and why a suspension airbag works in place of a spring. However, you don’t want that in a shock.

You want a fluid that is non-compressible, however, you also want something that will allow the piston to flow through itself but won’t entirely stop it when the rate changes. That’s why a non-Newtonian Fluid like oobleck, for example, wouldn’t work. You could use simple friction and early dampers were designed that way (like the Andre Hartford design), it doesn’t dampen as well as oil does. That’s why a fluid like shock oil has been used in dampers since 1907 and we must give thanks to Maurice Houdaille for its invention.

GOOD GAS

So, how do you prevent the shock absorber fluid from boiling or degassing if it’s our only choice? Simple, by maintaining a constant pressure on both sides of the piston. That doesn’t sound possible, does it. Fortunately, it is by using nitrogen gas to create constant pressure. While you don’t want a gas as your dampening fluid, you do want it to keep the fluid pressure in the damper constant by utilizing its natural spring force.

This natural spring force also allows fluid to react as the piston travels through it. It gives it space while keeping the pressure equal on both sides of the piston. Even though there are holes in the piston, the fluid will still displace until the shims open or it hydrolocks and, just like when your engine does it, that condition can cause catastrophic damage to the damper.

Even so, it is still possible to hydrolock during high shaft speeds and why your vehicle feel like there is a solid block instead of a spring on certain bumps. That can also be solved in piston design with extra holes (like you see on King Racing Off-Road Shocks) or with shim designs that allow fluid to pass (like what’s used by Eibach).

GASSING PRESSURE IN A TWIN-TUBE VS. MONO-TUBE

A twin-tube damper, which uses a tube within a tube design, does mix the nitrogen with the oil, but because it’s at a low-pressure and its molecule is larger than oxygen, so it doesn’t fully mix (or gets dissolved into solution, as they say in science) with the shock oil. It still does, but the amount is small enough to not be an issue for twin-tube dampers. It also has the benefit of being inert, reducing fire risk, and cheaper than other inert gasses as you can pull nitrogen out of the air over argon.

The working cylinder, as the name implies, is where the piston and shock oil work. The outer cylinder, the one you see and touch as you install your dampers, is where the excess oil goes and where the nitrogen lives. A valve between the working cylinder and the outer cylinder allows fluid to flow between them and works as another dampening force control valve.

In a mono-tube design, the body is the working cylinder and that’s it. However, the nitrogen gas is separated by a floating piston that also has a seal to keep the gas contained above that piston. Because of this, the nitrogen doesn’t mix with the shock oil like it does with a twin-tube design. You can typically use the nitrogen gas at much higher pressures because of this separation, as well, which further reduces aeration by degassing and boiling by low-pressure at the piston. A mono-tube also allows for a larger piston – providing more surface area for the oil to work with – and better cooling as the fluid makes direct contact with the cylinder while working and transfers heat away much more effectively.

ADJUSTING DAMPENING FORCE

As mentioned earlier, the dampening force is dependent on the piston’s design and the way the shims react as it flows through the shock oil. However, it is also possible to adjust that without tearing apart the damper. The primary way this is done in most mono-tube and several twin-tube damper designs are by allowing the shock oil to bypass the piston. For these Eibach dampers, there are two holes drilled into the damper shaft, one or more above the piston and one through the center of the shaft at the bottom of the piston. The shaft is also drilled through with a rod or needle passing through it.

When the damper uses a rod, it connects to a pod at the bottom of the shaft and a rotating disc that has different sized holes for the oil the flow through. A ball detent not only gives the user an audible “click” to know where they are in their adjustments but also aligns the rotating disc’s holes to the holes of the pod. While simple, this design also limits the adjusting capabilities by only having so many holes to choose from.

In the needle design, the hole goes straight through the damper shaft at the bottom of the piston. Rather than using a rotating pod, a needle limits the opening inside the shaft. It works much like a carburetor needle does by gradually reducing the opening of the orifice. While it does offer far more adjustability, it will eventually full close off the opening, so the adjustment is finite. Another advantage is that the taper of the needle can be modified to change how much and how fast the needle reduces the orifice opening per knob turn before going fully closed.

