The unit you have, while just fine on the motor, will let the nitrous power blow through the convertor. The factor here is slippage. A nitrous convertor is much tighter on the motor, but will allow more stall when on the juice. We went throught this recently and found our power was blowing through the convertor and the car was slower on juice than it was on the motor. The stall was sent back for a nitrous tune and it has worked really well. You could have your same convertor set up for juice far cheeper than buying a new unit.