Reading spark plug.

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R68DartGT

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Hi, I just took this out after about 100 miles. Looking for opinions on how it looks, rich, lean ,etc. The fuel is 91 octane with lucas octane boost. Appreciate any feedback.
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I don't think I have ever seen the picture perfect spark plug shown in the manuals. You look good.
 
Rat Bastid said:
Why are you running the octane booster? leave it out and run the plugs some more.
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This came out of an indy cylinder head engine and they recommended 93 octane. Problem is in my neck of the woods we only sell 91 octane. It'll spark knock with out it.
 
So it has only been 100 miles but when I look at my Champion spark plug decal on my tool box (see below) it looks like perhaps fuel or oil additive ash. So I found the picture of the decal and posted it below but I noticed after I posted it that this one has the same pictures but it says leaky valve seals instead of additives, for the same identical picture...I would not agree with that at all. I'll leave the pictures below just so you can see that it is probably the closest to yours with the tan coating but I would not jump to valve seals. To me I would pull them after more miles and see if it stays the same and if so it looks good to me.
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R68DartGT said:
This came out of an indy cylinder head engine and they recommended 93 octane. Problem is in my neck of the woods we only sell 91 octane. It'll spark knock with out it.
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Ok, I doubt that Lucas is actually raising the octane two FULL POINTS. It may raise it .2 points but not 2 points. Very few octane boosters will raise octane 2 points.

There is far more to fuel than octane rating. I think you should reduce the Lucas octane booster by half (half of how many ounces per gallon you are now using) and work on your tune up.

Adding all that booster is IMO a waste of money. I’d have to see the rest of what your build is, but I think you’d be better off spending time on your tune up and using less booster. Or none at all unless it’s a fuel conditioner.
 
Rat Bastid said:
Ok, I doubt that Lucas is actually raising the octane two FULL POINTS. It may raise it .2 points but not 2 points. Very few octane boosters will raise octane 2 points.

There is far more to fuel than octane rating. I think you should reduce the Lucas octane booster by half (half of how many ounces per gallon you are now using) and work on your tune up.

Adding all that booster is IMO a waste of money. I’d have to see the rest of what your build is, but I think you’d be better off spending time on your tune up and using less booster. Or none at all unless it’s a fuel conditioner.
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Thanks
 
in my experience with plugs i could never get a proper reading using a fuel additive , it near always turns your plug ornge or tanish color .
 
R68DartGT said:
This came out of an indy cylinder head engine and they recommended 93 octane. Problem is in my neck of the woods we only sell 91 octane. It'll spark knock with out it.
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Really? So two research octane points less make it spark knock? That's pretty incredible.
 
I've seen a few tests were additives didn't really do much...My small cam 340 will detonate on 91 and always feels like it's being held back even when you can't hear it. On 93 octane it runs perfect and pulls hard.We're lucky, it's available here at a few stations.
I have ridden in friends' cars that really roar and just sound a bit "off" and don't pull like they should. I tell them it's detonating but they don't believe me because they can't hear it. It's a few bucks more per tank that i gladly pay.
 
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