Rule Change Analysis ::: Diffusers

As previously mentioned, the 2009 rules changes were meant to be game changers, a technical shake up intent on leveling the playing field if only by clearing the board and making everyone start from a fresh sheet of paper. 

At its heart, one of the key tools the regulations employ is reducing the effect of aero wake on following cars - so that cars can travel closer with less loss of downforce... all of which should allow for more passing at the entry or exit of corners and overall tighter grids. And, by looking at the cars you can see the wildly increased front wings vastly out proportioning the scaled down rear wings. But, what you can't see are the diffusers - and that's where some of the real technical gains have clawed back performance gains from losses suffered by the new regulations.

Brawn GP have a cunning interpretation of the rules, one that allows for greater diffuser efficiency by employing more complex rear sections that actually incorporate suspension, floor, and rear crash structures to create  a double decker diffuser. And, because great minds think alike Toyota and Williams also debuted similar twin floor concepts. 

Diffusers Explained:

1.The key role of the diffuser on a modern racecar is to accelerate the flow of air under the car, creating an area of low pressure, thus increasing downforce. Meaning, the shaped piece of bodywork at the rear of the car draws the air out from under the car sucking it to the track, creating aerodynamic grip.

2.How's it work: the air passing under the wing has further to travel than the air passing over the top surface. This causes the air under the wing to accelerate, resulting in a drop in air pressure, this creates a difference in pressure between the upper and lower surfaces. This difference essentially means the wing is pushed down by the higer pressure above, generating what is known as downforce.

3. With this in mind, the role of the diffuser on a racing car is to speed the airflow up underneath the car, reducing its pressure, creating a greater difference in pressure between the upper and lower surfaces of the car. This means more downforce and aerodyamic grip, allowing the car to corner faster.

These rules are not unique to the so called "Double Decker" diffusers, they apply to all teams' interpretations of the regulations and have been in use since Lotus started the ground effects movement. But, given their greater efficiency are double decker diffusers the killer app for F1 2009? In a word, "NO". Were it that simple, Toyota would have considerably more than 26 points and Williams would be placed higher than 8th in the Constructors Standings.