Spoilers and other aerodynamic devices such as wings and diffusers increase the performance of a vehicle. While some reduce the air drag on the car, increasing top speed and reducing fuel consumption, others are designed to increase grip. In this article we will cover some of them and what they do.
Note that all vehicles go through extensive air drag testing. However, more aerodynamically advanced cars are also more expensive.
Why is Air Drag important?
Once cruising at a given speed, the engine works hard to keep the vehicle moving against air resistance. Generally, maintaining speed through the forces of air pressure uses five times more power than it does to accelerate.
To experiment with air resistance yourself, stick your hand out the window of a car with a horizontal palm. Now turn your wrist so your palm is facing forwards. The car is like your hand: we want to make it as flat as possible to cut through the wind more easily.
What Does a Front Spoiler Do?
Front spoilers are usually fitted underneath the front bumper bar, or incorporated into it. By keeping air from flowing underneath the vehicle, it decreases air pressure under the car and increases downforce.
What Does a Front Splitter Do?
Front splitters are an addition to a front spoiler (or installed separately) and act as a wing which helps further increase downforce. Some cars that do not have a complete front spoiler often use front splitters instead - these are attached directly from the bottom edge at the front of the vehicle.
What Are Air Diffusers?
Air diffusers work differently from the two spoilers mentioned above, instead of sucking up air into channels under the car. This speeds up the process of removing air from underneath the car. This decreases air pressure, creating more downforce, and helps eliminate air turbulence at the rear of the car. You’ll most often see air diffusers underneath the rear bumpers of high-performance vehicles.
What Are Vortex Generators?
Vortex generators are fins, or small ridges placed on the car to optimize aerodynamics. Vortex generators not only deflect air and reduce drag, but also direct airflow to increase downforce.
What Are Side Skirts?
Like diffusers, side skirts help underbody aerodynamics. They do so by creating ‘dams’ for the air to flow and lowering the vehicle to the ground. Side skirts, as the name depicts, are fitted to the sides of the car under the main body between the front and rear wheels.
What Are Rear Spoilers?
Rear spoilers are the most common aerodynamic aid that you’ll find. Most people like them because of the aesthetic and care little about their purpose. This is why many spoilers are designed for looks rather than function. If you are going to install a spoiler for more downforce, check the manufacturer’s performance details.
A rear spoiler is a metal or fiberglass panel that usually sits on top of the boot. As the name suggests, a rear spoiler ‘spoils’ the airflow by directing it upwards, thus pushing the car to the floor.
What is a Rear Wing?
Rear wings also help reduce lift, but unlike a spoiler, they also increase air drag, especially at higher speeds. Still, the increased grip results in higher performance in medium to low speeds.