Ever wondered why F1 cars are so fast? It’s not just the engines that are a few horses shy of 1000 bhp. Or the lightning-fast gear changes. Most of the speed is down to aerodynamics – how the cars stay glued to the road, no matter if they’re passing through a straight or a bend.
The huge front and rear wings create enormous amounts of downforce, and this increases with subtle additions in the chassis and bodywork. Couple this with the lightweight, and you get a machine that can reach 0-100kph in under 2 seconds, and go on to 300kph in the blink of the eye.
Production cars will have little of the wizardry of pure racing machines. But they can come close. A fully sorted cars body kit consists of parts that optimally control airflow around the car with the ultimate goal of maximizing downforce and reducing overall drag.
Downforce increases as does speed. So, the faster you go the more planted the car is on the road. This definitely helps in handling, since there’s more grip to the tires, and dares drivers to carry more speed into the bends. And since all parts are purpose-built, they make a bland car stand out. You’ll get noticed both in the car park or at the track.
Benefits of an Aftermarket Body Kit
Body kit parts improve aerodynamics or ‘ground effects’. The purpose is to redirect oncoming air over, under, and around the car to produce areas of slow-speed pressure above the car (or downforce), and high speed and low pressure under the car from front air dams and skirts, rear diffusers, and spoilers.
This puts more vertical pressure along the length of the vehicle and increases the grip from the tires, in effect sticking the car to the road. The benefit is that handling (less understeer and more stability) is also improved and only gets better as the car goes faster.
Individual parts are precision engineered for each vehicle. They will redirect the right amount of air acting on the vehicle, in the desired direction and speed. But it’s not only about speed, better grip, or improved handling that a body kit excels. It also makes the car look the part. Here though there are two choices, parts for show and parts for go, and they’ll be priced as such.
The former will add little or no actual performance boost, while the latter may not look exceptional, but serve their intended purpose well. The best will be a combination of both – those that turn heads and increase performance.
Splitters, Spoilers and More
A purpose car’s body kit will consist of a front spoiler, also called an air dam, a splitter, side skirts, a rear diffuser, and a rear spoiler or wing.
Splitters are installed along the bottom of the front bumper and sit parallel to the ground. They are tasked to increase downforce by ‘splitting’ incoming air. With more air over the car flowing at a slower speed, but higher pressure, the car is pressed downward. There’s little resistance from the fast-moving low-pressure air under the car.
Front spoilers are responsible for ‘spoiling’ the air hitting the car. They redirect the majority of that air to the left and right of the vehicle, in effect helping cornering stability. Used in combination with splitters in a front bumper lip, they further increase downforce acting on the car.
Side skirts continue where front splitters and spoilers end. They prevent air from encroaching on the sides and underneath the car. And like splitter and air dams (front spoilers), they’re more effective the closer they are to the ground.
Diffusers utilize the remaining low-pressure air under the car. To help with handling and balance, they are installed at the lower end of the rear bumper. The ‘diffuse’ the air equally so now differences in air pressure affect stability.
Lastly, there are rear spoilers and wings. Both terms are used interchangeably, though the differences are profound. Rear spoilers are natural extensions of the bodywork, designed to further increase downforce, by redirecting air above the car upwards. Wings are additions bolted onto the rear of the car.
They also counter lift at the rear axle and thrust the car downwards. Rarely you’ll find a production car with wings (the Subaru WRX STi is an exception), though most new cars will have subtle inclusions that figure as rear spoilers. Aftermarket wings come in all sizes and are some of the more eye-catching changes to the stock car.
The materials the car body kit parts are made of will affect overall performance if that’s your ultimate task, parts strength when faced with more air resistance at higher speeds, and of course, price. Three materials are most commonly used – fiberglass, polyurethane, and carbon fiber.
Fiberglass is cheap and easy to paint, but has low rigidity, meaning it can crack on impact. It also requires more attention during installation. A step up from fiberglass is polyurethane. Parts made from this material are slightly more expensive but have better flexibility. There’s less of a chance of damage when installing or chips and cracks during driving. The downsides are that polyurethane parts are heavy (compared to the other offerings) and are more difficult to paint.
However, the best results are from carbon fiber. Car body kits made of carbon fiber have the highest strength, the lowest weight, and arguably the best out-of-the-box looks that you wouldn’t want to spoil with an additional coating of paint. The added strength makes the carbon fiber body kit the preferred choice of serious tuners and car builders, and anyone looking for a combination of the best performance and visual allure.
All this comes at a cost though. Since everything needs to be carefully paired to get a balanced car, the cost of individual parts soon adds up. If you’re going the whole hog, additional body styling parts specified in carbon fiber, like hoods (with air inlets for better cooling) and roofs, will shave off more than a few pounds when weight is a concern.
What to Expect?
The more you spend, the more the parts will be engineered for better overall grip and handling. Packages are carefully chosen to suit the build and dimensions of your make and model. Polyurethane and fiberglass spoilers and wings are more geared toward the looks department than anything else, and you’ll want to combine matching body kits in moderation.
For anyone looking to modify a car they’ll use extensively on the track, then carbon fiber kits are your best bet. To get the best return on your investment, a modified car needs to pick up some serious speed before you feel the difference behind the wheel. Either way, no matter which materials or ‘ground effects’ parts you choose, you’ll have a unique car that can also be driven hard.