2G Boost from BOV vacuum line

[2ggst1998]

Thanks yall, ima swing by the auto shop and pick up a set of bpr6es and see uf it does anything, the turbo install should be done by tomorrow so ill fill you guys in after its done, ill also give it another boost leak test just in case.

 

[S4785]

Is there suppose to be any boost coming fromthe bov vaccum line? Is this a bad bov? The vaccum line pops off under wot

Zip tie the vacuum lines

 

[Chumpaumpalumpa]

Hmmmm those seals failed on me immedieatly with those style injectors... may want to check. Those should require an fic seal kit

FIC seals always leak anyways. Not terrible, but they leak.

 

[enriquez2000]

FIC seals always leak anyways. Not terrible, but they leak.

Not as bad as using those dsm ones on that stule injector. Mine literally exploded

 

[Chumpaumpalumpa]

Not as bad as using those dsm ones on that stule injector. Mine literally exploded

so did my FIC ones but they were very old.

 

[enriquez2000]

so did my FIC ones but they were very old.

I destrpyed 2 sets of oem before i figured it out... oh well live n learn

 

[Mike_GST]

I think a lot of people are confused on how bov's and wastegates work. The bypass valve is normally closed due the the spring pressure this holds the bov shut but not well enough the reason for the vacuum/boost line it 2 fold. Under boost above spring pressure boost fills on top of the diaphragm helping the spring. When the throttle plate closes between shifts boost turns to vacuum the line then vacuums above the diaphragm and over comes spring pressure opening the valve. This is the only real reason for the spring waste gates work in the same way. Just reversed vacuum helps the close and boost opens mbc bleed off set psi to reach higher boost psi than the spring can handle. But if exhaust pressure surpasses spring pressure the flap will creep open no black magic just good old mechanic theory most important thing when coming to turbo cars vacuum lines run both ways vacuum under vacuum and boost under boost. N/a cars only run vacuum. I think this is a concept some people over look when moving from 1 car line to another and y boost leaks cause so much problems so some leaks will hold vacuum because it's suckling the seals in. And there may be something there that helps the sealing like a lip or boss around the injectors. But under boost these seals get pushed out with nothing to hold them in place remember the KISS method. Don't over think things and. Keep It Simple Stupid.

Oh man! That made universe making sense again!
I rejected two BOVs because of leaks through the recirculating hose.
Now I see, probably the BOVs were fine, my leak test is the one that's missing something.
I was applying pressure on the boost line with the vacuum line disconnected.
This way, the BOVs holded just 2psi. Coincidence? NOOOO.
2psi is the boost the BOVs can handle just on the spring force.
After that, it needs help from the vacuum line (supplying boost) to keep the piston down sealing the bypass.
I can't wait to test for leaks again with the vacuum line pressurized too.

I'm almost sure my stock BOV is bad. The spring must be ok, but the diaphragm not.
That could explain why my car runs ok on low boost (just on spring), gets all shaky on middle boost and can't reach high boost (leaking boost through the diaphragm).

THANK YOU!