Originally posted by Bob H:
The blowoff valve is a safety valve that is installed in the intake stream after the turbo compressor to protect your engine in the case that the wastegate malfunctions, or someone bumps your boost controller and accidentally sets your boost to 80psi instead of 8psi or something. It is a backup device for protecting your engine.
Nope. The blowoff valve is a safety valve that is installed in the intake stream after the turbo compressor to protect your
turbo from the air piling up against the closed throttle plate during shifts while you let off the throttle, or as you come off the throttle at any other moment while the intake was under boost. Phenomenon called compressor surge.
The BOV is not there to protect the engine against wastegate malfunction or people tinkering with your setup. Although it would effectively bleed excess pressure to a certain extent, that's not it's intent.
