What octane fuel and what ratio do you use in your saws

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chadihman

chadihman

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I can get 100 octane E free gas at a local gas station. I was going to mix it 40:1 for running in my ported MS460 and ported MS660. Is this ok? What are you pros. doing?
 
ELECT6845

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I can get 100 octane E free gas at a local gas station. I was going to mix it 40:1 for running in my ported MS460 and ported MS660. Is this ok? What are you pros. doing?

100 octane is no benefit unless your compression is well over 200. The ethanol free is awesome and that is a huge factor so you dont have to replace fuel lines and diaphrams. 40:1 is great also. I run VP SEF fuel mixed at 36:1 with Maxima formula K2.
 
chadihman

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Thanks for your thoughts guys! I was also wandering if it would be ok to lean my 460 to 14,500 rpms if I do a 40:1 rather than suggested 50:1? Would that cause it to overheat?
 
chadihman

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100 octane is no benefit unless your compression is well over 200. The ethanol free is awesome and that is a huge factor so you dont have to replace fuel lines and diaphrams. 40:1 is great also. I run VP SEF fuel mixed at 36:1 with Maxima formula K2.

Will 100 octane hurt the performance if my compression is under 200. I use the Stihl HP oil and the label states to allways use 89 octane.
 
BrocLuno

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The simpler the fuel formula the better - KISS.

Regular and 40:1 for run of the mill saws. Mid-grade and the same oil ratio for mildly ported saws with thin base gaskets. Radical ports and high comp need premium.

All the octane additives above regular cause the flame front to slow down and that may not be a good thing in a high winding 2 stroke. Complete fast combustion without any residual flame in the exhaust port (or minimized where possible) is the best for power and longevity. Delayed combustion can mess with transfer timing and create other issues. Run the lowest grade fuel your saw will tolerate for best performance and cleanest combustion.
 
blsnelling
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I can get 100 octane E free gas at a local gas station. I was going to mix it 40:1 for running in my ported MS460 and ported MS660. Is this ok? What are you pros. doing?

Thanks for your thoughts guys! I was also wandering if it would be ok to lean my 460 to 14,500 rpms if I do a 40:1 rather than suggested 50:1? Would that cause it to overheat?

What did your saw builder tell you?
 
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