'97 2.2 cavalier

My son's and I have installed a cold fusion "wet" nitrous system on his '97 cavalier. We have a twisted sanity box that hits 50% when the throttle is fully opened and an additional push of the button gives it 100% until the throttle is backed off from full. What I'd like to know is will it hurt a stock 2.2 if 50 horse jets are used , if the full 100% of the fifty is not turned on until second gear? The reason I am concerned is that I have no way for ignition retard. Thanks