Glad you got it fixed, the next thing I was going to suggest was the wastegate... I always work backwards towards the turbo...

 

At 25 PSI it will be 100% open. The reality is that the flapper valve will "crack", or start to lift off its seat, way earlier however. It'll be halfway open at a boost level significantly lower than 25#. FP rates it to be fully open at 25#. Do you think that it is still 100% shut at 23#, or even 16#?.... Well, it's not.

Here is my own empirical example: I have an 18# FP WGA on my Green turbo. However, if I run it on spring pressure alone I can get it down to 14 PSI. That is, if I disconnect my MBC and run a hose from the WGA to the compressor discharge nipple and set the actuator rod at its loosest setting I can get a base boost pressure reading of 14 PSI. And it is supposedly an 18PSI FP HD actuator. So, for it to be fully open by 14#, the flapper valve on my turbo had to have started lifting up off its seat way before that 14# level...... and it is an 18# FP actuator.

I still say that if you are not preloading your actuator at all, then your turbo is spooling way slower than it could be. The wastegate is rated by FP to be fully open by 25#. To be fully open by 25#, your flapper is cracking and lifting significantly, a lot earlier. This is slowing your spool way down and limiting midrange torque.

EDIT: Of course with your setup and the torque(515 ft/lb)that it produces who cares about dicking around with preloading the WGA anyway? You are producing major league power! LOL & Kudos.

 

Has anyone given some thought to placing a vacuum generator on the vent from their boost controller? That might give a much better control on the hysteresis range of the wastgate