Enabling your Drivetrain to handle your “tuned” engine

Opening the carbon fiber hood of your ride, you gaze at all those engine mods you made, like the HKS fuel rail, the SARD fuel pressure regulator, the TODA cams and adjustable cam gears, the RC fuel injectors, and all the go-fast engine goodies that just goes on and on. However, come to think of it, can your engine’s drivetrain handle the additional power from all those mods? In most cases, we tend to concentrate all our efforts towards the engine alone and forget the other systems that must also be upgraded. Keep in mind that with newfound engine power comes a more aggressive driving attitude as well as hard launches and higher rpm’s. Now with that kind of abuse, something could get damaged and might give in without you knowing it, like your transmission, or differential. So before you start picking up shattered pieces of your drivetrain on the track or on the street, let’s look at some of the components that could use some upgrading.

The Clutch

Simply put, the clutch acts as the connection point between the engine and the transmission and serves as the main source of power distribution. Now if you subject your stock clutch with high-torque loads and high-rev launches from your “tuned” engine, sooner or later the friction material on the plate, which is there to help the clutch grab the spinning flywheel will get so hot and just glaze over that it will now be unable to latch onto the flywheel, resulting to clutch slippage and lost power. As a solution, there are various aftermarket clutch companies to choose from like Exedy, HKS, and Centerforce, just to name a few that offer performance clutches that are able to withstand high temperatures ranging from a stage one 500-degree street clutch all the way to the stage three 1,200-degree competition clutch depending on your needs. Now before you get any crazy ideas like running a racing clutch in a streetcar, better keep reading. Because as cool as it may sound, the fact is that racing clutches need to be really hot in order for it to engage properly, and the temperatures typically generated by a street car isn’t that high enough, so it would be useless running a racing clutch on the street. Aside from that, due to the stronger clamping force, there is an increased pedal effort, due to the stiffer springs installed on the pressure plate and the disc. Moreover, they do not have as much friction material as compared to street clutches in order to save weight, making everyday start and stop driving a no-no, as they will wear out quickly. Some people can tolerate clutch chatter, heavy pedal effort, higher cost, and extreme modification. But why tolerate unnecessary issues when you do not have to. So choose the right clutch with better friction material than stock that is fit for track use, and yet still remain suitable for everyday driving. Some people can tolerate clutch chatter, or noise, or heavy pedal effort, or shorter clutch life, or higher cost, or extreme modifications tolerate unnecessary

The Differential and the L.S.D.

Located within the transaxle, the differential allows the rotational speed of your ride’s inner and outer drive axles to differ as needed to go around corners. However, when it is subjected to hard acceleration, only one wheel starts to spin, and there will be no torque delivered to the non-spinning axle, hence the single tire mark you got on the road during your last burnout. Now if you want to maximize your power-to-pavement effectiveness, your diff will need a limited slip differential (LSD). Depending on the make, a limited slip differential can either be composed of small multi-plate clutches, planetary gears, or the viscous type that is made up of fluids, but is said to be less efficient than the former two. The LSD is able to transmit torque in a roughly 50-50 split between the two driving axles. So that when you execute your burnout this time, your car will now leave behind two trails of burnt rubber, and if your car has to go around a corner the clutch plates or the gears disengage for a while so that the axles can turn independently with one another.

LSD Lingo

1-way LSD – The LSD comes into use once the throttle is stepped on.

1.5- way LSD – The LSD comes into use once the throttle is stepped on and when the
car is braking there is a slight LSD effect.

2-way LSD – The LSD comes into use whether the car is accelerating or braking.

Sometimes you will hear these terms used in the business of L.S.D. trading and the racing d

Shorty the Shifter

While it does not have anything to do directly with your Drivetrain, a short-shift kit can definitely improve your transmission’s performance by reducing the amount of arm movement required to make lightning-quick shifts, as well as the time it takes to throw the shift lever between gears. Now this is a simple bolt-on affair utilizing basic tools that almost anyone can do, that won’t cost you an arm and a leg. Short-shift kits are able to minimize the gear throw by changing the mounting points of the levers as compared to a stock lever, so that a smaller movement of the lever is achieved to change gears. A word of advice to the newbies; you have to punch the pedal faster to match the new speed of your hands rowing through the gears.

