I bought some ngk irridium spark plugs and I want to know what should I gap them at

 

They should be pre gapped for your application when you get them..........they are very, very hard to regap without breaking them.

Dusty

 

Yea they do come pre gapped, but it really depends on your boost level, if your higher then stock then you need to close the gap a bit, I am running about 10 psi spike to 15 on and I gapped mine to .040, factory is what .050 or something, when I left mine stock I miss fired due to higher boost lowered the gap now it runs fine. Liek Dusty said be careful they can break

 

If you do regap them or any plugs for that matter you'll want a wire gap gauge, the gradualdisc gap gauges are no good if you want a precise measurement.

 

If you bought the NGK 4306's they do not come pregapped...

 

I have mine gapped at .045.

 

irridiums and coppers are not gapped at the same levels. leave the irridiums alone, just check that they are all gapped the same. if you start getting blow out then adjust, but usually the irridiums are fine.

 

 

again....THESE ARE NOT COPPERS. irridiums need a larger gap than coppers do. on a stock car irridiums work perfectly well at .050-.052.

 

I just saw ngk and started typing... i'll take my foot out of my mouth now.