Ok brief history of the car and plugs first. Bought the car with the Comptech SC w/AC installed, everything stock except OEM mufflers replaced with magnaflow units, just the mufflers.

Dyno'd the car and it was misfiring near redline, turns out the previous owner was running OEM plugs at OEM gap.

I replaced those with the 6097's that were gapped at .035 re-dyno'd and everything looked fine after adding a few lbs of fuel pressure. Since I was going to be doing some long distance driving I swapped them out with the 2668's (BKR8EIX) after 2800 miles. They looked fine for the most part when they came out.

Today I replaced the 2668's with a new set of 2668's since I'm going to re-dyno on Monday. I didnt know when I re-dyno'd that the 6097's were the stock heat range and I've also replaced the B&M fuel pressure gauge with a Summit liquid filled that now shows about 6+ lbs of fuel pressure then the B&M showed.

Here's the 2668's that just came out of the car, cylinder #1 is the one that concerns me, small white spots on the tip, the rest of the plugs looked fine to me.

2668 #1



#2


#3


#4


6097 #1



#2


#3


#4


Anyone see anything alarming here? I guess I'll find out how I'm doing on the Monday when I hit the dyno again but odd that cyl #1 looked different then the rest of the plugs in the group. Any specific reasons that could happen?

BTW I reduced the gap on the replacement 2668's down to .032 from .035, seems that a lot of people run them at the stock gap of .030 so I figured middle ground would be ok.

 

Can you tell me how many miles did you put on the 2668's that you've pictured?

If it was just WOT dyno pulls, then you're getting full throttle detonation and/or lean condition on #1.

If these plugs had miles on them from daily driving then your experiencing part throttle detonation and/or lean condition

If you ever get a chance to look at the #1 runner in the intake manifold, you see that its the only runner than is positioned almost directly in the flow path of the t/b opening. This may be why #1 is leaner than the others.

With certain engine managements, you can increase the duty cylcle of a single injector to compensate. Not sure what managment you're running but if you're on the stock piggyback, I'd bump the fuel pressure up another 5psi and go to a load bearing dyno that can provide part throttle and full throttle tuning.

Good luck!

 

BlackTrax is right. The shiny balls on the first plugs picture are aluminum from your pistons or head. Det vaporizes it, and the plug is the usual place it collects. Those are big. Usually you need a magnifying glass.

 

Approx 7200 miles on the 2668's, about 70% highway miles and the rest round town.

 

Then I would say that your having part throttle detonation issues. Check the wiring on the piggyback unit then do some part throttle dyno pulls and check your afr's. Also have someone listen for audible knock.

 

ESM wiring looks ok but I'm going to pull it apart and check it better over the weekend. The AFR was right on point, the worst of the 3 pulls was hitting 12.5 around 6500 and then coming back down to just under 12 at redline. The other two pulls looked almost similar and finished around 12-11.8. The mechanic doing the pulls had another one of the guys in the shop come out and listen for detonation and we didnt hear anything at all.

The guy that runs the shop said the plugs didnt look like they were showing signs of detonation. He wasnt sure what the specs on them were but he said he had seen enough plugs from cars that were detonating to know it when he saw it. His first and most urgent suggestion was to lose the iridiums and go back to copper (which I had already done).

I'm going to run the car normally for the next couple of weeks and pull the plugs to take a look again.

 

My tuner told me that you should run all dyno runs and tuning on the same exact type, gap, and heat range plugs, changing/switching to a different gap/type/etc is not advisable, since plugs make that big of a difference.

 

If there's not an issue and you're using the proper plug at the proper gap I could understand that but that wasnt the case for me. I wasnt dyno-ing for hp purposes but for safety purposes and to try and see if I was detonating and if so why.

 

I was sure that at WOT you're fine. It's at part throttle that you need help on. In my first post I mentioned a load bearing dyno that can handle part throttle tuning such as a Dynapack. This feature allows you to simulate part throttle driving.

Also, in my experience, iridiums produce more power on coil on plug motors such as ours. However, we do use coppers on race cars because we index, inspect and change them every race plus they're 1/3 the price of an iridum.

 

I'll look into finding a place that had a dynapack for part throttle AFR. I ran my tank down to almost nothing last night and filled up at a different gas station just to see if maybe I was getting some bad gas at the local Mobil (which is very ghetto).

Why would I get part throttle detonation, what would be the causes of that with a stock CTSC kit? I'm doing some investigating into a 7psi pulley and greddy emanage which would solve that because I would have the emanage tuned by a reputable shop. I'm just not sure if I should bother with injectors or leave it be with the OEM ones.