Thread: Interesting, question regarding draw thru vs. blow thru.

where air is being forced back through the compressor housing on the turbo because of built pressure from the turbo spinning. a bov relieves the built air pressure to allow the turbo to maintain a nice smooth spin withought loosing very much rpm. The compressor surge can eventually damage your turbo over time by putting extra strain and pressure on the bearings.

It sounds like a bouncing whoosh sound more of a higher pitch to it also.

The throttle closes, but the BOV doesn't open. The compressor is still spinning, but there's no place for the pressure to go. The wheel either stops spinning or even spins backward so the compressed air can escape. Meanwhile the turbine on the exhaust side is still spinning so they fight each other. The result sounds like "CH-CH-CH-CH-CH-CH-CH-CH-CH".

ahh thanks for clearing that up guys

You go rich between shifts cause you blow off metered air. That is the main thing. The idle wasn't ever an issue as the bov closes at idle. HOWEVER, stock bov's or recirc valves aren't fully closed at idle and can't be adjusted down. That is why everyone got away from running open BOV with draw througy setups.

Brent

since my car has been turbo i allways ran unricirculated BOV, never an issue here, i doubt anyone on this forum has my BOV (BLITZ Old skool Trumpet) but maybe some 240 do and some skilines and some supras are the only cars i have seen it on.

I think the problem is as stated above , just cause you buy a BOV that does not mean its ready to go ,you need to adjust it to fit your mods on your turbo motor to avoid surge build up