can someone tell me if there is a difference between a supercharger bypass, blow off valve and a turbo blow off valve? i have a vortech maxflow valve on my ss right now and it can be set at 3-6 hg which should 6 hg is = to 12.72 or so . but when i ran it on the stock 6.0l it was seeming to open at about 8 or above but i wouldnt make more than 11-12 psi. but i coul dhear it opening before i hti that. so i added a bigger spring but have no way of testing other than on the truck. anyway im wondering if turbo and sc bov's are the same because the moutnign flange i have is somewhat universal to hks aand greddy style bov's so if i could just change to one of them i am sure they have one good for 15+ psi ( what i plan on running) i just dont want this thing to be opening on me and gettign rid of my presious boost.

 

anyone?

 

turbo charger blow off valve prevents turbo shutter from pressure being forced into the closed butterfly valve when under high boost conditions when you let off the throttle quickly. In other words, it relieves pressure/boost. Are you thinking wastegate? Im not sure but i dont think they are interchangeable.

 

well from the reading ive done and a few calls , i guess bov for superchargers, ( could be for turbos to) dont open at all under boost. but the weird thing is i could start to hear mine open at a certain boost level. but for now im going to try running the larger spring and see what happens.

 

It sounds to me like your bypass valve is regulating your boost pressure, like a wastegate would do for a turbo. The blowoff valve does not (usually) regulate boost, it is more like a pressure relief than a pressure regulator I believe. Your pulley should be the only thing to control WOT boost, correct?

 

yea thats what I was getting at, I think they are a totally different device. I dont have any supercharger experience but it sounds like its a pressure regulator that opens once you've hit the set boost pressure(spring tension), whereas a wastegate on a turbo bypasses exhaust gasses around the turbocharger to keep it from overspooling/overboosting and a BOV is just a pressure relief valve it doesn't open until there is a pressure differential between the intake manifold and boost/charge pressure.

although i could be totally wrong here.

 

you guys are both toatally correct i was the one misunderstanding them i think the reason my bov was openign is because the boost line was very small so thaat should take care of it

 

BOVs work under engine vacuum not boost. When the engine pulls a vaccum, greater than the BOV is set for, the valve opens and vents the excess pressure in the intake piping pushing on the throttle plate (IE the throttle plate will be completely closed or close to it) to the atmosphere. The vacuum/boost line from the intake manifold to the BOV opens the BOV when the vacuum is reached that the BOV is preset for. When the Intake is under boost that pressure actually helps the spring in the BOV hold the valve shut. The BOV should never open when the intake manifold is under boost. Under boost the pressure on either side of the BOV should be about equal plus the pressure of the spring should always hold the valve shut.

 

Don't forget the most important thing about BOV's on Turbos.... .... They sound AWESOME and scare kids & Old people!!! LoL

 

The bypass is to make the supercharger work less when not needed, it bleeds the boost back into the top of the charger at cruizing speed so basically you are just turning the rotors with no resistance.

A turbo BOV bleeds off the boost when the throttle plate shuts and the boost doesnt have anywheres to go, I assume the bypass would do the same?