It’s called tuning, modding, or modifying. You either tune or modify your vehicle for looks, for going faster or commonly, for both. The word ‘tuning’ has different meaning for different crowds, and almost always you get a image of a young urban kid with oversized shirt, baggy jeans, and a sideways turned cap driving a Honda Civic. Yes, there is that type of crowd. But tuning means much more than that. From simply accessorizing your car to getting every drop of performance out of your machine, ‘tuning’ is a broad term that covers a very wide automotive spectrum. If you have a boring sedan or a sports coupe with tons of performance potential, you can make it look top notch and perform like a supercar.
Think of this as the beginner’s guide to modifying your ride. Please check with your local and State law enforcement agencies. Most of the items that are covered here maybe illegal in some areas. As our slogan says, this is the first step to a great ride, enjoy!
Lowering you car
You might want to lower the car for couple of reasons. Either you want it to look good, closing the unsightly gap between the tire and the fender, and/or you want it for cornering performance. This step is probably one of the first modification done to the car because it has the most visual impact on your vehicle, other than paint and body kit. You can use lowering springs (mild and most common), racing coil-over-springs (coilovers), or airbags (for shows and cruising, not performance oriented). Remember if you use lowering springs, your shocks and/or struts will work extra hard and wear out faster, so you should invest in heavier duty shocks/struts made for performance application. When using springs or coilovers to lower the vehicle, you also lower the center of gravity. Because you are using stiffer springs, you reduce the vehicle’s body roll (side to side rocking motion), therefore giving you maximum enjoyment on twisty roads, and you will often hear “it handles like it’s on rails” from enthusiasts.
Cold-Air Intake
Your engine is nothing more than a fancy air pump. How the air moves in and out of the engine is the measure of power and efficiency. Cold-Air Intake (CAI), or ‘intake’ as it is often called, is the first step to making your engine breathe better. The manufacturers often make this part of the engine restrictive, because of noise issues. The less restriction the intake has, the more noise you will hear- sort of like a loud sucking sound. But most performance car will have a really good performing intake from factory and may not be necessary.
Headers
This is part two of the whole ‘engine breathing apparatus’. Exhaust manifold, the correct term for this system, is the part where the exhaust gases are collected directly from the engine and passed to the exhaust piping underneath the vehicle. Often the manufacturers will use a cast piece that is a little restrictive, mainly for noise issues but also for emissions controls. Because of the casting process, the exhaust manifold is a bit rough and has a lot of imperfections, not to mention how heavy these plumbing pieces are. With aftermarket headers, you not only increase the airflow but save weight and it is more attractive to look at.
High Flow Cats (Catalytic Converters)
Stock catalytic converters are often restrictive, sucking up precious power and fuel economy. But it’s a necessary evil, because you don’t want to be irresponsible to the environment. You can replace the stock units with the high flow ones, but the high flow units generally do not clean the exhaust gases as well as the stock ones.
Cat-back (Catalytic Converter and back) Exhaust System
The most power is hidden here. The stock units are often cheaply produced with sharp angles and crushed bends. Remember the sole mission of performance tuning is having the engine breathe better, which means a proper exiting of the spent gases. Having the exhaust gases flow out more efficiently means more power, not to mention deeper, louder sound. Be careful here, because improper sizing of the exhaust piping will make obscene levels of noise, and do almost next to nothing for your performance. The cat-back exhaust includes the piping, but also the muffler and the tip.
Forced Induction
Supercharging, turbocharging, and/or nitrous oxide systems (NOS or laughing gas) artificially pressurize the incoming air into the engine. Once again, it’s all about the breathing thing, the more air in the engine the more power. Superchargers (aka blower) use some of the power from the engine itself to pressurize the air. Superchargers are used in bigger engines mostly. Turbochargers are a form of supercharging, but they use the exhaust gas in the exhaust manifold to spin the turbine (turbo) to pressurize the air. The turbos are more efficient than the superchargers, but require more plumbing (piping). Nitrous oxide systems use the NO2 gas stored in bottles, and forcibly blow the oxygen rich air into the engine. Obviously because the nitrous gas is stored in a bottle, you constantly have to refill/replace. Also it is the least expensive way to get forced induction. In any form of forced induction it is generally a good idea to build up your engine with stronger parts for reliability and longevity.
Front Lip Spoiler
Sometimes it’s referred as ‘front lip kit’, ‘air dam’, or ‘front splitter’. They serve one function: aerodynamics. It extends the front bumper down a few inches. This means the air flows around and over the car, instead of going underneath the bumper creating ‘lift’ at high speeds. When you get lift in the front at high speeds, the front wheels lose some traction and steering becomes less responsive and squirrely.
Side Skirts
These are just extension of the side sills of the vehicle, making the car look lower to the ground. Similar in function to the front lip spoiler, but the side skirts do not help with reducing lift. The skirts are made to have the airstream flow around the car a little cleaner, reducing drag. Having less drag is important in aerodynamics. Because the vehicle is slipperier to air, it means less wind noise and more top speed.
Rear Diffuser
Same purpose as the front lip spoiler and side skirts. It’s meant to calm the turbulence within the airflow around the vehicle, creating a more stable ride at high speeds.
Rear Spoiler
We’ve covered lift, drag, and turbulence. Now it’s time to talk about downforce. Unless your car’s bottom edge is touching the ground, there will be some space that the air can flow under the car. The faster you travel, the more air will want to get underneath, hence the lift. Along with the front lip spoiler or splitter, the rear spoiler will produce downforce to keep the car planted on the pavement.
Body Kit
When a vendor offers the above four items as a matching set, it is called a ‘body kit’. In the old days, the body kits were also called the ‘ground effects’. Another popular name, especially among the automotive companies, is ‘aero kit’ or ‘aero package’.
Strut Tower Brace
Some high performance vehicles already are equipped with them. The engine bay and trunk/cargo/hatch area are just vast open cavities. It also happens that the struts/shocks are mounted in these area, creating stress points in the chassis. When you take hard corners at speeds, these stress points flex as the cornering/speed load increases. When the chassis flexes, the suspension parts do not work as efficiently as they are designed to be. The braces go on top of the strut/shock mounts, and strengthen the chassis. They do not eliminate chassis flexing totally, but reduce enough of it so that your suspension can do its job.
Sway Bar
These work much like the strut tower brace, the bottom of the suspension are not supported as well as the top side. So using sway bars (anti-roll bar or anti-sway bar) brace the bottom side of the suspension parts to reduce flexing of the non-compressing suspension parts. These also work to keep the suspension level, reducing body roll of the car while cornering aggressively. Be careful though, going too stiff, or not matching the front and rear rates to the rest of the setup, can cause your car to have a poor ride and undesirable handling characteristics.
Wheel Size and Offset
Not only big wheels look cool, but they actually have a purpose. The less sidewall rubber gives you less flexing of the tires. That increases the overall sharpness of the handling competency of your vehicle. You will also feel more of the road, giving you more input, so you can make corrections you need to. The offsets of the wheels are mainly dependent on which wheels drive the vehicle. For example, front-wheel-drive cars will have high offset and rear wheel drives will have lower offset. The most obvious way to tell this is the face (or spokes) of the wheel are flush with the tire or sunken in, creating a lip.
-KF