I have installed a MBC and Blitz DTT a week ago ..Today i wanted to see how it actually held boost above 5000. I set the boost to 1.45 bar almost (21.3 ). Well ..the boost drops above 5000 to 1.38 and than to 1.28 around 7000 rpm. and around 6500 i start hearing a hissing sound like an air leak. Now.
1 Is that normal i mean the boost drop despite MBC. It holds boost nicely till 5000 than it is like I said above
2 Where is the hissing coming from BOV? mine is stock
3 Is it the ECU that ultimately controles my boost ( I know it will cut fuel around 24 but i havent gone that high at all) If so what the heck MBC is for?
Meanwhile my MBC is something called Joe P mbc i don't think it is the culprit or is it??

 

Could be the mbc. I never heard of a JoeP ? mbc

 

im thinking mbc too
happens to everybody who runs 21-23psi with mbc