Manual Boost controller Bleeder valve Leak??

[JoEgsX90]

Hey everyone, Have a MBC with a litttle bleeder valve on it...When i had it conected during a Boost leak test i noticed it was leaking?? Putting about 11 psi in the system and it hisses out of the hole. Ive read other places any MBC with breather valves arent really good because any leak in the system isnt good.?? Im trying to get some straigh answeres with this....And also because the way i have it setup i have the boost sourse t-eed into the bov vac. line and other goes to the wastegate. Ive read alot of places this is not right way, and other people say its fine, iduno? Im running a 16g so no nipple on the turbo and none of the intercooler pipes have nipples. So Wondering whats better MBC with a breather valve or not?

 

[jshuman]

When doing a boost leak test with a bleeder style mbc, it is recommended that you bypass it. I usually just remove the source line and cap it for the test.
As for your vacuum line routing. Most recommend that you have nothing tapped into the bov line. Just run it straight off of the manifold. For the mbc, i would advise you to use the compressor housing or j-pipe for the boost source.

 

[Zmann42087]

That boost leak is to be expected and is just your bleeder valve operating normally. A bleed-style MBC works by leaking off pressure from the vacuum hose that runs to the wastegate actuator (WGA). Your car runs higher boost levels as it takes more air pressure in that vacuum line before the wastegate "sees" enough pressure to open. Whoever told you bleeder valves were not the best is correct. Because of their design, pressure builds gradually at the WGA and consequently boost spikes are common.

A better choice is a ball-spring type MBC. These valves use a ball to block the air pressure in the vacuum line running to the WGA. The ball stays put until the spring pressure holding it in place is over come by the boost pressure. Because there is no gradual pressure build at the WGA, boost spikes are eliminated.

Like shuman said, tapping your MBC off the BOV line really isn't ideal either. I recommend running it right off the compressor housing if possible.

Also, here are a couple pictures I found showing the two MBC designs. The bleeder valve is on the left and the ball-spring valve is on the right.

 

[DSMunknown]

http://www.dsmtuners.com/forums/newbie-forum/241831-no-boost-leak.html

 

[JoEgsX90]

Mine is a bALL SPRING BALL with a bleeder valve and it leaks under a boos leak test.

 

[snowborder714]

Read post #2. You need to disconnect the boost source line from the MBC and cap it off when doing a boost leak test.