To Lighten or not to Lighten?

It is a racer’s mantra to make everything light on his car. However, when speaking about lightened flywheels, there is a bit of hesitation. So let us analyze the process and effect. When one is to subject a rotating mass like a flywheel into a weight reduction, the result would be that it would spin faster, and therefore make the engine feel more responsive. Sounds right, but only to a certain extent. Now why is that? You see, a flywheel stores inertia, which keeps the engine spinning whenever the clutch is disengaged, so that it does not fall too far out of its power band between shifts. However, if one were to put an over lightened flywheel it will not keep up with the engine revs, and you will struggle to get back into the power band every time you up shift. Most tuners make use of this trick in tandem with a lightened crankshaft that have both been balanced, and flitted with a counterweight to maximize the potential of the engine. However if you do decide to install a lightened flywheel do take into consideration that it will NOT give you any more power, so top speed, will remain unchanged. Although it WILL allow more power to reach the wheels under accelerating conditions because less energy is wasted accelerating the engines rotating parts.

Front Wheel Drive Axles

Now I have seen a fair share of snapped and broken axles as a result of too much shock loads imposed by a much stronger motor than what they used to drive before. Therefore, since it plays an important role into putting power to the pavement, it would be best to check on the condition of your axles, along with the CV joints paying close attention to the trunnion bearings for wear if you plan to strengthen your motor. Now some tuners try to adapt a much beefier axle by using a larger one from a bigger engine of the same make, and if they do not have the same number of splines or a difference in bolt patterns, they just have it, custom machined in order to make everything fit together. However, if you really want he real deal, then there is always the Driveshaft Shop in the States. Using only aircraft-grade chromoly it can’t get any harder than that and their tripod joints for the CV are three times larger in diameter than the factory ones. The shop can custom fabricate a very strong axle, depending on your cars power output, whereby their level one axle is good for up to 225 hp, all the way up to their level 5 axle that is capable of withstanding 600-plus hp.

Now you can alter the camber settings on your car, anytime, anywhere, whether for street or track use.

Camber Basics

Before we begin, let’s give a rundown on what camber is and how does this affect your car’s overall handling. Remember that camber angle is made by the wheel that exhibits itself either as, positive or negative. More specifically it is the angle between the vertical axis of the wheel and the vertical axis of the vehicle when viewed from the front or rear.

Positive camber is achieved when the top of the wheel is further out than the bottom.

Negative Camber is when the bottom of the wheel is further out than the top.

Negative camber as this diagram suggests is typically found on vehicles that are set up for track/autocross.

Camber angles alters the handling qualities of any suspension design, in particular negative camber improves grip when cornering, at the expense of premature inner tire wear. However in most cases, it is usually desirable to have the car adjusted for neutral steer, so that it responds quickly to a turn of the steering wheel, like the settings on production cars where car manufacturers tend to err towards positive camber to deliberately instill understeer onto its handling as this is deemed safer for inexperienced drivers.

The most common handling problems are:

Understeer

This is the condition when the front tires experience a loss in traction during a cornering situation, thus causing the car to head towards the outside of a corner.

Oversteer

This is the condition when the rear tires experience a loss in traction during a cornering situation, thus causing the rear end of the car to head towards a corner.

Bodyroll

This is the condition when the car’s body leans towards the outside of a curve, whereby this situation can cause the wheels on the inside of the wheel to be loaded with less tire grip that will contribute to an over or understeer situation.

Camber Angle                   Reduce Understeer                               Reduce Oversteer

Front camber                Increase negative camber                 Reduce negative Camber

Rear camber                  Reduce negative Camber                  Increase negative camber

Adjustable Camber Plates

These plates replace the topmost portion of your McPherson strut or coil-over.  Located on its center is what is called the pillowball mount. This allows the strut to move in such a way that it can be adjusted for different camber settings.  There are 2 Allen head type bolts on either side, that when loosened will enable one to move the strut inwards (Positive) or outwards (Negative) along with the plate.  Also located on the pillowball mounting plate is a graded mark that signifies how many degrees and if it is either negative or positive with 0 as the center. Simply line up the marker with the one on the plate with your desired camber setting and then tighten up the 4 Allen head bolts and that’s all there is to it.

