What does a Blow-Off Valve do?
A blow-off valve (BOV), also referred to as a compressor bypass valve, is a valve which opens and closes depending on the status/position of your throttle plate and turbocharger. It is intended to increase turbocharger life by helping to eliminate compressor surge/back spin and increase performance by allowing the turbo to spin freely between shifts. To understand how a BOV works, you have to first understand that a turbocharger’s job, described in simple terms, is basically to compress air. It then sends this compressed air to your engine for increased performance. But when you think of what happens during gear changes (when you lift your foot off the gas) and the turbo is spitting out huge amounts of air but your engine is not taking in (hardly) any air the BOV’s job becomes apparent. Just like anything that’s compressed into a smaller volume than it usually takes up, it wants to expand. So all the air from the turbo keeps pushing toward the (closed) throttle plate and begins to buil
