Originally Posted by
cobaltssoverbooster
The cavalier ECUs are generally Alpha-N mode controllers (TPS and RPM) with the 2.4 LD9 Twin Cam computer having an option to be flashed for a speed density (RPM and Map) mode for use with that GM/Eaton supercharger application.
The map in Alpha-N isn't really used for anythign other than initial baro reading and cross check, and idle and cruise modeling. If you do change the map, then GT is right in that your going to need to change the map sensor linear and offset values to match the calibration information for the installed sensor. If you don't, the ecu thinks the sensor is a 1 bar even though a 2 bar is installed.
It would help if you post your tune file so other users can verify the ecu control mode and the settings you are workign with. If the original has the GM OS for the supercharger then the tuning instructions will be different from the typical n/a OS.