OK I understand what the gap is and how to adjust the gap. What I'm not sure of is the effect of the adjustment I'm making. I know that stock eco plug gap is .042. I was told I should bring this down when being boosted so I moved to .030. I started getting the 300 random/multiple misfire code. I was also told that I should open up the gap when moving to a msd so i widened it out to .035. I talked to the guys at Rsm and what if any codes they are getting with thier race car. They are still using a totally stock ignition with stock plugs gapped at .048 to .052. It was suggested that I may need to go as high as .060 with an MSD.

SO what does moving the gap up or down effectively do in the first place because I dont quite understand the thoery behind it totally



1989 Turbo Trans Am #82, 2007 Cobalt SS G85

when i removed my stock spark plugs out of my 04 eco...befor i put the autolite 103's in....they were gapped at .060. So i gapped the autolites at .060 also and never got a misfire code since...runs smooth no kinda of signs.

A bigger gap gives you a bigger spark, which should lead to a more complete combustion in a NA car. When you go boosted, the spark can be "blown out", which is why you reduce the gap. I'm sure there are others who can add to this if I've missed anything.


15.3 @ 89.97mph, 14's on the way?

For Sale:
Getrag '00-'02 2.4 8000kms $800

my TR6's are gapped at .040 no problems here



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