If you are boosting, you may want to check out the ATP boost activated cut-out. It opens the valve when you hit boost. You could even set it to stay closed until a desired psi for cruising the street.


I plan on installing a few on some street turbo cars. While out of boost, or below 4psi the car will be quite, but once you are into it, it will be open downpipe.

Check out ATP's site for it.