ADJUSTABLE EXTERNAL RESERVOIRS

External oil reservoirs can also add an additional way to control dampening force by limiting how much fluid flows between it and the damper as it is displaced by the piston. On some shocks with an adjustable reservoir, a ball-detent controlled dial changes the preload the shim stack inside it. This sits on top of what looks like a piston, but instead of flowing through the fluid on a shaft, it’s fixed to the adjuster and fluid flows through it.

Because of this, the nitrogen, along with a floating piston, is in the reservoir rather than the damper body. This still works the same way as it would if it was inside the damper body, the pressure is still maintained by the nitrogen and floating piston. This is also how the twin-tube adjuster works. The base valve between the reservoir cylinder and the working cylinder would work and be adjusted in the same manner.

However, adjustable external reservoir twin-tube dampers do exist. Some don’t have a base valve, and some do but either way, they work very differently from a mono-tube external damper. It does borrow a little bit from the mono-tube external with the nitrogen gas being separated by a floating dividing piston inside the reservoir. Another design is to use a nitrogen bladder over a piston. It’s how the fluid goes from the outer and working cylinders that makes it very different.

What you can’t see is that there are two paths for shock oil to travel. One path is just for bound and is open to the working cylinder while the other is for rebound and is open to the external cylinder. Oil flow control is done by a piston with a spring and rate is controlled by adjusting the preload of that spring. The higher the preload, the more force is required to push the piston open and vice versa. Because of this unique requirement, the reservoir is usually fixed and is part of the damper cap. There are remote external reservoir versions, but these feature two reservoirs rather than a single because the flow must be separated between the two cylinders.

What Are LED Lights?

If you want bright but don’t want lights the size of Texas, you didn’t have much choice but to buy HID lights for your specific needs. However, a new light has been on the market and has constantly gotten better and less expensive with age. It’s the LED Light.

LED, or Light Emitting Diode, is the latest and greatest technology in lighting now. It uses a two-lead semiconductor light source that works like a p-n junction diode. If you don’t know what that is, imagine two plates sandwiching two types of conductive material. One material has electrons from the voltage applied to it while the other material has electron holes. When enough voltage is applied the electrons recombine with the holes and produces energy in the form of photons and you get light.

With halogen and HID, you can’t combine multiple patterns into one light source. You can’t have one eight-inch light that was both spot and driving – it’s one or the other. With the size of LEDs, you can get many different light patterns on the same source. Despite how bright they are, LEDs are very small usually no smaller than your pinky nail (or smaller if you have big hands). That yellow dot you see on most light circuit boards is the LED. Despite its diminutive size, it has the brightness and power to outclass many HID lights you see right now. Thanks to that you can package a very powerful light system on your vehicle without having to clutter it up.

The other bonus it has over HID is that it’s instant power up – you don’t have to wait for the plasma to build and warm up because there isn’t one. However, even LEDs, for their size and positives, have some drawbacks. LEDs are prone to producing more heat and manufacturers must take that into account when designing their lights. That includes the housings and circuit boards. That’s what adds costs to the housings because it must be waterproof, the LED can’t be exposed to outside elements, and there can be vibration issues. Even with its high cost, you can’t take away that its instant power, it can last 50-thousand-hours (if you buy from a reputable manufacturer), and you can buy fewer lights but can light up more areas.

So, if you’re looking to get your first set of off-road lights, which way should you go? Should you still use halogen? Save a little more for HID? Or are LEDs the better investment? While there will always be other factors, saving your money and getting a good, high quality LED setup isn’t a bad idea. It’s getting to the point where it’s not worth investing into a halogen or HID system because you can get so much more performance and longevity out of an LED.

