yes and makes the plug a little cooler.

I run br7es and bpr8es

 

Add me to the Nils/KingKyle list.

jeff

 

Nonprotruding plugs pull the electrode back out closer to the plug itself and out of the cylinder wall. I gap my bpr8es's at .027-.029 depending on what I feel like

 

Bought my car 2 weeks ago with 16k miles on it. First thing I noticed was a slight misfire at higher (>4k) RPMs. Replaced plugs with NGK 7's today and it's smooth sailing all the way to 7k now. woot. The car had the stock iridiums in it when I got it BTW.

 

The iridiums can be misleading. They can look fine but perform terribly. One time while on the dyno, we had taken the stock plugs out that looked perfect, but replaced them on principle because they had about 17k with many track miles on them. The car picked up 15 HP with that one change. We were very surprised and now we're very concientious about changing plugs regularly.
When you can see physical degradation with the iridium plugs, it's way past their prime.

We change them out at approx. 8k for all the EVO race cars and at approx. 15k for the street cars.

With NGKs, the higher the number, the colder the plug. DSM 4G63s came with a heat range of 6.

 

I change my Iridiums (stock heat range) at the beginning of each season and have never had a problem, using the car as a daily driver and doing about 8 autocrosses and about 8 track days during the season. That averages out to about 8k miles/yr. The car idles a bit better after the change for the first week or so, but then it's pretty much back to the same after that. I tried the coppers once - the car ran much rougher. I checked the gaps and they were all within recommended range, but still ran like crap so I went right back to the Iridiums. Last time I found the Iridiums (NGK BPR7EIX) I picked them up on Amazon.com (yes, Amazon) for about $20/set. They have them for about $32/set now.

I've heard of guys having problems with plugs fouling if running a colder plug on the street - they supposedly foul quickly unless you're on the turbo all the time. Has anyone else found this to be true?

 

I picked up few tenth of a sec on 0-60 (measured from G-tech) by changing the OEM plug to new plug. The car runs much smoother than before.
I am very surprised it make that much difference.

 

again, i go for the el- cheapo's.

swap them out, id say every oil change, which depending on track usage is possibly 1 event, but normally 2, and up to 3. (if i ran in the wet.)

 

Going more than 3 or 4 track days on the same plugs is asking for trouble. Big trouble. They cost like $2 apiece. Change 'em often.

 

what about a car with my mods just ragged on the streets.. probably 330-350whp idk trapping 114 in 90 degree humide florida weather... i have 17k (purchased new in december) i planned on changing at 25-30k is that okay... ive owned high performance cars be4 and never changed them til there was a problem and that was at 59k in my previous audi.. and that was a 290 whp car 140 stock... on stock plugs...

 

every 15K

 

+1 for me.

I have around 47K miles on the Evo ... which sees basically a 50:50 mix of street and track use. The car is tuned fairly rich. Changed the plugs for the very first time at 45K miles. The original plugs "looked" fine.

I swapped on a set of OEM Mitsu plugs. Following the swap, I observed no noticable difference in performance or smoothness. So, I'm not sure I buy into the whole "change your plugs every Monday morning" logic.

Emre

 

still on the stockers here, 47k about 6k worth of 100% meth inj. with a few road race days in there too.

 

I had a plug come apart on my Eclipse - not a pretty sight. Ruined a new custom JE piston when the insulator came apart and bounced around between the piston and the head, before exiting through the turbo. cheap insurance to change them, especially if you've already changed to copper plugs, and/or have mods.

 

What exactly is the advantage of copper plugs? I run them in my BMW race car, as that's what's recommended by BMW and my engine builder. But I thought the 4G63T in our Evo was designed to run with iridium plugs. How is switching to copper any better?

Emre