the blow off just doesn't react to the throttle being closed quickly enough.. I know thats what that is because when I first got my ghetto I didn't have a blow-off and it made that similar noise but more amplifyed. I don't know if it's the placement of it or what.. Bellbusa has the same exact blow-off I had but his is right at the wastegate and it reacts very quickly and sounds more like your conventional blow-off... My blow off had a kinda...che, che, che noise to it..