Plug is an NGK 8 heat range, pump 93,50/50 water meth and 19.5 PSI. Plug has a few pulls and ... some cruising on it also.

What I can't seem to figure out is the black soot on the base ring and porcelain . Targeting 15.o afr at light throttle cruise.

Overall what do you guys think?

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I'll add that tomorrow I'm going to experiment with decel fuel cut off to see if that has an effect on it.

 

My experience with DFCO is that its a driveability tool more than anything. If your getting backfiring through exhaust at decel or tip in response issues this could be the culprit.

 

Looks like timing too low to me.

 

Not having any running issues, I was thinking that the soot might be from closed throttle decel when the afr swings rich before CL can catch it. ? Figure it's worth a try.

Based on? Ground strap? Not arguing,looking for info. I'd like to try more timing but figured I'd clean up the afr first. As I've been working my way through higher boost levels,I got into some detonation, so keeping it safe,I think,for now.
At 19PSI I'm targeting 12.0 and 15 degrees. Was at 11.7 and the "fuel ring" at the base of the porcelain was much darker/wider.

 

Based on the color of the porcelain and ground strap. Hard to tell if your WOT timing from this plug since it looks like it has some run time on it.

 

When trying to read fuel marks on a plug you can’t have “a few runs” on them.

You need to install a new set with VERY minimal idle/cruise run time. Then go WOT and shut the engine down immediately and pull them. Anything else will muddy up the readings. If you have a WB02 jut read the heat markings on the ground strap and threads for timing. Spray them down whit brake clean to get a cleaner indication.

I basically look to what I feel is the hottest plug going by the heat markings. Then swap that plug out alone when tuning. You want a clear indication of the CAD plating burnt about half way down the strap for a “safe” tune IMO. Not into the bend and not past the 2nd thread.

This is an aggressive “race” tune up IMO. Good tune, but very close to the edge. On a street setup I’d back this tune down 2-3* at least.


Good luck!

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