90 Octane with Ethanol or 88 without

[WinterMountaineer]

If you had a choice between 90 with Ethanol, or 88 without Ethanol:
a) which one would you use for reliability?
b) which for performance?

 

[caper11]

Anything below 91 octane is not worth using in a snowmobile regardless of the ethanol

 

[snow-doo]

If you like piston replacement,than the lower the better

 

[turboless terry]

If it was an na I would take the 88 without ethanol. I ride at 9000 feet. Over octane isn't gaining you anything

 

[christopher]

The HIGHER your altitude, the less Octane you will need to retard detonation (as a general rule) for a non-turbo.
So if you are up high enough you might get away with the 88....

 

[snowman67]

Would the detonation sensors catch it and retard timing even if you had to run 88 for some reason?

 

[StuckDownHill]

I would go 90 with ethanol if those were my only 2 choices.

For reliability, I would drain the gas any time the sled sat for more than a week and dump it in the wife’s SUV. Reason being is to get rid of any moisture that ethanol is know to readily absorb.

For performance, I want the higher octane rating to avoid detonation. I ride a Polaris and want to be able to set it to “premium/non-ethanol mode”. I know this contradicts what Polaris is recommending but I am under the assumption that ethanol mode will change my tuning and provide less power. If I start to see DET codes or break my plugs, I will change the mode.

This is what I am doing, as in Canada, Trudy mandated all our fuel to contain ethanol. Our 91 says “ may contain up to 10% ethanol” now.

 

[caper11]

I have been running ethanol fuels for years, haven’t had an issues. My brother had a snowbike that had to run ethanol to work with the tune in it because US fuel has more ethanol innit than Canadian fuel, most of the time Canadian fuel doesn’t have ethanol in it in the winter, so he mixed ethanol in the fuel, that bike ran extremely well.
Ethanol makes HP.

 

[800Gader]

I have been running ethanol fuels for years, haven’t had an issues. My brother had a snowbike that had to run ethanol to work with the tune in it because US fuel has more ethanol innit than Canadian fuel, most of the time Canadian fuel doesn’t have ethanol in it in the winter, so he mixed ethanol in the fuel, that bike ran extremely well.
Ethanol makes HP.

Volume of ethanol makes HP. Since ethanol has less BTUs, it takes more to get the same power and of course, drops mileage (I know, who cares about mpg).
Big thing is, can the fuel system flow enough to give designed power?.