Ok you can disable the clutch pack and run in 2WD to enable you to get a constant baseline for tuning which is what you want but that actually is not going to give you an accurate absolute whp power reading is it ?
Considering you put this thing on the track and 20minutes of hard driving later it goes into 2WD tells you the transmission losses are pretty high to generate that sort of heat in the front/rear clutch pack.
10% drivetrain losses for an AWD car wouldn't be out of the question so you would not expect any more that 270whp at best, if the clutch pack has to start shifting power about that's all additional losses and you would find yourself at 250-260rwhp in no time in real world driving.
Considering you put this thing on the track and 20minutes of hard driving later it goes into 2WD tells you the transmission losses are pretty high to generate that sort of heat in the front/rear clutch pack.
10% drivetrain losses for an AWD car wouldn't be out of the question so you would not expect any more that 270whp at best, if the clutch pack has to start shifting power about that's all additional losses and you would find yourself at 250-260rwhp in no time in real world driving.