If you are referring to a hissing noise, to be honest, it sounds pretty normal based on what we've seen and experienced with these pieces. If it is making a "hissing" noise and goes away as soon as you hit the gas, it is perfectly normal. The reason it makes noises like that is because the valve is electronically controlled and is metered by the ECU via a solenoid, not purely by a vacuum source; this causes some noises like what you're experiencing. As long as the three screws are tightened properly on our BOV and the o rings are still in place, you are good to go. The car made this noise before, but you would never hear it due to the fact that it would be venting to intake rather than atmosphere. Since the turbos on these cars are so small, they are known to vent even when not making boost.