Alright I performed a standard leak test.

I could not get the system to hold over 10psi because my Hallman Pro MBC was leaking like crazy from the bleed hole. I have done lots of searching and I see that this bleed hole is a design. Although if this is true why did it leak at a boost level way less than what it was set to ~ somewhere around 20psi?

I used a nipple from another boost controller and put it into the Hallman and all of my leaks from the MBC went away. Shouldn't the MBC be part of a boost leak test? The nipple I used did not have the hole drilled into it as the Hallman nipple did. They say this hole is designed there to bleed boost as if it was not there then the Wastegate would remain open. Although on Hallman's site they say their valve is NOT a bleed valve. Am I confused here?

I could not hear any other boost leaks. I was amazed that somehow the less than 10psi could make a boost leak from this design in the Hallman.

Please help. If there is a better MBC I have yet to know about it. Although this design in their product does not seem like a defect....

 

pressure 1st has to "pushed past" the spring and ball, then to the WG line. w/o that bleed/reset port, you will not be able to vent off pressure in the WG line and you will not build boost after that......because the WG stays open from the pressure.

thats how a mbc works.

 

MBCs are SUPPOSED to leak, that's how they work. Bypass it when you do the test, eliminate any other leaks, then reinstall the MBC and go for a test drive and adjust it accordingly.

Hallmans are some of the best MBCs available. Several tuners swear by them.

 

It should make noise through the bleed hole depending on where it's set. When my purges air during a boost leak test, I just crank it down so that it doesn't leak up to 25psi. Then, after I'm done with the test, I put it back to my preset level. Currently, I run 26psi daily, so when I do boost leak tests, there is no leak at the MBC. I use the Forge UNOS, but I also have a Hallman and it behaved the same way.

 

I thought about a different MBC although If this is really not a fault of the valve then it seems silly to buy another one.

I replaced the nipple with the one hallman originally had there and the boost appears to be holding pretty solid amount.

So is it best to include the MBC in a boost leak test or just omit it?

 

I still swear by them. It is a good valve. I will omit it next time when I do the test. I am glad I had no other leaks. Not too bad after over 6 months owning the car. Stock piping is pretty good I guess.