difference between bypass and blowoff valve
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From: Broken Arrow, OK
difference between bypass and blowoff valve I think I understand the differences between a bypass and blowoff valve, but is there a difference in sound? I guess it was my understanding that a blowoff valve makes that recognizable turbo sound that we all know of. Now does a bypass have the same sound or would it be harder to hear?
Originally Posted by vhgjk123
Hey man, I met you last night at Sonic, I was the one with the pewter turbo SS. 
Anyway, if I remember correctly a BOV and a bypass valve are the same thing.
Anyway, if I remember correctly a BOV and a bypass valve are the same thing.from what i understand, BOV's are only for turbos as they open at X amount of pressure. the bypass valve is for superchargers because of the different pressure under load and at idle due to the pulley.
all i know is if you put a BOV on a supercharger, it will make an annoying chirping sound, or something to that effect. maybe someone else can pitch in and give a better explanation.
Same idea but the bypass dumps it back pre-turbo/blower and the BOV (typically) vents to the atmosphere. Like whitt said, the bypass is open under vacuum conditions and closes under boost. The bypass is going to be a lot quieter than a BOV.
