Originally Posted by goinloco1
the 103 / 104 should last at least 20k with no problem.
103's fouling? mines stock other than plugs and steeda sri (no tune) and I run minimum 91 octane. reason being... my gas milage increased as well as butt dyno power (well actual dyno was 114.5whp). 89 ethanol was giving me just shy of 25mpg, 87 was about 26.5mpg and premium shot to 29-35mpg (averages 31).
only about 6k on the plugs, but no sign of wear or stress. and they've seen road trips, auto x, and drag racing in that time.
This sounds promising to me. To this point I've ruled out the 103 plugs because I didn't want to go to a colder heat range, given this location (Twin Cities). But if you're runnin' 'em and having no problems, then I may give 'em a shot. The other complication for me is that I only live 3 miles from work so sometimes I'll start my car in subzero temps, warm it up for about a minute or two, then gently drive it (takes another minute or two to reach normal operating temps). By the time it's fully warmed up, I'm halfway to work and have only another mile or two to drive it.
Aww heck, as I think about this, I think I'll just keep the 104's for winter use and swap the 103's in for the other 3 seasons... same thing I do with my wheelsets (one dedicated for winter). Changing plugs really is a breeze in these cars, anyways.