My car was misfiring in the upper RPM's under full throttle N/A so I decided to pull the plugs out. I found the #7 plug with the tip broke off/missing . What would cause this? Should I be worried about the missing tip floating around in my heads?

 

MAybe it was broken when you put it in but it seems like you know what you are doing so i don't think so. The ones that were in my car when i got it, a few of em were missing a disclike think on the tip of the top. That really affected all of the gaps. I would just change it and see how things go, chances are its already through the heads.

 

did it look melted? Most likely it was severe detonation. You were close to total carnage. Btter either reduce the shot size or add some higher octnae fuel/reduce timing. Also be sure your fuel system is up to par and that is not the problem either.

 

I would definitely put that thing on a wideband.

It sounds like you blew it off to me also.

 

I thought it also was from detonation, but I never noticed anything out of the ordinary while spraying. My setup consists of an F1 kit jetted @150, stock injectors, GSS340 intank pump, Hotwire kit and TR6's gapped @ .035. All this is on 93 pump gas and 26 degrees of timing

Since i have a wet kit i shouldn't need bigger injectors so i take it that i should run racegas or drop my total timing down? or maybe it's time for a direct port setup since i've read about the back cylinders not being reached using a nozzle kit.

 

I think either reduce timing a bit or run a little race gas. Maybe even a bit of both.

 

Did you just burn the ground strap off or did you crack the insulator and or hurt the electrode? Was the insulator all speckled? I would get the car on the wideband first. Seeing as it was number 7 you probrably have a lean condtion in 7 & 8 due to fuel distribution. With the stock TNT 150 jetting, my car had always run alittle on the lean side and would occationally burn acouple of ground straps. I stepped up the fuel alittle and things became fine. I would pull alittle more timing too, don't forget that the TNT 150 shot is like a 175+ at the crank. The most timing I can get away with on the 150 shot with 94 octane is about 24* before I start to see some KR. I usually shoot for an 11.5 A/F ratio. The car was at about 12.2-12.5 across the board when it would start to melt the ground straps.

 

about half of the ground strap was melted off and a small chunk of the insulator was broke off, but the electrode was still completely intact. There was no speckling that i could see.

Would it be better to reduce timing/add more octane or to up the fuel jetting on the kit?

 

Do your have anyway of looking at KR or are you tuning with no knock sensors? Any time I have gotten a good amount of detonation there would be small specs of what I assume is from the pistons on the insulators. Seeing that it's number 7 and the insulator is still clean I would guess it's more of a fuel problem. I would really spend the money to get to a wideband or even buy one (best tool I ever bought). I supose you could pick up a pair of 26 & 27 fuel jets and just kind of do some trial and error tuning.

BTW: TNT doesn't sell .026 & .027 fuel jets so I use NX fuel jets instead.

 

I'd say you might want back the timing off to about 22 degrees and you should be good.

 

I say pull the TR6's out and throw them as far as your arms can throw them. Use a non-projected tip spark plug a few heat ranges cooler then stock...Like a Ngk 7 or 8 and also go up a pill size or 2 on the fuel side. Just my thoughts.