What does a BOV do?

[smithers_0990]

I don't know for sure. Can you help?

 

[derrick1623]

ill try...i believe that a blow-off valve releases the extra pressure when the engine is under boost.

someone PLEASE correct if im wrong!

 

[Stou]

The BOV release the pressure when the throttle is release to protect the turbo for a pressure back and to keep the turbo spoolin.

Ref: About blow off valve

 

[Traveler]

The BOV is to save the compressor on the turbo. If you are under boost and you chop the throttle, momentary pressure on an 8 psi system can spike over 30 between the compressor and the throttle body. This puts a huge backwards load on the compressor vanes and flexes them slightly. Do this a few times and you can break a compressor wheel. Also, the pressure doesn't just spike it pulses at the resonant frequency of your intake between the throttle body and the turbo. The other thing that the pressure surge will do is act like applying the brakes on the turbo like Stou said. If the pressure spikes too high you can actually stick the throttle blade shut in the throttle body as well as break the compressor.

 

[big_ben]

Precisely.