The Objective

Don’t expect a dramatic improvement in handling by simply dialing in way too much camber.  Remember that in order to achieve the proper camber angle, the initial camber setting must be sufficient enough to compensate for camber lost due to body roll and suspension design. High performance settings normally dictate more negative camber and more positive caster. This is because both of this will help keep the wide tires more upright during cornering, thereby maximizing the tire’s contact patch on the pavement. However, camber angles greater than 3 degrees negative will affect transient handling (Takes too long for the tire’s sidewall to roll over and flatten out) and is indicative of that one should make suspension changes elsewhere. Bottom line here is that the interaction between driving conditions and suspension limitations dictates compromise.

Pros

No more inconsistent handling

Improved turn-in feel

Keeps the contact patch wider on the pavement

Perfect for vehicles that see autocross and track days

Enhances overall steering feel

Cons

Bit costly, but effective.

Too much negative camber will result into increased rolling resistance.

New Tech

Adjustable Camber Bolts by H&R

H&R’s new Triple C camber adjusters are a simple, yet very effective means of removing excessive camber, adjusting your vehicle’s camber settings, or even correcting small side-to-side camber variations for precise alignment. Consisting of a pair of specially-designed bolts, H&R’s patented Triple C camber adjusters replace the original upper fastening bolts on all McPherson strut applications. As the bolt is turned, a small cam eccentric alters the vehicle’s camber, allowing adjustments from 0-3 degrees, positive or negative. Installation takes only minutes with readily-available hand tools, and benefits include increased tire life, improved tracking and the ability to dial in more camber for weekend track events.

Engine oils were made to clean, and lubricate engines. Advanced synthesizing and refining of lubricants have actually helped engines perform more efficiently while producing more power with less wear. Many engines today have in fact longer service intervals due to the advancement of lubricants, which makes cars use less oil throughout its service life.

It would be interesting to know also that not all oils are made equal. In a recent interview with Dr. Katsuya Arai, oil engineer for MOTUL Japan, we find out all about the company and what makes it different from other companies. Dr. Arai started with a little history of the company, which started more than 150 years ago in the whale oil business, which later evolved to developing some of the most advanced lubricants in the world. The company is based in France with subsidiaries and research facilities based in the US, Japan, Germany, Spain and Italy.

Dr. Arai also related that the company has been in Japan for more than 20 years collaborating with manufacturers and motorsports teams to develop lubricants for Japanese vehicles. He himself has been working together with the Subaru World Rally Team to develop lubricants for each challenging rally course they encounter. MOTUL’s participation in major motorsport events that include the FIA GT, Super GT, World Rally Championship.

MOTUL’s milestones actually include introducing some of the world’s firsts in the market. They were the one’s who introduced the first semi-synthetic lubricant in 1966 called Century 2100, and 100% synthetic lubricant ever designed for cars called Century 300V later in 1971. “Better than others” is the company phrase, which clearly shows in the modern 300V double-ester oil, which is one of the better if not the best oil in the market today.

Better lubricants also mean that your vehicles will run more efficiently, thereby providing a significant power increase and giving better protection at the same time. But of course, having high quality oil does not mean that you do not need to change your oil regularly. Dr. Arai reminds vehicle owners to follow manufacturer recommendations for lubricant replacement intervals to keep their machines in tip-top shape.

Recently introduced in the Philippines through AutoplusSportzentrium, MOTUL has become one of the most popular lubricant brands and is being used by some of the most demanding customers and top racing teams in drag racing, drift, formula 3, and touring cars.

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Suspension modifications aren’t done just to make your car look better. The factory suspension of our cars are designed to achieve smooth ride comfort while maintaining good handling. For the performance driver or enthusiast, good handling is more important than comfort. Take note that you cannot have excellent characteristics for both handling and comfort as there will always be a trade-off between the two.

Basic suspension modifications consist of springs, sport-tuned/performance shock absorbers, strut bars. Being basic, these are relatively easy to install and should not be hard to find as well.

Coil Springs

Springs were primarily used in the olden days of the automobile as the primary suspension. There are two different kinds of automotive springs, the coil and the leaf. Coil springs are manufactured of a special round steel rolled in a specifically engineered helix shape with the use of computer aided machines. Coils are usually used in cars, modern car suspensions in particular utilize coil springs and is considered to be a major improvement from leaf springs.

