Well I gotta say that you guys have no clue what you're talking about. The BPV does NOT, WILL NOT, CAN NOT, "add" any power, boost, or anything else for that matter. You can completely REMOVE the BPV, install a plate over the hole and the car will have the SAME power. I've yet to figure out how/why ANYONE with half a clue on turbocharger system function could make this mistake/claim.
The BPV (ANY brand/design) can only HURT performance, it can NOT increase ANY aspect of "performance".
The ONLY "valid" reason for changing out the OEM BPV is that is is physically broken and leaking. My definition of "valid" is for power/performace, NOT for additional or different SOUNDS when it relieves the manifold pressure trapped when the throttle plate snaps closed.
The ONLY reason a turbo setup employs a BPV is to reduce the stress on the turbocharger shaft and thrust bearings from the sudden slowing when the throttle is closed under boost, and the resulting lag as the turbo must "regain" the turbine speed. If the manifold pressure isn't released, it the pressure puts a huge load on the compressor wheel outlet side and slows the turbine drastically. The BPV is installed to allow this trapped pressure to vent back into the main air inlet to keep it "in" the system. In older systems not using MAF sensors for misture control, a BOV can be used to vent the pressure overboard.
The OEM BPV reacts faster than ANY aftermarket BPV, so the ONLY result you can possibly get from replacing a properly functioning OEM BPV is more noise and LESS performance.
