Form vs function: Are bodykits really necessary?

Bodykits have long been a mainstay in the automotive aftermarket scene. They come in a wide and varied range, from humble side skirts and bumper lips to full-blown widebody kits that make even the meekest vehicle look aggressive.

But what purpose do they serve, exactly? Is it function or form that drives builders to make these bodykits?

In truth, all bodykits do function, but while some function to the advantage of a car’s capabilities, the vast majority hinder the car’s performance, either through a fluid property called drag or simply by adding unnecessary weight.

So what makes a bodykit functional? The answer to that question is that it depends on several different reasons, but the biggest would be the following:

• Aerodynamic/ Vehicular design

• Vehicle speed

• Vehicle purposes

• All or some of the above

So when do each of them apply?

Aerodynamic/ Vehicular Design

The first consideration is aerodynamic and vehicular design. Usually, a functional bodykit serves to channel air to specific locations, but the main goal is to change the drag coefficient of a vehicle.

If a bodykit makes a car more slippery (less drag), then the bodykit must drive the vehicle to move through the air in as small a hole as possible. When is this required? Generally, a more slippery car consumes less fuel – if air can move effortlessly around the vehicle, then the car experiences less air resistance, thereby requiring less power to move forward. One way to do this is with the Kammback rear hatch design, found in many hybrids and EVs, like the Toyota Prius and the Ford Mustang Mach E.

Alternatively, it can also increase drag, significantly aiding a vehicle’s handling ability when used properly. Aerodynamic drag, when used in conjunction with proper suspension tuning, can be used in a property called downforce, a way to use air pressure – or the lack thereof, in some cases – to increase the force applied on the tires, which then translates to more tractional force between the tires and the road surface. Obvious applications of this are the huge front and rear spoilers commonly seen on Formula 1 cars and other open-wheel racing cars.

Naturally, such advanced aerodynamics are unnecessary in the typical hatchback or sedan. So having “aerodynamic” bodykits on, say, a regular sedan or hatchback will be less function and more form.

Vehicle Speed

Going back to the point about race cars needing functional bodykits for aerodynamics, the reason is that they run at extremely high speeds, and regular road cars do not. If you corner at over 150 kilometers per hour, it will make sense that you would need all the help you can get when tackling the corners of the Nurburgring, and the same applies to any road car that finds its way to the higher speeds experienced on the track. While the typical Toyota Yaris does not need a high-mount spoiler on the roads of Metro Manila, a Toyota Yaris-GR could very well need it for added traction on the track.

After all, you may have the fanciest bodykit on the fanciest car in Metro Manila, but it’s all only for show unless you show up at the track.

Vehicle purpose

And that brings us neatly to our last point about functional bodykits. They have to be designed with a purpose. And yes, a bodykit has a purpose, even a widebody kit.

Historically, widebody kits and flares have been used by race teams to increase mechanical grip on their race car by increasing the track width and tire width of a vehicle. In a properly-built widebody race car, if more of the weight sits lower down and within the track width of the vehicle, the center of gravity is lower than it would be, making the vehicle more stable at high speed. Being less prone to body roll also means that weight transfer is more controlled and usable in putting more force on the wheel with the most traction.

Naturally, race cars can’t just run with their wheels poking out of the fenders – for one, it’s not safe, and for another, it ruins the car's aerodynamics by creating turbulent air around the tires. Thus, the widebody was born.

So to answer the question: Do bodykits serve a function? In a word, yes. Yes, if they are used for their intended uses. Yes, if they are designed properly by aerodynamic engineers. Yes, if they are fitted to cars that require them. Still, looking cool may be a function in its own right, depending on how you define function.