Coil springs support the weight of the vehicle and allow the suspension to articulate in order to provide a smooth ride over bumps and dips in the road. Most people will attribute worn coil springs will cause the vehicle to bounce excessively, which is a common misconception. The job of providing resistance to this bouncing is for the dampers or shock absorbers or struts, and not the coil springs. In any case, over time, as with any part of your car coil springs can break or loose their strength and need to be replaced.

One of the most basic performance upgrades for suspension is to change to lowering springs which will improve handling ability and aesthetic characteristics as well. Lowering springs are specifically engineered to give a lower ride height but at the same time maintain the capabilities of the suspension coiled to a specifications which have been researched by engineers. There are things to consider before changing to lowering springs of course. Firstly, the stiffer lowering springs may not ride as comfortably as the factory springs. Secondly the lower vehicle is more likely to hit the ground over humps and bumps which could result in expensive damages to the undercarriage and exhaust system. Lastly, the altered suspension geometry would most likely change suspension characteristics like camber in particular.

NEVER CUT or HEAT YOUR ORIGINAL SPRINGS just to achieve a lowered stance. Although this will lower your car, it will also destroy the coil spring during the cutting and will not provide the necessary resistance designed for your car. This will also give you a discomfortable and wobbly ride and could also cause unwanted damage to the suspension system which could amount to a lot of money.

Types of Springs

Sport Springs

Sport springs are designed to give the least compromise for ride comfort while giving a slightly lowered ride height. These springs offer improved front-to-rear balance and street handling perofmrance. They were designed to take the wallow out of the stock suspension to give a more stable feel and imporved ride characteristics. These springs are designed to be installed with the stock shocks.

Race Springs

Race springs are designed to be more aggressive thus higher spring rates and a lower ride height is also expected for a lower center of gravity. Thus, the design follows with the type that these springs are not recommended for use on the street as they will not be comfortable at all. A low ride height would introduce scraping underneath the car which can cause damage to parts, and add to that the discomfort in the ride for both the driver and passengers. Race springs will usually require the installation of stiffer shocks to complement the stiffer spring rates to maximize performance.

Shock Absorbers/Dampers

Shock absorbers were introduced to dampen the up and down oscillation of springs. The first shock absorber simply two arms connected by a bolt with a friction disk between them. Resistance was adjusted by tightening or loosening the bolt. Durability was a big issue and through time, shock absorbers have evolved into more sophisticated designs.

Contrary to a common misconception, shock absorbers do not support the weight of the vehicle but rather control the movement of the springs and the suspension. Shock absorbers control the movement by converting kinetic energy from the movement into thermal energy which is dissipated through the hydraulic fluid. The shock absorber is therefore basically an oil pump.

The shock absorber is therefore basically an oil pump which works on the principle of fluid displacement. A piston is attached to the end of the piston rod and works against hydraulic fluid in the pressure tube. As the suspension travels up and down, the hydraulic fluid is forced through tiny holes, called orifices, in the piston. However, these orifices let only a small amount of fluid through the piston. This slows down the piston, which in turn slows down spring and suspension movement. As a result of this, shock absorbers reduce bounce, roll or sway and brake dive and acceleration squat.

Shock absorbers work on the principle of fluid displacement on both the compression and extension cycle. A typical car or light truck will have more resistance during its extension cycle then its compression cycle. The compression cycle controls the motion of a vehicle’s unsprung weight, while extension controls the heavier sprung weight.

Gas Charged Shocks

The development of gas charged shock absorbers was a major advance in ride control technology, which solved many ride control problems which occurred due to an increasing number of vehicles using uni-body construction, shorter wheelbases and increased use of higher tire pressures.

The design of twin tube gas charged shock absorbers solves many of today’s ride control problems by adding a low pressure charge of nitrogen gas in the reserve tube. The pressure of the nitrogen in the reserve tube varies from 100 to 150 psi, depending on the amount of fluid in the reserve tube. The gas serves several important functions to improve the ride control characteristics of a shock.

