ashb82

I think we need a thread about reading spark plugs. I go to the track a lot, I see a lot of the very fast V8 guys reading spark plugs after every single pass. So i thought i would go over and talk to some of the Pro Mod engine tuners about what they where doing. They are very helpful and seem very excited to tell what to look for. Also all the Pro Mod guys use EGT, wide-band and Data log as they make passes. I ask them if they dyno tune there cars the said they do. They also tell me that every track due to temps and altitude required different tunes and adjustments. I just think we need to look in to this it has really been helping me a lot to tune my car at the track. I have never put my car on a dyno but it runs really good from all that i have learned from the old timers. I know some of the tuners on HT have to be looking at the plugs and could take some pictures of what they have. I know there have to be some members that are interested in this.

Please post pictures, engine and conditions

SDHonda153

Here's a plug chart put out by Denso with some good general information about reading spark plugs...



Also a web page with a little more detailed information on it here

Linh.

Mine is looking like carbon fouling picture. Not sure whats wrong. Black soot is coming out my tail pipe also.

ashb82

I got this off of Dragstuff.com


Too lean and too hot, time to back some timing out of it and add some fuel. This plug has a blue tint to it due to the camara flash used, it didn't look that blue in regular light.



The above plug from a nice clean mid 9 second pass, this one was a little bit lean, added 1 psi fuel to it and picked up 3 mph. Note: Might need to take a bit of timing out of this tune up or use a colder plug, some deterioration on the center electrode however ground strap looked about right.



"Pepper" AKA Detonation. This was in a car that was running so rich that it blew black smoke out of it, but had too much timing. Note the center electrode is getting ate up a little and the ground strap has the look of metal that was heated up with a torch till it was bright red. The specks on the porcelain are supposed to be due to oil getting into the combustion chamber during detonation. This plug has been washed with brake cleaner, prior to that it had black soot everywhere.



Same car, next pass with 2 lbs LESS fuel, and two degrees less timing. The plug is running cooler now from less timing and is now coloring the porcelain. Now it's time to start backing down the fuel a bit more. This plug has been washed with brake cleaner, prior to that it had black soot everywhere.



Same car, next pass with 1/2 lbs LESS fuel, and same timing. Still see some peppering of the plug, probably getting some detonation. Still rich. Note: The rings were going away in this motor on this pass. We also burnt the clutches out of the TH400.



Here's an interesting one.. The above plug was in a cylinder that went "out", notice the gray down inside. The plug was working, then quit - fuel washed the soot off the rest of the plug. This is an Autolite racing plug, several plugs in this motor did this, the rest all looked gray on the base ring - perhaps a bit on the rich side but motor was running very good.

[img]http://www.dragstuff.com/techarticles/images/sparkplugs/jetxx20115ps016deg3.jpg[/imgl]

Ryan's Plugs AKA 66 283. Almost perfect fuel and timing, after this pull added 1-2 degrees more timing to take the heat in the ground strap just a bit more towards the corner bend and picked up 40rwhp.




Terry Wise sent these in, they are from his BBC, AR3933's a little rich, but real close.

ashb82

your to rich
takes some pics of them

Linh.

Ill do it this weekend and post some pics.

ef92b

here's a nice thread i came across sometime ago.

https://honda-tech.com/forums/forced-induction-16/spark-plug-gurus-please-help-me-diagnose-my-plugs-2084848/

ashb82

here are some pics as i was learning to tune with N2O and turbo i always use a wide band. I dont know if this is a myth or a fact but i was told at the track and read on some nitrous forums, that you watch your mph not et at the track to see if you are making more power as you tune.High mph more hp your making, it is working for me.




This is a 75 shot N20 plug is a ngk 2 step colder that stock plug. It has a signs of what I always thought looked to be detonation. this is why i stopped using n2o i never could seem to get rid of the detonation over a 75 shot with pump gas 93oct .
AFR where around 11:1




these are some plugs i fouled out after installing 880cc injectors






These are some plugs that i have been tuning daily driving with to work and back at 8psi
they are still running to rich mid to low 11:1 afr at full throttle from 5000 to 7000
from all that i have read the timing looks great because the way the strap changes color in the center of the radius. i dont see any detonation on the plugs.