Gernby

I'd like to know why you think a lean mixture puts more stress on the ignition system. It's not like the spark plug is going to draw more current when the mixutre is lean. The spark plug doesn't rely on the presense of gasoline to produce the spark, or to make the spark stronger.

I also don't understand why you think reduced gap is like advanced timing. When I increased my gap from .040" to .044", I started getting knock counts, so I had to retard timing a bit.

wadzii

when the gap is smaller the flame typically goes across the gap faster. It varies though, its just a rule of thumb.

Leaner mixtures can be harder to ignite than richer mixtures.

Gernby

The ignition spark travels at some fraction of the speed of light, and is unrelated to the distance it has to travel. If the distance is too far, then the spark just won't happen.

IIRC, the only reason for reducing gap is in the case of forced induction, where the pressurized air increases the insulative effects of the air between the electrodes (greater resistance).

wadzii

a tighter gap gives a longer spark duration, a wider gap does the opposite.

the longer duration is why it works better with a leaner mixture. The mixture at very lean AFR's tends to be inconsistent through the chamber, it can take a longer spark to fully ignite the fuel.

in some cases opening up the gap can increase the temp of the ground electrode, which is probably why you saw increased knock counts.

Gernby

I'll ponder on that, but it really sounds like you are going to give up power at WOT for the sake of fuel economy.

BTW, my knock counts went up with the .044" gap on a colder plug (BKR8E-11).

wadzii

I havnet ever noticed any real power differences on the dyno when closing the gap.

my car made 205hp on a pretty conservative reading dyno jet with just the aem ems

what plug were you running at 0.040?

it'S2klean

Thanks for the help guys, even though i wont lie, alot of that went over my head.
I have a high performance header and exhaust and the stock shocks just arent up to par top end.
So you guys would say that using the NGK-r instead of the NGK is putting the car at risk?
Ive also been reading a lot about how Denso Ik20's are really good.

wadzii

yes ngk r's are not the best for the car.

denso's have had issues with the porcelain breaking and falling into the engine.

it'S2klean

damn! I dont want any of that, so i will go with NGK, i hope my mechanic didnt already order R's. I can always replace em, wont run it to much with them in if thats what my friend got me.

Gernby

I ran the Denso IK24 at .040" for a couple thousand miles, then switched to NGK BK8RE-11 at .044". That is when I started getting a few knock counts.

BTW, IK20 would be way too hot for the S2000. Stock heat range is IK22, but IK24 would be better for a well tuned S2000 in a moderately warm climate.