I went with the synapse diverter valve. Personally I did not notice a higher hiss sound as the air was being drawn through the intake.
However, when you have built up boost and let off the gas, thats when you hear the air being recirculated into the intake.
Diverter, recirculator, blow off, etc. They are all have the same job, releasing the pressurized intake system when off throttle. But the difference is whether or not it puts the air back into the intake, or if it just lets it go into the atmosphere. I have a V1 motor and it will die if I vent to atmosphere. The diverter makes a fun flutter sound when making low boost, and a whoosh sound when higher boost is being made.
As stated, you will hear more whoosh and flutter with any short ram intake. When I put my stock intake on for smog (cali life) I don't hear it.
Enjoy the new toy, and all the fun turbo noises that com with it!
THE SIMPLE & ESSENTIAL MOD FOR 30% QUICKER BOOST. By retaining the factory ECU control and recirculating the vented air, the GFB BOV is a purely performance oriented product that offers the following benefits:
From a terminology standpoint, it is a "diverter valve", as Michael stated. "Dump valve" is kinda a slang word, alternate to "blow off valve" (BOV).
They are all diverter valves, they "divert" the pressure coming from the turbo away from the intake manifold. From there it can either recirculate back into the intake ("DV") or they can dump to atmosphere (hence "dump valve" aka "BOV"). There are also hybrids which do both, usually allowing you to adjust the percentage going to the recirc and atmosphere (like 30/70 or 50/50, etc.).
Recirc, atmospheric, and hybrid are each a subset of the "Diverter Valve".