i read unabombers faq, but i still have a question it says in there that if they are pre-gapped they are not intended to have the gap changed by the end user, so i'ts about time i need a set of one step colder and a guy on here has some ngk iridium one step colder and he says they are pre gapped at .44, so i was wondering if i shouldnt buy these becuase they are already pre gapped? or if i can change the gap

You [i]can[i] gap iridium plags, but you best leave it up to someone who knows the theory of gapping iridium plugs. .44 is NOT good, so they would have to be gapped by someone who knows what they are doing. The reason you need a pro is that if you mess them up, you will ruin the iridium plug as teh tip is so, so small.

Gapping ANY plug down from .044(-11) to ~.030 for a WRX is a bad idea.....and it is REAL-REAL easy to make a good $11 plug into a paperweight in a blink.

Get the correct plug to start with, the NON -11 plug ;), and go from there.

I had to decrease the gap on my autolite plugs. They were up in the .40 range out of the box (even though the guy at autozone said they were pregapped to .30). I just tapped em down a little bit and gapped them to .30. Ive had em in for about 300 miles and it runs like a champ. I donno, maybe i just got lucky.

AirForge,
Their regapping dicussion only pertains to the iradium plugs. But it has been my many years of experience that the correct plug is usually pretty close outta the box.
regards,
Steve

An NGK sparkplug that has a '-11' at the end of the number is pre-gapped at 1.1mm or .0433" That is the WRONG plug because the SAME plug WITHOUT the '-11' is pre-gapped at .7-.8mm or .0275-.0314" which is the CORRECT plug to start with, for a WRX.

This IS on NGK's website...

no matter the plug type, you shouldn't gap < or > .008". The reason for this is the ground electrode and center electrode won't line up properly, hindering spark plug performance.

The manufacturers say you should not gap iridium plugs. This is because most people do not know how to properly gap a spark plug, and the center electrodes on the ultra-fine iridium can easily snap if mishandled. There is no warranty for snapped center electrodes. The manufacturers say an iridium spark plug will run so much better than a traditional plug, even if it is not gapped for that motor, that they would prefer you just leave it rather than risk snapping the center electrode.

Here's instructions on properly gapping:
"If it iss necessary to widen the gap, do so with a tool that only pulls back on the ground electrode without touching the center electrode or the porcelain. To close the gap on a plug, gently tap the plug, electrode first on a hard surface." (taken from sparkplugs.com's "sparkplug 411" page)

Scotty's 100% correct on the "-11". Start with the non"-11" plug and this will minimize or eliminate the amount you will need to gap.

Sorry for the mis-understanding .. but what is the correct gap for 2.5NA???

Sorry for the mis-understanding .. but what is the correct gap for 2.5NA???


for the NA, 2.5, SOHC, according to the FSM, .039" - .043"

So the '-11' plug is the CORRECT plug for the NA, SOHC, 2.5 ;)

Kong :devil:

Kong :devil:



....it's FASTER now :devil: :banana: :lol: