0-15 psi, as quick as I push gas pedal and above 75 mph - I ll get up to 20 psi, no knock, FMIC, TA-49, no alky (yet), 93 Octane, no race gas! When I race on drag strip using 110 octane, I can turn boost up, maximum to 24 but my gnx replica is a daily driver with 110,000 miles driven from WI to...