View Full Version : S&S IST IGNITION

04-14-2007, 10:00 PM
Mike how good is the S&S IST ignition at autotuning its self for optimum performance? I like to experiment with different cams and intake & exhaust systems which may require different ignition settings to optimize. I do not have a talented HD dyno tuner in my area. Is this ignition system really that good at autotuning its ignition curve for different engine applications and producing as good an ignition map as a decent dyno tuner? I have seen some opinions on various boards that think it is very good at producing conservative safe ign. maps that will keep you out of trouble but is not agressive enough to maxamize HP & TQ and other guys that swear by them. I am not interested in tuning ign. advance to the ragged edge of detonation but do not want to be so conservative that I leave a lot of power untapped. If this ign. system will get close to ideal settings, and reset its curves when I make changes, it is worth the expense to me. I currently am running a DTT system on my 124 inch carburated 03 dyna twin cam motor. The cranking comp is 205 but can run as high as 225 with shorter duration cam selections. I am very careful about gas quality and any signs of detonation.

04-16-2007, 10:00 PM
I like the IST ignition and have seen it make good power on several 124's. S&S motors with IST have one more year warranty vs those without so they put a lot of faith in the system. But we have not done an A/B test vs other systems to see if it really does produce the best possible power. It's funny because we were recently having just this discusion on a 124 install. I also must admit I do not know how conservative the programmed retard from detonation is (its theory of operation is great). My inclination would be to stay with a manual system like the DTT and simply ramp up until detonation occures and then back away the least amount possible.