Blow off valves "mythbusted", also, BOV on a NA car...

[DivideBYZero]

That doesn't show throttle response though, which is what Shawn was complaining about.

It does however show that "an old valve with leaking valve seals" sucks. That should be common sense.

It also shows that if a factory valve is rated at 10 psi, it will vent any boost you generate above about 10psi by remaping the ECU.

A BOV isn't controled by the ECU, though and a BOV will not vent at a given psi (unless it is just failing to seal). Boost is controlled by the ECU opening the wastegate. All a BOV does is vent excess boost upon closure of the throttle. It's entirely mechanical.

What it actually shows is a BOV designed for 15psi may leak at higher boost levels than factory, and you should think about replacing it with a valve with a higher rating.

 

[Apex]

I might be retarded, but I don't think those guys tested what the engineer actually said. He didn't say it gave more power. What he said was that saving some of the pressure rather than venting all of it reduced LAG because you start from maybe 3psi instead of 0. All their numbers showed was peak power, which has absolutely nothing to do with the throttle lag that guy talked about.

That's not retarded. That's exactly right.