Exactly!

If you're sourcing boost for the MBC at the compressor, the MBC is not going to be able to compensate for downstream leaks or other causes for fluxuating boost. At face value this might seem like it is a bad thing. IMO, however it isn't. If you've sourced your MBC at the intake manifold and as a result, compensating for any leaks between the compressor outlet and the intake manifold (and there will be some) then there's a good chance that you'll be masking the effects those leaks and quite possibly pushing the turbo outside of it's efficiency range if the leaks are bad enough.

The question is, what are you really trying to control? Are you trying to control the level of boost in the entire intake tract or are you trying to control the output of the turbo? Personally I'd rather have precise control the turbo and deal with the leaks than mask them.

 

So propellerhead are able to hold full boost to redline?

 

My car is currently off the road but back in November I was dealing with a crap load of leaks. Once I was leak free and my BPV closed correctly, it would hold full boost to redline. If the BPV (1g DSM) occasionally failed to close correctly then I would see taper. If I sourced my MBC at the manifold I wouldn't see the taper at all. It would be masked by the MBC compensating.

Bear in mind that I was running the BR440 which has plenty of efficiency to run up to the redline on a 2.0L at 21 psi and not suffer any taper.

 

It's normal. I even put on a JDm MR Diverter valve and no difference

 

I have my boost source at the intake mani and mine still tapers. Right at about 2psi. I hit 20 in the midrange and fall to 18~17 at redline. I am all stock BTW, maybe it will hold a bit better when I get my 3" TBE.

 

That doesnt seem like too bad a taper