Hi.

Here is the whole story short:
Fully track prepped EVO X, built 2.0L 4B11T. Made ideal figures on stock turbo with aftermarket quality header.

Installed ATP GTX3067R internally gated - worked just fine. Same spool as stock turbo but more top end.
But we thought to try a GTX3076R for more power since the turbine housing shares both turbos.
We took a used GTX3076R which worked very well on our customers STI.
Then replaced CHRA with compressor housing on EVO X and.... turbo wont make more than 15psi. no matter what we try, even closing the gate with heavy external spring and setting WG preload to 25psi...

What the hell can be the cause of this issue?

Please help!

 

Test the wastegate with compressed air and see when it opens and to hear if possibly air possibly passing by keeping if from seeing full pressure. I tested my external wastegate to make sure it cycled before running it this way.

 

Did you do a boost leak test? Maybe one of the housing isnt sitting properly and is leaking. Also test the BOV.