I've heard that boost starts to cut back at higher RPMs and I never really noticed this effect, but today I decided to see what people were talking about. I was surprised to see that at about 6000 RPM, boost dropped dramatically from 14psi to about 7psi! Is this normal? I'm thinking my catless uppipe and 3" exhaust might have something to do with it,.. or I have an exhaust leak,... or its normal,..
Beware, the stock ECU retards the ignition and richens up the fuelling if you run high boost and revs. You will still get some benefit, but not as much as you hoped for.
More importantly, beware the high EGTs that Gerlando mentioned above if you have full boost on part throttle. I suggest that if you use an MBC then you should pick one that allows you to avoid this problem (such as the TurboXS one).
Oh yeah, a MBC will definitely help. Just get one that combines the ball and spring design with the bleed off valve type. That way you can set the ball and spring to a lower boost for part throttle and set the bleed off one to high boost for full throttle.
Here is a link that shows you how to make one of these type of MBC's.
Gerlando, you already have the first part of this, all you have to do is add the needle valve section after the ball and spring MBC and set the ball and spring boost to around 7psi for partial throttle position.