I stopped for fuel and the station had 87 without ethanol
and 91 with 10% ethanol, I wasn't sure which one to use.
I went with the 91. Is it okay to use the lower octane without ethanol?
I figured I better stick with the higher octane rating

Thank's, I am new at this
2012 Triglide

 

Ethanol content and octane should be looked at separately. For the 91 octane source you are looking at, the blending of the fuel - to include the ethanol - has been done appropriately to produce the 91 octane rating.

Octane: "The measure of a fuel's ability to resist "knocking" or "pinging" during combustion, caused by the air/fuel mixture detonating prematurely in the engine." Higher octane allows for things like higher compression. You should use the octane rating that meets or exceeds the octane rating that your engine requires.

 

What does your owners manual say?

The manual for my 2006 Sportster says to use at least 91 Octane. Ethanol is safe to use in any modern vehicle, so you are better off running the higher octane with the ethanol than running the lower octane rated fuel without ethanol.

That comment applies to 10% ethanol gasoline mixture. Do not use E85, the 85% ethanol stuff in your bike unless your owners manual specifically says it is OK to use.

If you don' have your users manual you can download one online.

https://serviceinfo.harley-davidson....cle/lookupForm

 

Octane rating is the primary rating you need to be concerned with, and use what is recommended for your model. Modern engines are designed with Ethanol in mind, and it is simply not cost-effective to spend the extra money, even if you can find the correct rating for ethanol-free gas.

Older engines (I'd say prior to 2001 to be on the safe side) can have issues with fuel lines, etc. due to the ethanol content and can definitely benefit fro ethanol-free gas.

 

According to the EPA 10% Ethanol is safe to use in any year light vehicle. 15% should only be used in 2001 and newer vehicles.

I run 10% Ethanol in my 1997 and 2001 Sportsters with no worries of damage.

 

I've been running 87 ethanol free gas in my 07 Street Glide and 02 Softail for years with zero negative side effects.

 

For my bike, which calls for 91 octane, I'd go with the 91 octane E10. Bike is designed to run on up to E10. That said, I usually fill up with the 91 octane with no ethanol, but have used the E10 when it was all that I could get- usually when on a long trip.

I don't really see any difference in performance between the 10% and the 0% stuff. I don't track mpg.

 

I meant to say 2001 of course, I'll correct it. Problem I've heard with E10 is that it's not really consistent, and the actual mix can be as high as 15-16%, depending on location although I've never worried about it much, and never had a problem either.

 

If 91 octane is the spec, you must run 91 octane or better for best performance. Whether it has ethanol or not is of no consequence beyond leaving a little MPG on the table.

87 = NO
91 w/ethanol = better
91 pure = best

 

...one of the issues I've seen with ethanol is it's worse damage seems to be done in vehicles that are stored or used very little. Ethanol by nature absorbs moisture over time, so in rarely used vehicles it can bring water into the fuel. Stabil & SeaFoam seem to help and I always used it before storage. A few years ago a new gas station opened up by me that has "ethanol free" gas and it's now around $3.79gal. I fill up the vehicles I'm storing with it just prior to storing them. Ethanol too is a slight octane enhancer itself. Most modern vehicles have plastic, viton or stainless steel components that are compatible with ethanol. Older vehicles with rubber fuel lines, cork floats in carbs, steel fuel tanks can have issues over time if stored frequently.