8's all the way

 

The NGK BR8EIX is a really nice plug. I get a super smooth powerband with them gapped at .027

 

Isnt .027 a little high on stock ignition?

 

The stock plugs call for a gap around .029-.033 if I remember correctly so considering you're just going one step colder and keeping an iridium plug with the BR8EIX I see no problem with .027. It's always worked very well in my Evo.

 

So what should I gap them at? I really hope this solves the problem.

 

Go with the 8s and I gap mine to .026.

 

K, i'll probally pick them up tomorrow.

 

I got the 7 equivalent (BR7EIX) and I will never use copper NGK's ever again. Spraying W/M on them at 25 psi gapped to 0.025 with stock coils and haven't had any misfires, fouling, or whatnot.

Have you checked your afrs lately?

 

Not saying this is the problem on your car for sure but I had the same problem and it was my BOV. It wasn't closing fast enough / lagging open and would cause rich spikes and backfire right when getting on the gas after a shift.

Swapped the plugs, swapped wires, still there. Swapped BOV, went away.

 

Would a stiffer spring close it faster? I'm going to check for the exhaust leak first, then change plugs, then mess around for a boost leak and such. Hopefully i'll find a tactrix cable so I can get some logs aswell.

 

Ok so I re-gapped my plugs down to .22-.23 and now the car doesn't backfire at 7k anymore, only when I shift at 7.5k.

 

If you replace your wires and your coil boots you will most likely be able to retain the higher plug gap and the benefits of the hotter spark.

 

Right now I put in new BPR7ES with a .23ish gap. I also tried to put the stock BOV back on just to see, still did it.

 

that gap size is pretty small try 26

 

ya .26 is real nice.