Originally Posted by TopgunZ

This sound is not harming anything. It is from the BOV oscillating and the sound is reverbing into the pipe and out of the supercharger inlet. The reason it is so audible is because my Gen 1 kits all came with the KN filter and it muffled this sound where as the ACE kit comes with the velocity stack and pre filter which does not do as good of a job at dampening these sound waves.

It might have something to do with the harmonics of the pipe layout and it is being directed into the inlet differently.

The physics behind this are no different. The same BOV is seeing the same vacuum as the Gen 1 kit. Its always there, just more audible now.

When I tested the Precision turbo 50mm it was MUCH quiter than the Tial QRJ so I am surprised to hear that it is still that audible. In fact, Tony, the owner of the RnD Z, switched back to the QRJ from that PT because he thought the PT was too quiet and wanted to hear more BOV noises.

I also just picked up the new Turbosmart 50mm stealth and am putting that on today to see how this reacts to try to find a solution to anyone who doesn't prefer the noise.