Porcelain white but AFR shows 12.5-12.8 at WOT??

[5.3LS10]

Quick question. I pulled a couple plugs the other day just to see how everything is looking since I am still learning and realized the porcelain part of the plugs are very white. I am at work right now so cannot upload datalog until this evening but the datalog from the track wednesday night showed 12.5-12.8 pretty consistently. These are pics of all 4 plugs on the drive side of engine where the O2 sensor is. I still need to get the car dyno tuned at WOT but want to make sure everything is looking good so far before I put forward the money to have it done.

I will upload tune and datalog tonight.

Engine is a freshly rebuilt (~400 miles) 6.0L LS with a cam and LS3 top end.

would you agree plugs are whiter than they should be?

Thanks
Shane

[nathaninwa]

Is this on E85?

[5.3LS10]

Is this on E85?

lol that must not be good if you are asking that.

Just 91/93 octane.

[nathaninwa]

It would be a good thing. My plugs at 11.5 are white

What wide band are you using?

[5.3LS10]

It would be a good thing. My plugs at 11.5 are white

What wide band are you using?

Is that with E85? I would have thought gasoline would give the usual tan color. Its a Bosch LSU 4.2 innovate LC-2

[nathaninwa]

I should correct that. I was commenting on your good thing using the e85 and the white porcelains. You should have tannish plugs

Does your widebands gauge match TS?

I used a system with no Gauge,just the controller one time and went through the proper setup and compared to my Aem as a backup, the Aem read 15.0 while the controller setup which ran the car read 12.8

Proved it on the dyno and made almost 40whp by running the proper afr from the Aem

[5.3LS10]

I should correct that. I was commenting on your good thing using the e85 and the white porcelains. You should have tannish plugs

Does your widebands gauge match TS?

I used a system with no Gauge,just the controller one time and went through the proper setup and compared to my Aem as a backup, the Aem read 15.0 while the controller setup which ran the car read 12.8

Proved it on the dyno and made almost 40whp by running the proper afr from the Aem

Unfortunately the gauge stopped working over winter and is pretty low on my list right now. I have just been using the gauge in tuner studio. I have another wideband sitting in a box (14point7 diy WB). I can add it to the other side of the engine and monitor that one.

[nathaninwa]

Try it and see. I was running twin Spartans on my all motor LS and they read within .1 afr of each other, but it was those same widebands that read lean compared to my Aem and dyno's wieeband. There no longer on my car

[benckj]

I was over a 1% different between my LC2 gauge and TS until I selected generic O2 setting and used a lower cal reading of 6.3. After that the gauge and TS agreed plus it was confirmed by Tuner when car was on dyno. He indicated that different cal values are used with his set-up as well.

Jim

[5.3LS10]

I was over a 1% different between my LC2 gauge and TS until I selected generic O2 setting and used a lower cal reading of 6.3. After that the gauge and TS agreed plus it was confirmed by Tuner when car was on dyno. He indicated that different cal values are used with his set-up as well.

Jim

I just looked up the manual and it says 7.35. I can try lowering it. that would explain that it is actually leaner than what it is displaying.

[5.3LS10]

Here is the current tune and a datalog from the track. Actually looks leaner than I thought

[kaeman]

Where did you check the plugs, at the end of the pass or after driving back to the pits?
As I understand trying to read plugs, you have to kill the engine after your pass, coast into the return lane and then pull the plugs or get towed back to the pits and pull the plugs, I have been told that the drive back down the return road will make all the plug readings wrong. When you check the porcelain, you look down into the base of the porcelain inside the threaded portion of the plug, not the tip of the porcelain.

[Yves]

the wot colouring is, if i'm not mistaken, at the base of the porcelain.

BTW : yours show traces of detonation (black specks)

[5.3LS10]

I will shine a light down inside the plugs and see what I can see.

Also I just noticed I got my 2 AFR lines messed up. I was looking at AFR target and not AFR. The datalog 21.03.21 shows 13.5+ at WOT.

I do the little black specs. I did not realize that was detonation. I will pull a degree of timing out for now until I can get it to the dyno.

I am also going to increase my VE cells from 4000-7000rpm at WOT.

[DaveEFI]

Personally, I'd use a decent wideband O2 system rather than the ancient way of trying to read a plug colour.

[turbo conversion]

There is a big difference in AFR between the first and the second data logs, what if anything did you change?

The first log is consistently lean while the second log is much closer to target.

David

EDIT: what is your shift rpm target?

[nathaninwa]

This is a plug from the last trip last year to the dyno. 12.8ish afr at 25* best power. Made final pull, idled on trailer and into garage

TR6IX plug

[turbo conversion]

One thing I noticed in your pictures is a lot of anti seize on the plugs.

According to NGK they say do not use anti seize on their plugs, they are treated so it is not needed.

The reason for this they say is the anti seize will alter the heat transfer affect of the plug.

Something else I noticed is the center electrode looks odd, kind of mushroomed.

David

[dontz125]

Where did you check the plugs, at the end of the pass or after driving back to the pits?
As I understand trying to read plugs, you have to kill the engine after your pass, coast into the return lane and then pull the plugs or get towed back to the pits and pull the plugs, I have been told that the drive back down the return road will make all the plug readings wrong. When you check the porcelain, you look down into the base of the porcelain inside the threaded portion of the plug, not the tip of the porcelain.

This. There's a reason it's called a "plug chop", because you chop the engine dead from WFO. Idling back (especially on a 2-stroke race bike!) completely masks the reading you're trying to get. And yes, you're looking for the burned ring deep inside the plug. The Wise Old Tuners had special scopes to get a good look in there. Also, the plugs have to be pretty darn clean for each pass - 100hr plugs caked with crud are useless for reading a chop.

Personally, I'd use a decent wideband O2 system rather than the ancient way of trying to read a plug colour.

Absolutely - much easier, and much quicker. And when your O2 logs don't match your O2 gauge, or what the engine is doing - then what?

I agree with the comment about the electrode - it's not supposed to look like you've bee doing arc welding inside your engine!

[Yves]

The tip is the result of overheating either because of pre-ignition or detonation. These 2 phenomena go hand in hand.
The op is in a dangerous zone and seriously needs to take a good look at things

Edit : when thinking about this more and assuming the black specks are all that is to be found, no alu speks, i think pre-ignition occured first.