The prime function of gas charging is to minimize aeration of the hydraulic fluid. The pressure of the nitrogen gas compresses air bubbles in the hydraulic fluid. This prevents the oil and air from mixing and creating foam. Foam affects performance because it can be compressed – fluid can not. With aeration reduced, the shock is able to react faster and more predictably, allowing for quicker response time and helping keep the tire firmly planted on the road surface.

Sport-tuned/Performance Shocks

These are essentially twin-tube gas-charged shock absorbers which have modified valves to accommodate more aggressive driving and provide better handling characteristics to the car by improving road holding, reducing bounce, roll, sway and dive. Sport shocks are a good companion to sport springs and gives a minor boost to the spring rates to optimize its performance.

Sport tuned shocks are available in either standalone or in a package with specifically designed springs to work together. The sport suspension kit is normally recommended to avoid the problems with equipment matching as they have been engineered and tested to work together.

Strut Bars

The strut bar is one of the most common modification which is done to a car which improves handling dramatically. Some factory performance tuned cars come with strut bars installed. And yet, not everybody knows its purpose. The purpose of the strut bar (strut tower bar) is to tie the two opposing strut together as a single unit.

This upgrade’s main purpose is to reduce chassis flex on hard cornering. Normally the strut towers flex on cornering, resulting in body flex and loss of traction, because as we all know there is no traction in the air. The strut bar is designed to keep the struts from flexing by distributing the amount of force applied on one strut tower when taking a corner to both towers. This helps keep the tires in the desired position on the road, thus improving traction, exit speed and laptimes on the track.

Strut Bars

The strut bar is one of the most common modifications done to a car which improves handling dramatically. Some factory performance tuned cars come with strut bars installed. And yet, not everybody knows its purpose. The purpose of the strut bar (strut tower bar) is to tie the two opposing strut together as a single unit.

This upgrade’s main purpose is to reduce chassis flex on hard cornering. Normally the strut towers flex on cornering, resulting in body flex and loss of traction, because as we all know there is no traction in the air. The strut bar is designed to keep the struts from flexing by distributing the amount of force applied on one strut tower when taking a corner to both towers. This helps keep the tires in the desired position on the road, thus improving traction, exit speed and laptimes on the track.

Rear strut bars are designed similarly to work like front strut bars by tying the two rear struts together. This upgrade improves overall chassis stiffness, minimizes understeer due to less chassis flex, and improves stability when braking into corners as it helps maintain balance for the vehicle.

Strut bars are indeed a very good addition to spring and shock upgrades as these combined with wider wheels and tires add extra stress to the chassis. Strut bars not only contribute to the sub-frame of the vehicle but also add to the overall chassis stiffness. And with a better performing chassis, steering response improvement can be achieved as well.

On most if not all applications, installation can be done in minutes and some particular aftermarket models look shiny and cool. At least now you know there’s more to its being shiny and cool. And looks don’t exactly have anything to do with performance. When choosing a strut bar, choose the most rigid design as possible to make the most out of the money you are spending.

Sway Bars/Anti-roll Bars

Sway bars tie the lower suspension components together across the front or back. These are also otherwise known as stabilizer bars which are connected to stabilizer links. This affects the handling of the car on the lower end of the suspension. They can either affect a car’s oversteer and understeer.

The task of the sway bar is distribute the energy made by the turn from one side to the other to balance out the car, keeping it flat instead of letting it lean to one side. But it does not necessarily mean that the car will not lean at all, it will only minimize the lean. Most modern cars come with sway bars standard for the front and some even on the rear. But these standard sway bars can be upgraded to thicker diameter ones which further minimize the lean.

Now that you know the basics of suspension tuning, you now know that there is more to making your car look better with changing to lowering springs and adding strut bars. You must have learned by now that cutting springs is definitely a no-no in any application whatsoever. It is a common unsafe practice done by people who try to be engineers of their own practice. Having an uneven ride height (in most common cases excessively higher rear suspension) is also not recommended as it adversely affects the cars balance and handling. But in some applications, drag racing specifically, these give minor performance and traction improvements. But take note that it is unsafe to drive with this setup on the street.

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Performance modifications, what really does work and what does not work? From one conflicting statement to the other, you as a newbie are indeed getting confused at different parts you’ve been hearing here and there. Performance modifications need not be complicated. Let us first define what basic performance modifications are, these are the basic bolt-on parts you install to increase performance. Contrary to popular belief, these will not make your car radically fast nor add a huge amount of horsepower. They will give you some gains but don’t expect too much.

