Spark Plugs-Map Vacuum Pressure-S-AFCII Mapping Q's

[20vWill]

If your fuelling is sufficient, I would keep the 6 heat range and try reducing the gap by 0.1mm increments. You will get a stronger spark which should help with the low-medium rpm rich-running characteristic of the throttles. Changing to heat range 7 will make running worse in these conditions.

You'd only need to move up a heat range if you're running substantially higher combustion temps with higher power. I doubt you will be at this stage, especially on stock or even mild cams. Maybe try 7's when you are pushing 160 ponies? Even the 20v runs 6's and that is a very hot running engine (in terms of combustion temps).

And yeah, stick to pikey copper NGK-R's, but keep them fresh. They are an excellent plug and produce the best spark (better than platinums, iridiums and all that other HKS/Blitz rebranded Denso stuff), just don't last that long, especially when experimenting with fuelling and ignition.

Once your halfway sorted, you can change them every other oil change. Until you have a decent map, you will need to change them frequently. Just buy a box-load at bulk discount. I can get them for you cheap if you want mate.