I know there are a lot of threads on here about how much to gap your plugs but I have a somewhat different question.

I'm currently running NGK 7's (stock heat range) gapped to .028 which is how they come straight out of the box. My understanding is that the greater your plug gap is, the better the spark will be, which will result in a better burn and more power. Also for max power you should increase your gap until you get misfires at your boost level then close it up a bit.

My question is this; is there a point of deminishing returns for plug gap? Most people with basic mods like me (TBE & MBC) run a .026 gap on the stock ignition. I'm not getting any misfires @ .028 so should I try and open it up?

 

Kind of a rough table to shed some info on it (I'm not claiming I know anything but it's likely right)

7's - no more than .028 at 21 - 22 psi
8's - no more than .026 at 21 - 22 psi
7's - no more than .025 at 24 - 26 psi
8's - no more than .023 at 24 - 26 psi

With OEM ignition system in good condition

 

what about with the hks dli2, alcohol and or race gas and an upgraded turbo like the 3065?

 

/\ good info

evoisdream

 

Test and Tune?

 

haha I just noticed I spelled question wrong...

anyway, to update this post I am still running .028 gap on the stock ignition with about 22-23psi of boost. @ WOT everything seems fine, no misfires, but at idle I'm getting misfires like a son-o-b!tch. The RPM is bouncing up and down while the A/F dips and dives between 13.0-15.5:1. I bought another set of plugs and gapped them down to .025. I'm installing them tonight and heading to the track tomorrow. Hopefully it cures the misfire @ idle problem and I don't lose any power at the track.

 

i am having a similar problem.....I just installed the BPR7eix NGK's and at idle it will fall sometime to like 500-600 and stumble...have them gapped from stock setting at .30 not getting any misfire codes though

 

^^ It's lame you can't set the gap in the irridiums. I don't see why people buy them. Mine were toast way before 60K miles and they cost a lot too...copper is the way to go IMHO...