Basic engine performance modifications consist of intake system, exhaust systems, exhaust manifold (headers). Being basic, these are relatively easy to install and should not be hard to find as well.

Intake Upgrades

Since the engine combusts a mixture of air and fuel, better airflow means increased performance. Air filters are made with different kinds of materials, each with their own filtration properties. Examples of materials used for filters are paper, cotton gauze, foam, and steel mesh. Paper is normally used for original equipment applications as these are economical to produce and deliver adequate filtration for normal road use. For performance applications, paper has been tested to be restrictive and robs the engine of its hidden potential. Hence the introduction of performance air filters. There are two kinds of performance filters, the drop-in and the open-type. And with the development of performance kits derived from racing application, cold-air intake systems were evolved.

Drop-in filter

A drop-in filter is a direct replacement filter which you simply install inside the original air intake box. These have less restrictive materials which allow more air to flow through. The advantage of this type of filter is, you get to keep your original air intake box which was designed to resonate air intake noise.

Open-type filter

An open-type filter was designed to replace the air intake box, thereby directing more flow to the engine. Like the performance drop-in filter, the open-type uses less restrictive materials to allow better airflow. An adapter is required to install this type of filter, but is usually provided. The advantage is unrestricted flow as air is directly fed into the air filter. The downside of the open-type filter is that it produces more noise because of the absence of the intake box.

Intake System Types

Short-ram system

A short-ram intake uses a short tube (aluminum, stainless, or plastic) to connect the intake manifold to the filter. This usually runs until before the headlight. The advantage of this is because the intake tube is relatively short thus air is sucked in fast towards the intake manifold, downside is it can also suck in the hot air inside the engine bay due to location of the filter. This is an all-weather setup.

Cold air intake system

A cold air intake system employs an open-type filter. Unlike the basic open-type filter, specially designed piping is used to direct airflow to the engine. The filter is usually located away from the engine compartment to reduce air temperature. Some use special heat retardant materials for the pipes to improve performance. Since it is about increasing airflow, and cold air gives better performance, true performance enthusiasts go for this type of setup. The setup unfortunately is restricted to dry weather due to the risks of the engine sucking in water.

Ram-air intake system

The Ram-air intake system employs an open-type setup meaning there is no filter being used. Unlike the cold air setup, this setup gets its air directly from a hole straight to the throttle body. No filter means no restriction and the air is forced into the intake system as the car speeds up as if it were being rammed-in, hence the name. Usually the headlight is replaced with a specially designed funnel to direct the air to the intake pipe; some use the front grill, while some use the bumper. Setup styles may vary but the principle is the same. This setup is to be used only for competition purposes and not for street use especially when the headlight is replaced with a ram air system as it is illegal to run only with one working headlight. It is also unsafe for the engine to run on a ram air setup on a daily basis due to the absence of a filter as foreign objects might go inside the engine and damage it.

Exhaust System

An exhaust system is the set of tubes and chambers that remove exhaust gases from the engine, reduce noise of exhaust pulses, and direct poisonous gases away from the passenger compartment. It is basically composed of pipes, a primary silencer and a muffler. Without an exhaust system, the engine would make a very unpleasant sound, as well as increase the risk of poisonous exhaust gases entering the passenger compartment. It is also illegal to drive a vehicle without an exhaust. Original equipment exhaust systems were designed to produce less noise and meet emissions requirements; they are usually designed restrictively thereby robbing the engine of potential power. Aftermarket exhaust system designs vary on application, two in particular, street legal and racing. The main objective of a street performance exhaust system is to free up the backpressure while still maintaining a tolerable sound pressure level to meet legal noise and emission regulations. A racing exhaust system is designed for maximum performance without having to consider legal regulations on noise and emissions.

