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By The Telegraph Online
  • Published 4.07.09

The rear diffuser controls airflow beneath a vehicle and helps in effective han-dling at high speeds

The rear diffuser is a section of a car’s underbody that plays a vital role in the car’s dynamics and overall performance. The rear diffuser consists of tunnels that allow the smooth and rapid flow of air underneath the car.

To gain maximum effect of the diffuser, the car has to be run as low to the ground as possible, as it causes the air trapped between the ground and the car to move quickly to the rear.

The diffuser causes negative pressure at the back of the car due to the volume of the air flowing into it, which is greater than the area it’s coming from. This puts the whole underside of the car under immense negative air pressure, creating a vacuum effect that helps to keep the car stuck to the ground, creating downforce.

This allows the car to handle effectively and corner in a much better way at high speeds. Rear diffusers can be seen on a range of four-wheelers — from sports cars such as the Lotus Elise and the Ferrari F430 to Formula One cars like Brawn GP’s BGP001 and the McLaren MP4-24.