Downforce - Body

Body

The rounded and tapered shape of the top of the car is designed to slice through the air and minimize wind resistance. Detailed pieces of bodywork on top of the car can be added to allow a smooth flow of air to reach the downforce-creating elements (i.e., wings or spoilers, and underbody tunnels).

The overall shape of a street car resembles an airplane wing with air flowing over it faster than the air flows under it causing a difference in air pressure. Almost all street cars have aerodynamic lift as a result of this shape. There are many techniques that are used to counterbalance a street car. Looking at the profile of most street cars, the front bumper has the lowest ground clearance followed by the section between the front and rear tires, and followed yet by a rear bumper usually with the highest clearance. Using this method, the air flowing under the front bumper will be constricted to a lower cross sectional area, and thus achieve a lower pressure. Additional downforce comes from the rake (or angle) of the vehicles' body, which directs the underside air up and creates a downward force, and increases the pressure on top of the car because the air flow direction comes closer to perpendicular to the surface. Volume does not affect the air pressure because it is not an enclosed volume, despite the common misconception. Race cars will exemplify this effect by adding a rear diffuser to accelerate air under the car in front of the diffuser, and raise the air pressure behind it to lessen the car's wake. Other aerodynamic components can be found on the underside to improve downforce and/or reduce drag include a splitter and a diffuser and vortex generators.