Exhaust System Types

Street Performance System

As more air is fed through the engine by means of an intake system upgrade, that air has to go out faster for the engine to produce more power. A modern street performance system basically has four things to do: remove the exhaust gases from the engine as efficiently as possible, reduce the noise of the exhaust pulses to acceptable levels, reduce harmful emissions in the gases, and direct the poisonous gases away from the passenger compartment. These are also commonly referred to as cat-back systems as they bolt-on to the catalytic converter. Street systems come in two muffler configurations, they are either chambered or free flow. There are two kinds of street systems, the chambered and free-flow, referring to the muffler design. Normally, free-flow design mufflers will give a slightly bigger gain than chambered mufflers with the expense of reduced comfort levels due to increased noise. These systems are designed to meet strict legal regulations on emissions and noise levels.

Racing System

Racing exhaust systems have only one goal, increase performance. Modern racing exhaust system utilize different metals like stainless steel, and titanium to produce the most power at the lightest possible weight and offer increased durability. Most racing systems utilize straight pipe designs because of the consideration of the racecar not having a gas tank underneath to block the way of the exhaust pipe and risk a fire. As noise is not a factor in racing, these systems utilize free-flow muffler designs for lighter weight and increased flow rates. Emissions requirements are also not applicable in racing that is why these systems connect directly to the exhaust manifold. These systems are strictly for use on the race track as they are not guaranteed to meet emissions and noise regulations.

Hybrid System

These are exhaust systems which combine both Street Performance and Racing System designs. They are primarily street systems with free-flow design racing mufflers which are equipped with silencers for street use. These silencers can be removed for use on the race track or engine tuning for the engine to realize higher potential.

Exhaust Manifold

The exhaust manifold or exhaust header as it is commonly referred to is the primary outlet of engine exhaust gases. It is a very critical performance upgrade as a wrong manifold design will have detrimental effects on engine performance. For inline 4-cylinder engines, there are two configurations which are 4 into 1 and 4-2-1. For inline 6-cylinder engines, 6-2-1, 6-3-1. While there are different metals used to make exhaust manifolds like mild steel, stainless steel, titanium and Inconel, mild steel and stainless steel is commonly used in aftermarket systems. Titanium is usually used in custom manifolds, they are very much expensive compared to mild and stainless steel. Inconel uses high strength austenitic nickel-chromium-iron alloys that have exceptional anti-corrosion and heat-resistance properties. Inconel has been used by Formula One and Champ Car exhaust systems for years and is even more expensive.

A good exhaust manifold has to be mandrel bent. Custom made crush bent manifolds won’t do much, and will in most cases decrease engine performance and increase fuel consumption abruptly. For most street car applications, recommended material for headers are ceramic coated or aluminized mild steel to stainless steel. Ceramic coating and wrapping stainless steel headers helps maintain high exhaust velocity and increase scavenging. Another advantage is to protect the car and the driver from fatiguing high temperatures caused by radiated heat from the manifold.

The above modifications are just basic modifications to improve the flow of air in and out of your engine. After installing these modifications, expect your throttle response to improve as well as overall engine performance. Fuel consumption will still depend on how you drive the car. Never expect to consume less fuel with these modifications as they were never designed to conserve fuel. As you increase air, you also need to increase fuel to make more power. As for how much power you gain, it is best to leave it to a dynamometer to tell you that. Have a before and after dyno test to find out how much power you gained from your modifications rather than guess with your butt.

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How do you define Horsepower? A good way to effectively explain this word is to give a glimpse of history back to the time of the British inventor James Watt (1736-1819). It was Watt who coined the term “horsepower,” to increase sales of his improved steam engines. He had previously agreed to take royalties of one third of the savings in coal from the older Newcomen steam engines. This royalty scheme did not work with customers who did not have existing steam engines but used horses instead. Watt observed that a horse could turn a mill wheel 144 times in an hour, or about 2.4 per minute. Watt calculated that the horse pulled with a force of 180 pounds (just assuming that the measurements of mass were equivalent to measurements of force in pounds-force, which were not well-defined units at the time). So:

James Watt and Matthew Boulton later standardized the figure to 33,000 ft. – lbs. / minute, the figure we use today. Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 ft. – lbs. / minute. Put another way, if you were to lift 33,000 foot-pounds over a period of one minute, you would have used up one horsepower. Engine horsepower is the relationship between known engine torque at specific engine speed divided by Watt’s equivalent unit of one horsepower. Simplified, the equation is:

TYPES OF MEASUREMENT:

INDICATED or GROSS HORSEPOWER

This is the old process that American manufacturers used as a guide for rating their cars. It was in place prior to 1972. SAE gross horsepower also measured at the flywheel, but with no accessories to bog it down. This is the bare engine with nothing but the absolute essentials attached to it; little more than a carb, fuel pump, oil pump, and water pump. SAE J245 and SAE1995 define this measurement.

