I tested it once more:
-Screen material behind louvers yields 3/8" of negative vacuum under the car
Took it out to the autocross today, did pretty well. It was my first time on semi-slicks which made the car feel quite different. Just trying to forge ahead and do any more low-cost aero. tricks to go faster then look at modifying the engine and trans.
One thing I also noticed looking at the front of my Audi RS4 (mine's black, I borrowed this picture below), there's these short deflectors almost like mudflaps on the front to counter the drag of the front tires. Gives me an idea...
