You can see your base pressure by removing vacuum hose from the supercharge outlet elbow / top plate. Also why not to install
analog boost gauge to see your posivive and negative pressures. Widebands for both bank higly remmoneded. Then you don't need to expect your values.
It can be dangerous.

 

Thanks! I monitor everything through obd2, boost shows at around 11 most times, or 25, 26 combined with the atmospheric pressure