SAE NET HORSEPOWER

In 1972, American manufacturers phased in SAE net horsepower. This is the standard on which current American ratings are based. This rating is measured at the flywheel, on an engine dyno, but the engine is tested with all accessories and standard intake and exhaust system. Both SAE net and SAE gross horsepower test procedures are documented in Society of Automotive Engineers standard J1349. Because SAE net is so common, this is the standard we will use to compare all others. This is what most automotive manufacturers publish as SAE net horsepower. Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines show a variance of anywhere from 40 to 150 horsepower.

BRAKE HORSEPOWER (BHP)

Prior to electronic bench testing, horsepower was quantified as the amount of resistance against flywheel brake. Although the method is no longer used, the term remains an industry standard. Often road test magazines will measure as “bhp”. This is just another way to talk about SAE net horsepower.

DIN HORSEPOWER

This is a standard, DIN 70020, for measuring horsepower that very closely matches SAE net. The conditions of the test vary slightly, but the required equipment on the engine and the point of measurement (flywheel) remains the same. Because the test conditions are similar, it is safe to divide DIN horsepower by 1.0138697 (metric horsepower) to arrive at SAE net. This value is so close to equal that for all but the most technical purposes DIN and SAE net are interchangeable. However, be aware that DIN “horsepower” is often expressed in metric (Pferdestärke/ps) rather than mechanical horsepower.

SAE CERTIFIED HORSEPOWER

In 2005, the Society of Automotive Engineers introduced a new test procedure (J2723) for engine horsepower and torque. The procedure eliminates some of the areas of flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as “SAE-certified”. Many manufacturers began switching to the new rating immediately, often with surprising results.

ADVERTISED HORSEPOWER

This rating is measured at the flywheel. The engine is tested on an engine dynamometer or engine dyno by the manufacturers based on SAE net standards. Those horsepower figures presented in advertising materials are often based on engine tests under ideal environment to be able to advertise the best results. These figures are merely a baseline figure taken from the most powerful engine tested or an average of the engines tested.

EFFECTIVE HORSEPOWER

In automobiles, effective horsepower is often referred to as wheel horsepower. Most automotive dynamometers measure wheel horsepower and then apply a conversion factor to calculate net or brake horsepower at the engine. Wheel horsepower will often be 5-15% lower than the bhp ratings due to a loss through the drivetrain.

The most common chassis dyno, the inertial dynamometer (popularized by DynoJet), measures the horsepower as delivered to the wheels – whether front (fwhp), rear (rwhp) or both (4whp). This kind of machine measures the horsepower produced by the engine and computes for the torque from the engine speed. In other chassis dynos like Bosch, Dynopack, etc., the torque output measurement is rather based on the relationship of horsepower and the wheel speed. That is why the torque figures in the first, second and third gears are completely different.

SURPRISE HORSEPOWER

Factory ratings are all well and good. But manufacturers, measure horsepower at the flywheel (test on an engine dyno in a controlled environment). Ironically many enthusiasts measure horsepower at the wheels (test on a chassis dyno), mainly because they are not interested in ripping the engine out of their car to have it tested on an engine dyno. And, to the surprise of many, the horsepower numbers presented in advertising and brochures aren’t always accurate.

The dynamometer is a measuring machine, in order to make a proper comparison, it should be made using the same type of measuring machine.

Well, without taking into consideration the circumstances under which it is measured, testing wheel horsepower (whp) makes it difficult to convert from what the dyno says to what the manufacturer says. All that equipment between the engine and the wheels – the transmission, driveshaft, differential, and axles – introduce friction and inertial losses summarized as “power train loss” or “parasitic losses”. The efficiency of the driveline can greatly affect the amount of the power train loss. Some may incur more power loss, some may incur less. It really depends on the design of the drivetrain and the weight of the parts. That is why there is no real formula for converting wheel horsepower to engine horsepower (contrary to popular belief).

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