Turbosmart MBC won't hold steady boost! Normal??

[ShimiBoi]

Been reading up on MBC and "boost taper". It still feels better with the Turbosmart MBC. I have it on the first click, which is ~9psi. When I get past 4k the boost starts to taper off to a steady 7psi. Is this normal? Did you guys that have tried this find any way around this? Thanks in advance!

Some background info:
Stock block ka-t
Bottom mount T25 @7-9psi
Sr SMIC w/ Sr piping
Sr 370cc injectors
Z32 maf
Greddy RS recirculating BOV

[EsChassisLove]

It's a T25.

They don't hold boost for shit past 5000.

[ShimiBoi]

Good to know, I thought it would hold 9 til redline but it will hold 7. Will the MBC shorten the life of the turbo by a lot?

[Croustibat]

They dont hold boost on a CA18DET. And the SMIC is horrible, on CA and SR.

What do you expect on an engine that has 600cc more displacement ?

[EsChassisLove]

No it won't shorten the life of your turbo. The way you drive will make that call.

[ShimiBoi]

For sure. It holds 7psi all the way no problem, just wondering about boost taper. Or if anyone else had experience with it.