How would it slow me down? I figured a smaller pulley would increase the speed of the belt rotation. Therefore the faster the rotation the more boost you make. My supercharger is capable of 10 psi and only pegging 7 psi right now. With some race gas (100 octane), custom cold air induction, and smaller pulley (i thought) could possibly peg the 10 psi. Someone help me out. I need to know by Wednesday.