Hey there, new to tuning LS1's. Have got an twin turbo LS1 powered jetboat in my shop. I have removed MAF sensor, and fitted a 3 bar MAP sensor. I want to upgrade ECU to OS5 to handle fuel/spark under boosted conditions.

Question is this : Do I just reflash ecu with the OS5 version based on the original OS number ? Reason I ask is because obviously engine has no transmission fitted now so is there a better OS to base OS5 on?

Also what happens to OS when changing LS1 vehicles from manual to auto or vice versa?

Cheeeeers
Brad