Slo_crx1

Well ---- JD...hurry up and buy that camera I've never really seen much on tuning by plugs, and this is something I want/need to learn. The most I've ever gotten is black is too rich or oil burning, white is too lean, tan is good, but brown is better on boosted cars. :P I want to see color differences vs. AFR's type of thing, not just a generalization that most articels have.

Tom-Guy

I typically deal with fresh plugs, the ceramic is clean and any residues are very obvious.

Slo_crx1

I can understand that as far as detonation is concerned. I guess the best way for me to learn is to get a wideband and compare plugs to the afr reading. Obviously I would think the lighter the color the leaner the mixture. Next step would be to find an old straight back road and do a 3rd gear pull, shut the car off at the top of the run and pull over to see. It would be really nice to tune this basemap for a change now that my car is back in 1 piece

Tom-Guy

With pump gas I try for soot in the well, clean white ceramic, and a perfectly centered heat band on the bend of the ground strap. If your part throttle AFRs are correct then the soot in the well only comes from WOT, cars run pretty good.

If using racegas it can color the ceramic a little bit. Which brand and which octane for a given brand changes stuff around a bit. Torco 110 typically leaves ceramic looking like plug 12 in the NGK pamphlet posted above when everything is groovy, VP 116 burns clean but looks similar to plug 12 when you start to glaze it from too-rich WOT AFRs. VP 116 is also a trip, when you tear off the turbo manifold there is fine grey soot, not as thickly layered as the black gasoline soot.

I could talk all freaking day. I have to go look at a dyno with the BRMS boys, and then Pinks. More after the weekend.

iceracercrx

Plug reading is a great way of see what is happening in the hole. Widebands are great tool for getting it prefect. Use both and some dyno time you will be where she is running great.

Randy
PS We dynoed the motor that won the SCCA trans am championship in 1978 HAHAH It has been sitting for 25 years. It had a great air-fuel curve. We tried putting 2 more degree of timming in it, rattled. Those boys had plug reading down!!!

Slo_crx1

The more I pull my plugs out and look at the little changes I do to my fuel maps, the more small differences I'm starting to notice. I really wish my camera would take a good pic of them or I'd post them up to see. The wells have all the soot buildup, but the porcelin is still pretty clean (starting to turn almost an off white color now just because it actually seemed to run even better with a few percent more fuel than when I started) but the ground strap has a nice brown tint to it. I added a hair more fuel and it turned a hair darker, but it runs a bit better this way as well. I also ended up pulling out a few degrees of timing under wot full boost (even though it isn't detonating), just for the fact I noticed yesterday in 4th gear on the highway my temp guage started raising up a few degrees. Pulled a few degrees out, added a hair more fuel and now the temp gauge actually drops a hair (only about 5 degrees but I still thought it was strange).

Tom-Guy

Yup, exactly.

lkailburn

i was just looking at the spark plug chart :
http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

and comparing number 14 which is "the best" to number 17 which is still labeled as best im just so confused. at number 17 what are all the little flakes of light color material?

-Luke