With halogen lights, you get 250- to 300-hours of life out of them. With HID, it’s 3- to 5-thousand-hours. LEDs from a reputable company that engineers the product from start to finish will last up to 50-thousand-hours. You’ll probably go through several cars with a quality LED light. The only limitation is if there is an LED application for your vehicle outside universal products. However, there is always someone who makes an LED bulb to replace your headlights, fog lights, turn signals, and many other lights.

LED lights are the future for everyone. Initially more expensive than halogen and just about the same cost or just a little less expensive than HID, LEDs feature a longer life and better performance than either one. If you’re considering going LED for your project, it should be no brainer. Just be sure to purchase yours from someone you can trust, and you’ll get a long life out of it. Maybe even longer than your car lasts.

What Are Halogen Headlights?

It was the revolution that brought about the modern headlight. However, what is this mysterious thing called the Halogen Light Bulb?

Halogen lighting is the typical light you see on most vehicles that aren’t a premium brand. From headlights to fog lights to auxiliary and off-road lights; halogen is the inexpensive go-to for lighting on nearly anything with wheels. Essentially, the way it works is that there is a tungsten filament that heats up and burns to produce light. Normally, that filament would evaporate away until either the bulb was black or it broke. Halogen creates a reversible chemical reaction cycle with the evaporated tungsten and allows it to stay at the same output until it eventually burns out, usually after 250-hours.

Headlamps in the US were basically locked to the standard filament bulb from 1940 to about 1968 and the establishment of the National Highway Traffic Safety Administration (NHTSA) and the Federal Motor Vehicle Safety Standards (FMVSS). Europe, however, wasn’t locked to a standard and introduced the first halogen lamp for automotive use in 1962 with the H1 bulb. Even though it was proven to not only be a better light that lasted longer than the sealed beam, they were prohibited in the US. Once the fuel crisis hit, US lawmakers began to face pressure from the public and automobile manufacturers alike to finally allow new headlight standards and the “new” technology of the halogen bulb.

However, halogen lighting was limited to being stuck inside a sealed beam until the 1980s and the introduction of the 9004 bulb. The original H1 bulb, the one Europe had since the 60s, wasn’t approved for use in the US until 1997. Since then, we’ve had a slew of H-types used and approved in the US. What we’ve also gained are more aerodynamic front ends that allow for better fuel economy and performance.

Though, this also meant we lost the iconic pop-up headlamp in 2004 with the C4 Corvette and the Lotus Esprit ending production in that year. With smaller, slimmer shapes, the need for lowering the headlight to match the drastic angle of the front end was no longer required. Housing designs and better reflectors, along with the increased candela power of halogen bulbs, no longer mean we had to have a big bulky light on the nose of our cars and trucks.

Halogen bulbs are a great and inexpensive way to get lighting if all-out performance isn’t critical and you’re fine with changing a bulb. However, if you’re looking for more power and are approaching speeds of over 100-miles-per-hour, you really need a High-Intensity Discharge, or HID, light. That being said, the halogen light bulb probably isn’t going away for some time yet.

What Are HID Lights?

If you’re going fast, anything over 90-MPH, or setting off in the pitch dark of the desert, you need a light that will keep up and put light far down range. You need the High-Intensity Discharge (HID) light.

To get light beyond the mid-range you need lights that are brighter than what even a 100-watt halogen is capable of. “The HID Light opened up the entire world of what a light can do and being able to drive off of it,” says Trent Kirby, operations manager of Baja Designs, “because it produced more performance and a brighter light in the same power consumption of a halogen bulb, it opened up the world to distinct types of beam patterns. It allowed us to go beyond your traditional Euro beam and spotlights.”

What makes an HID perform better and brighter is that, instead of a halogen/tungsten chemical reaction, it uses the electrical arc of two tungsten electrodes inside a tube filled with gas and metal salts. Once that arc starts, the metal salts become plasma and increase the light produced by the arc and begin to reduce the power consumption of the light. The ballast you must use is needed to start the arc and maintain it, but the power required to drive the ballast is within the typical automotive electrical system including vehicles that used halogen lights originally. It also lasts longer than halogen with most systems lasting to about three- to five-thousand-hours.

