Marc:
The ctrical area is 4000 rpm's plus. Your car will go into detonation somewhere above 4000 rpm, at an a/f of 15 or greater. The typical stock viper a/f curve tends to tail down slightly (enrichs)as rpm's increase. The a/f ratio should be checked between 4000-4500. A stock viper is approx 15 at 3500 and will drop to 13.5 at 5500.
One problem with the viper is the stock champion plug. The extended tip can can actually cause detonation by glow-pluging. The NGK 7252 shows no hp decrease on the dyno and will reduce the chance of detonation.
I have been playing with my a/f ratio and have over 40 pulls. One caveat is, my pulls are on a Gen I. There is very little penalty to pay in hp by running a little rich and it is safe.
