I asked an indy car designer about autocross designes re areo. His answer was if you are driving 150 and above, this is a ll a big deal...at 50 MPH just make it look like a bananna and it will make downforce.

Then he continued; put in as many elements in that you can figure out how to build and have each elements bottom surface on the same bananna line. Make it light, make it strong and make it see airflow.

AW

I forgot to mention that most of the tunnel installs that I have seen on FSAE cars have very tight clearance between the tunnel and the ground. The issue that comes with this setup is that with chassis pitch the amount and center of the downforce moves HUGE. I found out about this about 10 years ago when I mounted a tunnel out the front of a fairly well ballanced racecar. On the very first run the car developed HUGE oversteer and outragious oversteer on the brakes. I moved the overhead 20 SF wing back on the second run about 12" and cured the transient oversteer but on the brakes the new found downforce still caused HUGE snap spins. That was the day I figured out that even simple "napkin engineered" tunnels made downforce even at 40 MPH Five years later every car had some version of tunnels at nationals.

AW