[knucklehead]

Originally Posted by jhnmdahl

I stand by my original post. The vacuum effect of expanding air in the diffuser region pulling the car down is a myth, although the slight vacuum behind the car does help scavenge the relatively higher velocity air from under the car, where the downforce is created (under the body of the car, not in the diffuser region). Check out:

Diffuser (automotive - Wikipedia, the free encyclopedia)

Diffuser

Secrets of Underbody Tunnels, Rear Diffusers and Venturis | Symscape

for example.

John

Where did your original post go?