spark gap for turbo application
.035 for about 450-600rwhp
.030 for about 600-750rwhp
less for over 750 and some switch to an even colder plug
I run the R5672A-7, 8, 9, or 10s in the cars i deal with. make a few pulls on the dyno to see where the heat is on the plugs and go from there. Once you get a plug with all threads showing good heat then you can work on the gappage, which I generally leave alone but check when installing the plugs mentioned. from the 7 gapped at .032 to the 10 which i believe is gapped at .026. A cold plug with a tight gap will bring a little bit of heat back so you dont have fouling issues. If you are looking to get the most from your combo, you will use something like this to help lower the risk of detonation. Spark plugs act as heat exchangers....Read and understand this at will.

