Power Brake Booster Check Valve for BOV vacuum source

[badandy]

Are any of you using the power brake booster check valve as a source for vacuum to your blowoff valves? If so I have a quick question that I have not researched yet.

Does the one way valve in it function just for the booster side of the "T" or for the entire "T"? The reason I ask is because I have a Tial blow off valve that will still allow compressor surge before it blows off. I know the spring inside the unit can be swapped out for a lighter spring which may be my problem however the spring I have is the correct one for my idle vacuum according to Tial's website.

If the spring tension being too tight isn't my problem than my theory was the one way valve inside the booster "T" may be slow to react coming down off of being in boost...not allowing vacuum to reach the blow off valve quickly enough...thereby causing my compressor surge and the finally blowing off. I have noticed that when barely in boost and letting off the valve seem to react quicker than when at higher boost levels.

When I have time to get under hood I will switch vacuum sources and go for a drive and that will likely give me the answer I'm looking for...but in the meantime I thought I would pick some brains.

[turbovanman²]

If there is only the brake boost running off the vacuum line, then you are correct, there isn't any flow until you step on the brakes but if you are tee'd off before the check valve, then you will have flow when needed. If you are tee'd after the check valve, then you will have issues.