E15 Fuel vs E10 Fuel

So some of our local gas stations have started to carry E15 octane 88 gasoline along with regular E10 87, 89, and 93. Is it ok to use E15 in place of E10? My manual for my 09 Focus SE specifically mentions maximum of 10% ethanol (wasn’t planning on running it in the Focus anyway, the price difference isn’t that significant for the size of the tank), but I don’t know if E15 was available at the time we purchased the vehicle.

Do not use gas with more than 10% ethanol.


That’s what I figured. I’ll happily pay a small amount more for the regular E10. It’s only a 5 cent difference anyway :slight_smile:

While E15 has now been approved by the D.O.T. for over-the-road use, not all vehicles are designed to operate on it. Flex fuel vehicles can operate on up to 85% ethanol, but since your owner’s manual says not to exceed 10%, stick with its recommendation.

By the way, I commend you for reading your manual. Far too many people don’t. Far too many would rather trust strangers on the internet than the written requirements of the manufacturer. I never did understand it. :relaxed:


The only way I’d use E15 in my car is if it was in a flex fuel vehicle what was capable of using E85, and even then, I’d have to do some calculations based on the price and the lower fuel economy to see if it’s worth it.


honestly, I’m probably one of the odder ones. I enjoyed reading the owners manuals when I was a kid, and I haven’t stopped reading them since. I know my grandfather has always appreciated it, because I’ve been able to quickly find the right pages to find parts numbers because I read them so often!

LOL, that’s not a bad thing. I too am odd. When I was a kid I loved to read. I used to sit for hours on end and read encyclopedias… never novels. Even now, I love to read… but never novels. I’m going back through a physics textbook right now just for something to read. I’ve also been plowing through an 826 page book entitled “The Constitution of the United States of America and Selected Writings of the Founding Fathers”. I got tired of hearing countless people screaming about what the Constitution says and decided to find out for myself. Please note that I will NOT get into any political debates with anyone on this forum, except where it involves automobiles. This is not the appropriate place to do so. :stuck_out_tongue_winking_eye:


In addition to your car not being designed for E15, it’ll hurt your mpgs. More ethanol = lower mpgs. E85 caused about a 30% drop, for example.

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Yep, I’ve done that too. I still love reading also, and I’m trying to get my kids bitten by the reading bug too (granted they’re 4 and 3 so they’re pretty much up for anything if you make it sound exciting enough). My paternal grandfather got me a copy of “The Way Things Work”, I’ve almost worn that book out from reading through it. It was so fascinating and a massive range of topics in it.

Good call avoiding political debates…I’ve tried to dodge those on here so far…this is way too nice of a forum to ruin with that :sunglasses:

I know, the article even took note of that near the bottom:

“One example shows a 2014 Ford Focus getting 32 mpg with regular gasoline, for an annual cost of $1,100. With E85, that same vehicle would get 22 mpg, with an annual cost of $1,300, according to the website.”

And yet people will still run out and keep using the E85 :sweat_smile:

We don’t even have E85 in Central Maryland. I think E85 is a Midwestern thing, and those that do buy it there do so to help corn farmers. That is a guess, of course, since I rarely get to the Midwest. Maybe Midwestern posters can tell me whether E85 sells much here.

if you bother to read the actual report, engine valves on cars not designed for E15 are getting pitted with ethanol

no wonder the idea of pushing ethanol content higher than 10% is floating around: it makes your car to die… slower than on the spot, but surely well before it should, effectively pushing you to buy a new car

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Amen to that comment! :relaxed:

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I have a 2017 Toyota 86 (formally the frs) not only does the book say no Higher than 10% E it also says it on my gas cap. But I’m sure most new cars also say on the gas cap as well. I live in Nevada more and more E15&E85 pumps are showing up. Instead of the E pumps I would much rather they put at least 93 octane regular gas in my state. As it is I have to mix 100 octane pump gas(approved for cars not avgas) and 91 to get 93 octane. This gets pricey as the 100 is 7.99/ gallon.
I wish they would stop making stupid blended gas as well summer and winter. If they would stop doing things like this gas would not only be better for the planet but cheaper as well. Plus it’s common knowledge that E gas hurts the cars if it didn’t all cars could run it no problem. Look how long it took us to realize what bad effect TEL gas(leaded gas had not only on us but the planet as well)

Why would the book need a dose of anything? :wink:

And, more to the point, exactly what is the dosage?
Exceeding the daily dosage could have dire consequences.

There are a few national chain gas stations where I live that are selling both E85 and ethanol free gasoline. Both are priced at a premium that makes them more expensive per mile than E10.

It’s has a do not use E15 or E85. If they want to push E products then it should have its own gas station that only carries E gas. All the rest of the gas stations should have non blended E free gas. Let people make there own choices what to use. If it is really better then they will sell more. But making all gas have a min of 10 is bs. If you are lucky to have a station that you can get E free do it. Save your car and trips to the repair shop or junk yard.


thats nice at least you have a choice if I could get E free 93 out here I would drive to get it even if it was a little more expensive.

The problem is that ethanol free fuel is it isn’t just a little more expensive. It is a lot more expensive, sometimes as much as a dollar more per gallon then E10. It is probably heavily taxed as well.