An HID system does come with some complications over a halogen bulb and you must think of things like packaging, waterproofing, and dealing with the initial surge and warmup of the plasma inside the bulb. There are a couple of different configurations of HID lights. One is where you have an external ballast and that sits near the back of the light or you can put it in the engine bay. The other allows you to have an internal ballast.

The internal ballast has a huge advantage for harsh conditions because it won’t allow the ballast to be exposed to the environments, especially off-road drivers because that decreases reliability and longevity versus an exposed ballast. It can also make for one less part to have to package, but the internal ballast light might be bulkier. Again, it’s something you must plan out when building your lights.

One of the first cars to appear with HID lights was the 1991 BMW 750iL in low-beam only, known as Litronic. The 1996 Lincoln Mark VIII was the first effort by a US Domestic manufacturer and was the only car with direct current (DC) ballast HIDs. Most ballasts at the time, and in use today, use an alternating current (AC) inverter. This allows the current to flow through both electrodes. While DC allows for simpler ballasts, it does wear the electrode that gets constant power more quickly whereas AC can allow for more equal wear, fewer fluctuations, and reduction in flicker.

Even so, the light you get out as either a headlamp or an auxiliary light like a fog or off-road light allows you to see much further than standard halogen bulbs. Never mind the advantage over the sealed beam filament light. If you need to send light beyond halogen light or you’re approaching speeds of over 95-MPH, it’s time to start thinking of better lights and start with HID.

What Is an Intake Manifold?

State of Speed Basics – The Manly Science of Automotive Knowledge

Spend any time hanging around with gearheads and you’ll hear the term “intake manifold” thrown around, usually in the context of a discussion about the merits and weaknesses of various designs. What does an intake manifold do? It’s simply the piece of plumbing that connects the intake ports on the cylinder head to the carburetor or throttle body, distributing fresh air (and sometimes fuel – more on that in a minute) evenly to each combustion chamber. The design of the intake manifold has a profound effect on the performance of the engine, helping to determine whether it’s happiest at high RPM or churning out torque down low, and with some clever engineering it can even broaden an engine’s powerband far beyond what a simple, single pipe connecting an individual throttle body to the cylinder head can provide. 

The intake manifold for a multi-cylinder carbureted engine, like a classic domestic V8, has a few main jobs to do. It has to evenly distribute air to each cylinder, do the same for the fuel atomized by the carburetor, and have enough internal volume to keep the carburetor happy since it works best when it feels a consistent ‘pull’ of vacuum drawn by the engine as it runs. Manifolds for carbureted engines are referred to as “wet” because the air flowing through them has fuel mixed in, and they have to be designed without sharp turns or twists that might cause fuel to separate out as it tries to make the corner along with the airflow. 

“Dry” manifolds for modern EFI or direct injection engines have an easier job; they only have to evenly flow air, and can be a little more convoluted without ill effects. But wet or dry, there are some design elements both share. Ideally, an intake manifold should provide as little resistance to airflow as possible at wide open throttle – imagine sucking air through a straw, compared to breathing through a paper towel tube. If that was the only consideration, you’d just make the runners as big in cross-section as possible, but moving air also has inertia and velocity, so the diameter of the runners has to be a compromise between being large enough to have low resistance under high demand, but small enough to keep that column of air moving as rapidly as possible to help push out exhaust gas and completely fill the cylinder during the intake stroke. 

Runner length is also important; all other things being equal, longer runners boost torque at low RPM, while shorter ones favor horsepower at high revs. Many factory intake manifold designs take advantage of this by having internal butterfly valves that allow the engine to switch between long and short runners, or even have separate runners for multi-valve heads that employ variable camshaft lift, duration, and timing. Finally, plenum volume is important – this is the “reservoir” that all the individual runners draw from, and changing the size of the plenum can also profoundly influence an engine’s powerband. 

