I developed a bad misfire during a road racing track event yesterday, and want to replace my plugs as the starting point for diagnosis of the issue.

Some facts:
1. The Check Engine light has not gone off (but I do have Perrin 02 sensor thingy for my test pipe... so I dunno if that matters).
2. The car has 29500 origninal miles all by me and I have never replaced the plugs.
3. I have already tried resetting the computer by removing power
4. The idle is very rough and there is definitely a bad misfire (or lack thereof).

My problem is I am not sure which plug I need.

Searching here I see everyone saying to use either the NGK BPR7EIX (iridium), or BPR7ES (copper) gapped at .024... or even less like down to .020.

However, the NGK America website, and my local Autozone are both saying I need part number IGR7A-G ^ #(OE Laser Iridium); Stock 3106; with .032 of gap.

Some people say gap Iridium’s some say don’t.

SO… what IS right? Please help me I need to get this resolved tomorrow.

 

go with what you found on here the BPR7ES have worked perfect for me.

 

Go with the ngk BPR7ES(part#2023). had no issue with them.

 

evo9 comes with the irridium stock. evo 8 comes with the coppers NGK BPR7ES. I believe that the Evo 9 have a longer thread length which makes them slightly cooler of a plug (I could be wrong). People gap them down to .20 to help with high boost and race gas or meth where they are suffering from spark blow out. How long have you been running your current plugs?

 

Autozone is wrong. If you want to stay with the copper plugs then the BPR7ES (stock) or BPR8ES (modded with increased boost) would be the proper plug for you. These don't last that long so you really should be changing them every ~15k miles. If you want to go with the longer lasting iridium plugs (~50k miles) which I recommend, then you can go with the BPR7EIX or BPR8EIX. Factory spec for spark plug gap is .020-.024". I recommend starting with .024" and going smaller if you detect any misfires. All the plugs I have recommended are for the Evo VIII and NOT the Evo IX.

 

So Kracka....... for the IX you use what?

 

I have the Denso IKH24 plugs in my IX, they're iridium and one heat range colder than stock. If you want to stick with the stock heat range then I recommend the NGK ILFR7H or Denso IKH22. Stock gap spec is the same as I mentioned above for the VIII's, but with my SpoolinUp COP I'm running .030-.031" gap.

My write-up: https://www.evolutionm.net/forums/se...h24-plugs.html

 

Thanks Kracka. I am also lookin at the Spoolin Up COP. Nice to know about the larger gap.

 

Hi all,
So I did get some of the NGK BPR7EIX’s gapped them at about .024 and put them in.
At first I was excited because when I pulled the second old plug I found that the little section of ceramic that coats the inner portion of the pug (surrounds the inner metal part) was cracked off and half of it was missing. Of course then I thought about how that might have affected the cylinder, turbo, and all the stuff downstream and started to think, uh-oh.
Then I got the other plugs out and unfortunately 3 of the 4 had the same issue. One of them had pretty much almost only 1/3rd of the original ceramic material left. I can hardly believe it even ran with 3 of the 4 plugs in this condition.
I created a pretty cool vacuum suction device using my Shop-Vac (6hp) and some tubing of various sizes so I could get a section of it down into the cylinders sucking. Unfortunately, I couldn’t get any material to come up out of them… so it has either passed though and done damage, or my MacGyver tool just isn’t going to work.
Anyway, I put the new plugs in and put it all back together, fired it up… and it’s still not right, so something else is indeed wrong. It’s a bit better than before (duh) but definitely still got issues. Sounds like a Subaru with big cams at idle.
So I guess I’ll have to get it into the shop… yikes!
Thanks again for all the quick help though… I appreciate it.

 

Take a pic of your coil and sparkplug setup and post it please. If it sounds like a subaru something isnt right with either the coil setup or a sensor. Gap should be at .020 for best results.

 

Old thread I realize, but it seems like nobody ever got to the bottom of what the difference was between the NGK BPR7EIX and the NGK IGR7A-G aka 3106. So I did.
And the answer is ... they are basically the same with very minor differences according to the spec sheets on their NGK websites: The only differences are:
https://www.ngk.com/product.aspx?zpid=9803 ...https://www.ngk.com/product.aspx?zpid=9492
NGK 3106 IGR7A-G Laser Iridium Plug ................ NGK 4055 BPR7EIX IX Iridium Plug
Terminal Type: Solid ..................................... Terminal Type: Removable Nut
Overall Height: ISO ........................................Overall Height: JIS <<<< not sure what the diff is here?
Gap: .028" (0.7mm) ................................... Gap: .031" (0.8mm)
Longevity: 100k Miles ................................... Longevity: 50k Miles
Ground Electrode - Material: Platinum ............. Ground Electrode - Material: Nickel
.................................................. .................... and the BPR7EIX also says: Ground Electrode - Shape: Taper Cut
so it looks like the 3106 / IGR7A-G is a slightly better plug.