Help Me Read These Plugs
 

The pics are Autolite 103's I had in my cam only LS3. I used them in my old high compression LS1 build but I think they're too cold for this setup (they're same as TR6's) I switched to Champion Copper 408's which are stock heat range plugs for an LS3. So do the plugs look too cold for you guys as well? The plugs were on the car about 1500 miles since I put the motor together. Ive since adjusted the timing (less of it, 28* wot) and fuel, 12.8-13.0afr wot. I don't drive long distances and I think the cooler weather as well made it worse, cold plugs couldn't burn off all the carbon.

Some info,
LS3, stock block and heads
TSP 231/236 114lsa
LS1 coils with Taylor 8.5mm LS3 plug wires

I was seeing 28* timing at wot so I know the ecu wasnt pulling any timing and I didnt see any knock retard either. No blowby, doesnt use oil and oil looks clean. Plugs were dry also when I pulled them.

Many pictures on those type of charts are either vague, low resolution so you cant see, or extreme cases. The ones in the link posted are a bit better. I just wanted to see if others agreed that they seem like plugs that were too cold for the motor. Also think the orange brownish color is from running octane booster at the track.

They look normal to me. What fuel are you running? This is one of the plugs I pulled from the Cobra with about 5,000 miles on them.

It's too hard to tell the heat range with that many miles on them. Put a new set in make a quick pass and them inspect them. The red/brown color is why I asked about the fuel. The additive would be the cause.

Use NGKs this time, heard too many horror stories with Autolites.

I used an octane booster before i fine tuned the car. I think that caused the orange color. Car only sees 91 now, mostly chevron. Ill do a quck wot run with the new plugs and then check them out.

Thats all ive ever used with no issues. Theyve always looked like new after months of driving. We will see with the champions now.

I see red, what kinda fuel additives are you running?

I ran NOS octane booster. The stuff does work a bit.

I have always run standard Autolites in everything and never had an issue.

Hate to break your heart but it prob doesnt. The main ingredients in that pint of octane booster are Toluene or Xylene? I think it is. And you need 1 gallon straight of each, to raise ten gallons of 91 octane to 94 octane. So a pint aint gonna do shit, haha.

Go to your local paint supply store and pick up a 5 gallon drum of Toluene.

And ya, additives prob caused the red, or I think rust might do it too... but I doubt you have that problem in a C5

Mix E85 in there or run Torco if you need the extra octane. Im using E85 now to get me around 94-95 octane. Gonna go with Torco to make things easier. Torco does work, seen it with my own eyes on the dyno.

I've run a can of Torco at Adams to keep the Cobra from detonating and it works great.

I have no need right now for the extra octane. I used to use a gallon of xylene before for my high compression motor but its $15gal now. So then I started using a mix of 30% e85 with 70% 91 for a few years and it worked great. When I used the nos it was two bottles for 1/4 tank of gas. I know its not great stuff but I have seen it work to a point. Here in CA its the only one off the shelf that might do something but you need two bottles at least. Also Im only talking about it helping for 1* or less of kr I was seeing. Not like it boost octane enough to to add timing or boost or something like that.

It has a small amount of nitro methane. I think it raised 10gal up to 92 from 91 in a test. I know, not much.

Btw this was just once, that i used octane booster, when i put the ls3 together since the old tune had too much timing in it, like 34*, but i ran cold plugs and the e85 mix. When I did try octane boosters before, they never discolored my plugs. I think the fact that the plugs werent hot enough kind of let that stuff bake on the plug this time.

Took a short drive, gave it a quick wot here n there. Now the ground straps are all white. Wtf? Porcelain is clean, no specks.





The car is a bit lean while cruising but wot is still 12.8. Crappy fuel?

Torco works. It also works out to be slightly cheaper than Toluene IF you buy it in 5gal pales (for like $250 AIR). Takes maybe about a quart to do the same thing 1.5-2.0 gallons of Tolune would do in my 15gal gas tank.

My neighbor is a Torco distributor, said a case of torco costs about $100

How bout my new plugs and how they look?....

Are you using stock heat range plugs? What plug gap? I ran .044 in the GTO with TR5 plugs and it ran good.

I believe the gap is .45, stock heat range. I wonder if i got bad gas or winter blend extra ethanol. Wierd.

I know a guy that sells it for $120 for a case. Gonna get a case of it then get a 5 or 10 gallon drum (however big they are) and just refill the cans.

The heat range of the plug is too hot. Go one step colder and test it again.

Then im back to what i had. Lol. Ahhhh!

See how the entire ground strap is the same color? That is a sign that it is too hot. It should change color around halfway. If it changes near the tip it is too cold.

Ill try ngk tr6's next. Tr5 is stock, tr55 is same but with a .55 gap. Tr6 is a step colder with a .35 gap.

Could it be that my old spark plugs were ok, heat range wise, but the octane booster that was still in the tank when I first ran the motor turned them orange? And...now the new stock heat range plugs are too hot?

Well, I figured the car ran good all this time with the colder plugs so i put some tr6's on there. Gonna drive it a bit and see how they look. If it stil looks like theyre cold Ill put the champions back on. All I know is I shouldnt see any more rust colored deposits on it.

This is possible.

As I understand from chestry, no way. Nitro Methane does not mix with gasoline.

But Nitro propane does. It's a fantastic way to blow the holy fuck out of your engine!

How many quarts in a case? A 5 gallon pale (20 quarts) is about $250 last time I bought.

I think 16?

Better to run AV gas mix. Its about .90 a gallon, and is something around 130 octane. A 10/90 split would be perfect to considerably bump a tank of fuel.

I'd have to check my garage, but I think it's 8 (if it's the same I got years ago.) The beauty of Torco is small amounts bump the octane a fair bit. Like I said, I was getting about the same results from one quart as I was getting from nearly two gallons of Toluene.

I think white means too hot or coolant fouled??

Well guys heres what I found....first all the whitish color is from the plating on the tip. The nickel coating gives it that color. I hadnt seen that before with my autolites because they have a black coating, not nickel. What I did go off was the color band you can see on the ground strap. With the stock heat range they were close to the base, indicating it was on the hot side. With the ngk tr6's, the mark is now closer to the middle of the strap indicating a proper heat range. I noticed the car idles very well with the ngk's and seems to rev up smoother. Also less exhaust popping on decel. Only thing now is, I did a 3rd gear wot test on the fwy today while data logging. I figured it was warm and if I would see any detonation it would be then. I got no knock and the car felt great BUT the timing at wot was 31.9* when I had tuned it at 28*. Idk why it would jump like that. Would the ecu advance the timing? Or maybe a timing table is different if im manually in 3rd? (4L65E 4spd auto). Wierd.

AIR, the LS ECU will "trim" timing +-. Basically, it says something like, "mmm, no knock and not too lean? well then turn it up man!"