Some modifications, like “port matching,” a process where an intake’s individual runners are hand-shaped to precisely conform to the cylinder head’s intake ports, will benefit any engine. More extreme changes to runner length and diameter, plenum volume, and even the interior finish of the manifold are most useful when they’re part of an overall plan for the engine build. A race manifold won’t help an otherwise-stock street engine – in fact, the wrong manifold will often kill performance. Before contemplating a change to your engine’s intake tract, make sure you understand what the effects will be, and how it will interact with all the other factors of your combination, including camshaft grind, displacement, desired peak RPM, and even transmission gearing. 

An intake manifold’s job is to connect the throttle body or carburetor to the intake ports on the cylinder head(s). Individual runners connect the plenum (the central, shared space) to the ports, and their length and cross-sectional size play an important role in determining the power band of the engine. This manifold is a Weiand “dual plane” design for V8 engines that is designed to provide very streetable power delivery characteristics. Notice the “waffle” pattern at the bottom of each plenum – this is an intentional feature that helps keep the fuel and air consistently mixed on their way to the cylinders.

This Weiand V8 manifold is a “single plane” design with short runners and all eight cylinders feeding from the common central plenum. These kinds of manifolds are optimized for maximum horsepower at high RPM, but sacrifice torque down low. 

This aftermarket Honda B series manifold from Edelbrock has relatively short runners connecting the intake ports to the plenum, optimized for free breathing at high RPM. Notice how close the injector bungs are to the flange that bolts to the cylinder head – fuel sprays directly at the back of the intake valves, and doesn’t have to travel any distance through the “dry” intake manifold runners. 

Edelbrock’s Honda D series intake manifold has longer runners designed to match the more torque-biased design of that engine family. Long, narrow runners will encourage airflow velocity, which helps the cylinders fill completely at lower RPM. 

Check out this aftermarket Honda manifold – here, the injectors are placed higher up in the runners, which allows a little bit more time and distance for fuel to atomize before flowing past the intake valve.

Many factory and even aftermarket intake manifolds are made of composite plastics rather than cast aluminum. Because they act as a kind of insulator, they can keep intake air cooler than a metal manifold for the same engine. This is a CAD illustration of FAST’s intake manifold for LS V8 engines, and it shows the unique three-piece design that splits into an upper and lower plenum housing that conceals individual intake runners. 

A look inside the FAST manifold with the top removed shows the individual runners. They all draw air from the same plenum, but FAST offers different runner lengths to fine-tune the manifold’s performance to match an engine’s power band. 

What Is EFI?

State of Speed Basics – The Manly Science of Automotive Knowledge

In order for an internal combustion engine to run, you need to have some way to mix fuel and air together in the right proportions – too much of either ingredient, and the engine runs badly if it even runs at all. To make things more complicated, the right mixture is constantly changing all the time, depending on load, engine RPM, and even the weather. For most of automotive history, carburetors took care of this essential task but as the world demanded cleaner and more fuel-efficient engines, those complicated mechanical air/fuel mixers just couldn’t provide the precision and flexibility required and electronic fuel injection came to the rescue. So, what is EFI and how does it work?

At its most basic, an EFI system simply measures or calculates the amount of air an engine breathes, applies some logic that tells it how much fuel needs to go with it in order to burn properly, then adds that fuel to the intake air. Some EFI systems directly meter all the air that flows past a sensor – these are often called “mass airflow” for obvious reasons. Others, called “speed-density,” calculate how much air is moving through the engine based on factors like engine RPM, air temperature, throttle position, and what’s known as “volumetric efficiency” – a measurement of what percentage of the theoretical maximum airflow is actually making its way into the cylinders at any given moment. 

No matter which strategy the EFI system uses to calculate airflow, an oxygen sensor in the exhaust pipe provides feedback to the computer to help refine the air/fuel mixture. This “closed loop” operation gives the EFI the chance to continuously correct itself to compensate for any disagreement between the programmed fuel supply and what reality actually demands. The tweaks the computer learns during closed loop operation often carry over to “open loop” situations, like when you are at wide open throttle and full power. This means that an EFI engine is constantly adjusting itself to match the conditions. 

