What I meant by delay was it would not let it open as easily. There would have to be a more significant difference between boost pressure and drive pressure depending on the strength of the spring you used.
Why no blowoff valves?
- Thread starter Pony Express
- Start date
The spring in mine is what positions the piston to the closed position to begin with. If it wasn't for the spring the valve would never shut after blowing off. It would just stay in the open position. I've tried it 
You guys are right, the spring does make it harder to open, and stay open. This is why I installed that one way check valve. Keeps boost pressure signal inside the BOV higher and longer. Without that valve it blew open only under hard load and quick drive pressure loss, and would only open for a split second. Not enough to keep the turbo from barking.
Oh and your question about it 'blowing off' all the time. Its still not a gasser with a throttle valve so no. All depends on how its setup. I first set mine up to only blow off when a turbo bark was imminent. But then loosened up the spring a bit to where it really only blows off under moderate acceleration. It is more emphasized at lower RPM.
You guys are right, the spring does make it harder to open, and stay open. This is why I installed that one way check valve. Keeps boost pressure signal inside the BOV higher and longer. Without that valve it blew open only under hard load and quick drive pressure loss, and would only open for a split second. Not enough to keep the turbo from barking.
Oh and your question about it 'blowing off' all the time. Its still not a gasser with a throttle valve so no. All depends on how its setup. I first set mine up to only blow off when a turbo bark was imminent. But then loosened up the spring a bit to where it really only blows off under moderate acceleration. It is more emphasized at lower RPM.
Last edited:
Also wanted to point this out. The one-way check valve I used is not a typical valve that only allows one way movement. Its some kind of vacuum restriction one way valve. It still allows flow in both ways however allows a lot quicker flow one direction vs the other direction. So this prevents the boost pressure from just staying inside the BOV and keeping it open.
im still not completely clear about why you had to tie into the wastegate line. im gonna be setting up a BOV for my s472 which has no wastgate
I just needed a boost reference line and that was the easiest to tap into. It has nothing to do with the wastegate.
i see. i couldnt figure out how it affected the waste gate at all. i have been thinking about it for a looong time. glad to know ive been wasting my time lol
did you leave a link to the BOV you're using? i was lookin at getting a 50mm tial but they are still over 200
Mine is an Apexi I got from some ricer off of craigslist. No idea on the specs lol. I wasn't sure if it was going to work so I just went with the first cheapo I could find. I do know you want to find one that has the max air flow potential. I believe he said this valve was rated for like 15psi of boost, or something like that :rofl:
all the cheapos i see are rated for like 10psi. i guess it doesnt matter since we are using drive pressure to overcome the boost and keep it shut. i guess the air flow is all that matters. and one with a small spring
im trying to understand the check valve and boost reference line, the drive pressure will keep the valve closed under load and once you let off the throttle the boost should then be more than drive therefor pushing the bov open, once you touch the throttle again shouldnt the drive pressure shut the valve again?
I don't think your set up is the same, no offense. You don't even know if it works.
i dont KNOW if it works, but i cant see how it wouldn't, and it is almost exactly like burnouts.....so im assuming it will work fine
nope, would rather sell it and throw some extra money at a new intake. this plastic hacked ATS aint cuttin it.
So if the BOV only has one hook up port on it. run that one for drive pressure set the spring loose or what ever works. and thats it? because all the bov's i see only have one spot for a line.