What Does a Blow Off Valve Do For a Turbo Charger?

What is a blow off valve and what good does it to the turbo charger?

A blow off valve releases excess pressure produced by a turbo charger. The turbo charger releases the pressure when you shift into different gears, or when you step on the acceleration pedal and let go off it. The reason why a blow off valve is installed into a turbo charged engine is to prevent compressor surge and strain placed on the engine. Most people replace the stock blow off valve with an aftermarket blow off valve, so when the pressure is released into the atmosphere, it creates a 'pshhh' noise, that all boy racers love!