In the hands of a skilled tuner with the right software, EFI provides the opportunity to change how an engine runs with the click of a mouse and the alteration of a few numbers in a table, but for most of us, it just means that our cars run better, get better gas mileage and make more power, and start on a cold day at the turn of a key. 

Back in 1957, Chevrolet introduced Rochester mechanical fuel injection as an option on the Corvette, but the system was so temperamental to tune and so few dealership mechanics were trained to take care of it that many owners scrapped the entire system and replaced it with a conventional carburetor. Today, original Rochester “fuelie” setups are worth thousands of dollars whether in working condition or not.

During the transition from carburetors to electronic fuel injection in the late 1980s, many manufacturers used “throttle body injection” where the computer controlled a few large-capacity injectors located where the carburetor would be in an older engine. This was a very practical way to gain most of the advantages of EFI with the fewest changes necessary to the existing engine design, and today, throttle body EFI conversions like this one from FiTech are a popular way to upgrade to electronic fuel injection. 

All modern factory electronic fuel injection systems use an oxygen sensor (and often more than one) to determine the engine’s actual air/fuel ratio by sampling the exhaust gasses. This allows the EFI to continuously correct the ratio to deliver exactly the right mix for the conditions. Factory EFI systems used to rely on ‘narrowband’ sensors that could only signal whether the exhaust was rich or lean of the 14.7:1 air to fuel mixture that represents complete combustion, but today’s OEM engines (as well as aftermarket EFI systems) use more sophisticated ‘wideband’ sensors that can accurately measure a much broader range of lean or rich ratios.

This high-performance aftermarket EFI system from Edelbrock features sequential port injection – there is one fuel injector per intake runner, and the computer activates it in time with the opening of the intake valve for maximum precision. Some dedicated racing port fuel injection systems even have more than one injector per cylinder, with a small-capacity one providing very precise control at part-throttle and a large capacity injector that takes over at wide open throttle.

Electronic fuel injectors come in several standard shapes and sizes, as well as different flow capacities to match engines ranging from motorcycles to turbocharged Pro Mod dragsters. They all have one thing in common, though – they act as electronically controlled valves that deliver a precise dose of fuel on command, supplied from a pressurized fuel rail. This Holley injector is an older factory-style design that is still popular with racers thanks to its durability and high maximum capacity.

What Is a Carburetor?

State of Speed Basics – The Manly Science of Automotive Knowledge

There are three things necessary for an internal combustion engine to operate – Fuel, air, and a source of ignition. For most of automotive history, one piece of hardware controlled two of the three required elements: the carburetor.

At its most basic, a carburetor is any device that combines fuel and air into a mixture that will support combustion. In Perfect Chemistry Land, gasoline wants 14.7 parts air to each part fuel for a complete burn, but because engines don’t visit Perfect Chemistry Land very often, a carburetor has to be able to deliver air/fuel mixtures that are both leaner (more air) and richer (more fuel) than this perfect “stoichiometric” 14.7:1 ratio, depending on many different factors.

Sometimes the ratio will need to change for better fuel economy, or for maximum power. It will have to be different when the engine is cold than it is when the engine is up to its normal operating temperature. And it will even need to change moment to moment as the throttle (the “butterfly” valve connected to the accelerator pedal that controls how much air passes through the carburetor and into the engine) changes position.

In order to do that smoothly and effectively, carburetors evolved from simple devices that vaporized fuel into what are essentially sophisticated analog computers. The main data inputs are the manifold vacuum and throttle position, which represent how much air the engine is trying to draw in, and how much air the driver is allowing it to have, respectively. Based on these two primary factors, a complex series of air passages, calibrated orifices called ‘jets’ or tapered metering rods, and any number of other clever mechanical devices controlling the flow of air and fuel work together to deliver the correct mixture to the engine.

