Clones type of fuel

JD17

New member
Stock clones seem to run good on Regular 87 octaine pump GAS, that is the only legal fuel for Stock clone.
 

RadialFin

New member
Lowest octane of the purest gas you can get.

Take from it what you will but I tested non ethanol 91 and regular 87 back to back on a sprint track last weekend. The 87 was .7/lap faster over a 59 second lap. I can drive laps within .1 of each other so that part is consistent. Stock timing, no jetting change. Ran the 91 to the bottom of the tank, filled with 87 and went straight back out. First lap out of the gate was faster than anything on 91. I expected the 87 to maybe be a little quicker, but wasn't expecting a butt dyno difference.

Check with your track regarding fuel.. they may have a specified gas station and take a digtron reading from that for reference...
 
I’ve been preaching this for 20 years. High compression engines need high octane fuel, in most cases, stock kart engines are not high compression.
Octane is not a measure of power, it’s a measure of how good it can resist detonation. The higher the compression, the more likely high octane is going to be better. It’s the compression that gives you the power, not the octane.
 

RadialFin

New member
I’ve been preaching this for 20 years. High compression engines need high octane fuel, in most cases, stock kart engines are not high compression.
Octane is not a measure of power, it’s a measure of how good it can resist detonation. The higher the compression, the more likely high octane is going to be better. It’s the compression that gives you the power, not the octane.
Al you're preaching to the choir here haha. You say this a lot and I say this back, you're taking octane rating in isolation of other factors such as the composition of the fuels in question. In this case the 87 contains 10% ethanol (YUK!) and the 91 is a "pure" gas. Octane numbers here are the pump numbers of course R+M/2.
I expected the 87 might perform better due to lower octane, just not to the degree that it did considering it also had ethanol in it's composition. I think to assume one would be quicker than the other off the bat, just because of the octane number would be a mistake.
 
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