I have not had my car for long so decided to have a look at the plugs. The colour looks good but I see that their NGK TR55 GP. From what I've read its an iradium plug which is probably not the best for a supercharged car? They look like they are in really good shape but the reason I checked them because Im getting KR when not in boost? I notice that if Im cruising along at 60 mph on a road with hills I can get upwards to 8* KR when going up the hill and the engine is under load? I get very small amounts >1* under boost. I guess Im asking 2 things;
Could the plugs be the reason for this KR?
If I need to change plugs please tell me what a good plug for these cars preferably (champion) What heat range?
Thanks
