I am tuning a CTS-V with a 2.55 upper, 9.0 Lower, intake and it makes about 17psi and it seems that no matter what I am hitting a brick wall around 3900-4100rpm (205-208KPA). I have tried maxing out all airflow tables, boost limit tables based on MAP, temperature, etc.
Anyone run into this? Unless I am missing a table somewhere as this is the highest boost E67 I have done to date...