I know nothing about Starquests, but are you sure you should be trying to get around the fuel cut? Do you have proper supporting mods to run that boost like injectors, some sort of engine monitoring like datalogging or gauges at the least, and a tuning device? If that's a "magic number" for ideal boost that you've found on a board, I wouldn't trust it. Back it down a few psi.

Have you gone to the starquest board I linked in your other post?