We are running a 2.2 LN2 motor on a circle track application. We have the head shaved 30 thousandths, aftermarket coils, and run leaded 111 octane. The car reaches a peak of about 7500 rpm- 8000 rpm each lap. I am currently running the NGK TR55 (3951 I believe) plugs and its time to change them again. Would it be beneficial for me to run a step hotter plug or the standard heat range plug which I have been running? We normally gap them at .045 if that makes a difference. Also, if a step hotter would be beneficial to me, what would be the part number for the copper plug? Thanks for all replies in advance.

stock gap is .060, open them up!

Also stock number for the NGK's for a LN2 is 2683. The 3951 is for a LD9.



FU Tuning