Thread: spark plugs

so, after sitting with my father and listening to him rant about how shitty non american cars are and how no matter what i do his big block will make his bitch anyday for an hour , we got on the discussion of spark plug gaps. he was saying that since i am running a stronger ignition i would benefit from running a larger spark plug gap. is there truth to this?

Yes you can benefit from it. When I was running 7's on my NA/Juice setup I opened the gap to about .040-.042 iirc from the .035, car drove considerably better. WOT results were the same on the dyno.

what kind of gains did you get on the spray with the bigger gap?

OP, your father speaks the truth. Main gains are at idle and lower rpm. Smoother idle, a bit better economy, a little bit better throttle response, etc.

None, WOT on juice and off were not much, was a bit smoother graph but that is it. But as Ben and I posted earlier, under DD'ing conditions they make the car work better.

Gas mileage generally can improve with bigger gap, the spark is exposed to the mixture more, thus can ignite more mixture, thus more efficient burn. Now I need to do a side by side dyno gap test, but I can see it helping even on full load as long as you don't blow out.

how much did you enlarge the gap to see results?

On NA I generally gap coppers at .039-0.044 and just do a WOT run to make sure the spark is not breaking up (car will sputter if it is).

Is a copper plug the best?

Copper is the most conductive, but it's also the softest, thus doesn't last as long as platinum or iridium.