The turbo wastegate controls how much boost your turbo makes. Left unchecked, the turbo will create exponentially higher boost numbers as the engine RPM goes up. The wastegate has a vacuum port that attaches to manifold vacuum and it opens at a set point. This unit limits our turbo to about 7 pounds of boost. The kits that carry the one-year warranty will be sold with a pre-set 6 pounds of boost. If that isn't enough for you, you can get optional springs to increase boost, but you void 505's warranty.