no need to raise so much the limiter...basically you took to 2.25 bar+1 bar of atmospheric press....because the pressure sensor "law" to a maximum of 1.5 bar press turbo+1bar press atmospheric in all f? 2500millibar...and that the voltage of the sensor correspond to 4.5 volts...
as you have recommended if you want more press turbo 1.5 you have to adjust the map of the voltage sensor turbo pressure...
or you can mount a sensor 3bar or 4bar totals and adjust the map of limitation turbo f temp....