Carburetors fell out of favor for factory vehicles in the late 1980s as electronic fuel injection became available (and less expensive), with the last carbureted vehicles sold in the US bowing out in the early ’90s. Manufacturers found that EFI made it easier to comply with tighter emissions requirements, but in the world of high performance, carburetors still enjoy a lot of popularity for both street and race vehicles.

The Holley 4150-style carburetor is easily the most well-known performance carb and can be found on countless different factory muscle cars and race vehicles.

Edelbrock’s AVS carburetors are an update of another classic 4-barrel carb design. This polished show-quality model features an electric choke – the black cylinder on the left side of the carburetor contains a mechanism that automatically opens and closes the choke based on the electrical signal from a sensor installed in the engine’s cooling system.

Holley’s ‘Dominator’ 4500-series carburetor is the big brother to the classic 4150, designed for engines that need more airflow than a smaller carburetor can provide.

Carburetor Terms You Should Know

The appeal of a carburetor to a gearhead is that all the necessary tuning can be done with a selection of simple parts and a few hand tools – no laptop (and no electricity, period!) is required to make adjustments. Racers will typically take careful notes of how an engine performed under specific air temperature, barometric pressure, and humidity conditions with certain carburetor settings and parts in order to make it easier to reproduce the correct tune in the future and predict how changes will affect engine power and responsiveness. 

While carburetors have been around for more than a century, they still have a prominent place in high-performance engine tuning and will be around for many years to come in both racing applications and under the hood of classic cars from around the globe. 

Carburetor Glossery

• Choke: A movable device at the inlet of a carburetor that is designed to restrict airflow and richen the air/fuel mixture for better engine operation while cold. Many racing carburetors have no choke, as it can cause a restriction to airflow even when deactivated. Engines equipped with chokeless carbs are harder to start and require constant attention to the throttle to keep them running until they reach operating temperature
• Side-Draft/Down-Draft: Depending on the layout of the intake manifold, carburetors may be designed to flow air and fuel horizontally (side-draft) or vertically (down-draft). Side-draft carburetors are common on classic Japanese and European cars, while American V8 cars are typically down-draft.
• 2-Barrel/4-Barrel: Muscle car carburetors will often be referred to by the number of “barrels” or venturi intakes the carburetor has. Often abbreviated as “2/4bbl” or “2v/4v”, 2-barrel carburetors were most often found in lower-performance applications, while high horsepower engines featured 4-barrel carburetors, or even multiple 2- and 4-barrel carbs.
• Vacuum/Mechanical Secondary: In a 4-barrel carburetor, the engine normally draws air from only two of the four venturis. This allows more precise fuel metering than if all four were in operation at all times. In a vacuum secondary carb, the main throttle blades are controlled directly by a mechanical connection to the accelerator pedal, but the secondary blades on the other two barrels only open in response to a vacuum signal from the manifold that indicates the driver is at wide open throttle. A carb with mechanical secondaries has a mechanical linkage that progressively opens the second pair of throttle butterflies in response to the position of the accelerator pedal. Vacuum secondary carbs are considered more “streetable” and deliver better fuel economy than race-oriented mechanical secondary carbs.

This Holley “Tri-Power” intake setup combines three two-barrel carburetors on a single V8 intake manifold for a cool vintage look and high performance to match. 

Many classic Japanese and European cars with inline 4 and 6 cylinder engines used the classic Weber DCOE side-draft carburetor. The side-draft design allows a very low hood line because the intake manifold and carburetors (often one per pair of cylinders in performance applications) don’t extend above the top of the engine. 

While you won’t need a laptop to tune a carburetor, you will need an assortment of different components like metering jets, power valves, accelerator pump squirters and cams, and other small parts. 

This Holley street carb has both a choke (the rectangular gold plate) for easier cold starts and vacuum secondary throttle blades (controlled by the round, silver vacuum diaphragm mechanism at the top.)