Manual Boost Controller issue

I bought one of these MBC's ready to fit with my TD04:



http://ift.tt/1mbAZ1k



Wasn't going to bother with it on the GT15 but decided to give it a go as I've got a bit of wastegate creep, it gets up to 15 psi as it should but then the last few psi only crawl up.



With the MBC fitted, the boost flies up straight away, but the problem is that even with it set as low as possible it's still at 25+ psi. Should I try a different spring in the boost controller?

from the last news http://ift.tt/1ofjkV0

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