I am having some serious issues with boost. I was maxing out my tru-boost at 26psi(which i thought there might have been a boost leak). The car was brought to a local evo guru, a PPI ported manifold (new gasket )and dejon intake was installed. After that , the car was boost tested...it was fine.
After that I installed a forged mbc because of the prior boost limitations. Now the car won't boost past 15lbs, no matter what !! The bov doesn't sound nearly as loud as it had before, and I can't here O2 dump release the exahaust gas.
Here is what i've has been checked:
1.every frigging t-bolt on from the turbo to the intake manifold
2.every vaccum line on the intake manifold,wastegate,bov
3.I swapped out the forge bov for the stock to see what happens, nothing
4.checked vaccum lines for restrictors
5.I even switch wastegates, and played with the eye bolt, currently its down as far as it will go on the rod.
6.I have tighten and loosened the mbc and bov to their perspectives extremes and only get the boost to flucuate by 5 psi.
7.reused the tru boost....seeing the same boost
8.reused the stock boost controller...saw lower boost.
9.I've rechecked the wastegate for opening and closing via putting a screw driver in the eyebolt and lifting to check if the wastegates were frozen.
My only option now i think is to disconnect the wastegate and see if the turbo will boost past 15 psi.

 

I honestly sounds like the MBC is not hokked up correctly or not operating properly. How do you have the lines routed from the MBC

 

that has been checked and rechecked! wastegate to the side and boost source to the bottom

 

You have an adjustable WGA? I would hook that directly up to the BOV and just run spring pressure. Turn the waste gate pressure up all the way and measure the boost. If all of the different boost options are not working, maybe the car is in a limp mode due to the tune / you changing the boot too high.

Not sure though. Weird problem for sure. No CELs correct?

 

I'm not sure if this is the case but did you buy the RX mbc? I read when I was buying my mbc that the RX allows only up to 5 psi adjustable from stock but it's very precises and allows 1/2 psi increments. Here's what the ad said.

When you switch over to tru-boost can you go past 15?

This kit has a ceramic ball instead of the 316 stainless ball that comes in our other valves. The ceramic ball only weighs a fraction of what the stainless steel ***** weighs. This weight difference allows the ceramic ball to act very quickly as it is constantly changing directions during operation. The ceramic ball in conjunction with the use of a lighter spring will allow very fine adjustment of boost up to 4 to 5 pounds of boost over stock. Boost has been able to be adjusted in half pound increments very consistently with this valve.

http://cgi.ebay.com/ebaymotors/HALLM...Q5fAccessories

 

Your hotside might a crack in it..pull that ***** off and see.

n