I had someone tell me that when the straps on TR6's get a green stripe on them when spraying the mixture is about as good as it can get. I thought it was BS, but I pulled my plugs and I'll be damned if the straps aren't green!!

Is there any truth to this? Or was he BSing me?

 

Yeah, basically the coloration of the ground strap is just another indicator of the burn temperature.

Don't forget that heat is relative to time. A plug that can shed heat at a rate to survive 10 seconds on the bottle may not survive 15 seconds on the bottle at that same burn temperature.
It's also relative to the temperature the plugs are shedding heat into.

If you normally spray with a 170*F engine temp, but then one day you spray at a 220*F engine temp... things might not work out.

You have to keep these things in mind when you tune to the edge of part survivability.

 

Well, is it a good thing to be green or not? I understand what you are saying, but what about my straps? I don't want to be tuned to the edge. My air fuel looked great last I had it on the dyno, but straps were not green then, they were more black or dark brown. I always spray around 190-195*.

 

Green is good. Dyno doesnt put the same load on it, so its harder to run the right AFR on the rollers, which will be leaner on the street. If yours was black on the rollers, its probably right on the street. I tune on real loads just to avoid those type of confusion.

 

Thanks, that's the info. I was looking for.