I went to thunder valley last year and had traction problems. I only ran 12 psi because I had to drive the car 2 hours home and didn't want to break anything. I ran a 12.7 I think at 117 mph against CatDaddy who ran a 12.2 at only 115 mph and I think he was running fairly high boost. I think maybe 20 but you would have to ask him. He had the auto and I had the 5 speed. I couldn't get it to hook up until half way down the 1/4. I wasn't problably running 40 or 50 at the half way until the car finally took hold. Just some info for what it is worth. Traction is a big problem for me atleast but anything above 100 mph or so it hooks up and then the show is on. .......