Is it true a tighter gap you start to notice power loss as opposed to a wider gap? Mods are in sig, currently running ngk bpr7es gapped at .026 and the car studders a bit

 

I had the same issue, gapped at .026 and was missing at higher rpm. Gapped it down to about .022 - .024 and its been fine since

Tighter gap is a weak spark and wouldnt ignite the fuel properly opposed to a wider gap with bigger spark but, imo, it all depends on the tune.

 

Then how come I see more people running a tight gap? I'm thinking dropping to .022

 

people run tighter gaps to prevent spark blowout which is what the missing he described is. Its done when running higher boost levels. Power does decrease with a tighter gap. If you want to run less gap i suggest upgrading to a coil on plug setup or upgrading the ignition however you would like. The more gap you can get away with the better mpg, power, and idle will be better.

 

/\/\/\ This

 

I'm running .026 on stock plugs with a COP setup. 23lbs, no issues. but i'm only making 340 whp

 

I was running .028" with my spoolinup kit no issues. I played around with gaps and didn't find much of a difference other than the larger I went the better mpg. Basically, the idea is to run the largest gap you can get away with.

 

Air is an insulator. The more boost the more air which may impede spark. You either need to narrow the gap at high boost or increase the spark voltage. High voltage requires a high quality ignition system.

 

I just find it weird that on a stock turbo, im having trouble with what a normal gap is .025 I don't even run high boost. 18psi tops.

 

stock gap is .020-.024

 

my manual says "Standard value: 0.7 − 0.8 mm (0.028 − 0.031 inch)" but that's for an iridium plug. .025 with that plug at that boost level shouldn't be a problem, you may want to check your coils and wires.

 

My gap is at .032 and I'm not having any issues. But I am also completely stock.

 

It has to be my coils n wires. Im gonna just dump it for a COP setup.

 

Save your money it could be something as simple a bad plug. Try closing the gap to 22 like you said and if that doesn't fix it check your coils and wires.

 

Run the widest gap your setup will allow, within reason of course. Each setup will differ but if it breaks up close the gap. I have ran coppers down to 17 and now run iridiums at .22 without issue.