Is Ethanol Robbing Me Of MPG?

[NoCO2]

It's funny you should mention this. I filled up last time at Costco fuel center. They say they use 10% Ethanol in their fuel (not up to 10%, just 10%) and so far, this tank has gone farther on X amount of gas (whatever X turns out to be) then any tank previously. I will know for sure what the millage exactly is when I fill up (probably today or tomorrow), but judging by the gauge, I just broke below the 3/4 line and I've already gotten about 180 miles (I have a picture of it at 100 miles with the needle still right at the top from this tank, but it's on my phone). So either I'm doing something very very right this time or ethanol is causing my car to run leaner, not spray more fuel.

[ttoyoda]

Higher octane than necessary reduces efficiency, as the burn is cooler. Increased octane is of no benefit if there is no pinging/detonation or the ignition can't be advanced to take advantage of it.

I agree with the second part, but do you have a source for the
"Higher octane than necessary reduces efficiency, as the burn is cooler. "
part. I would have thought the flame temperature would be controlled by only the heating value of the gasoline, and the amount of air in the mixture. Unless you meant that the heating value is reduced by WHAT they add to the gasoline nowdays to make the octane higher, since sadly that yummy tetra ethyl lead is no longer available.

[Frank Lee]

http://www.ethanol.org/pdf/contentmg...se_12507-1.pdf

[ttoyoda]

Frank Lee
That is a very interesting link. They don't seem to explain "why" this is going on, I wish they did. Perhaps the burn is faster, so more of the heating values is used for power rather than for heating up engine parts? Also I wish we made ethanol from something other than food, but that is a different rant..

[jesse.rizzo]

Originally Posted by SVOboy

While this is true, I think it's fair to say 87 octane e10 is 87 octane in the same was the 87 octane non-ethanol gas was 87 octane before the ethanol mandates.

Actually I read a few days ago that in areas that require e10, the regular gas may be the same octane as mid-grade or premium. I looked but couldn't find the article.

[LostCause]

Originally Posted by The Baron

Is it harder on an engine that isn't a "FlexFuel" vehicle? I'm pretty sure the German engineers who designed my car in the 1980's didn't do so with 10% ethanol in mind.

Flexfuel vehicles are a joke. They just have a few gaskets and rubber lines replaced with materials that won't corrode under high alcohol concentrations. E10 is too diluted to do anything.

I say look at the big picture. You are losing 3% in mileage to vastly increase the health of yourself and the environment. Not all things of value have $ signs preceding them.

Originally Posted by jesse.rizzo

Actually I read a few days ago that in areas that require e10, the regular gas may be the same octane as mid-grade or premium. I looked but couldn't find the article.

What's interesting is that ethanol, gallon to gallon, is generally cheaper than gasoline. Premium gasoline, which contains more ethanol by volume, is more expensive than regular.

- LostCause

[johnpr]

Originally Posted by LostCause

Flexfuel vehicles are a joke. They just have a few gaskets and rubber lines replaced with materials that won't corrode under high alcohol concentrations. - LostCause

flex fuel vehicles have more done than that, the computer can sense the difference in fuel and adjusts the amount of fuel used so that you get proper burn, this is not done in regular vehicles that is why regular vehicles cant run e85. now if you dont use e85 and your vehicle is flex fuel, that is where the joke comes in.

but from my experiences, e10 and e20 do not give every vehicle decreased mileage, in fact my highest mileage (in jeep2) prior to modifications was 19.91mpg and that was with e20, i increased tire pressures and have maintained an increase since then but have not used e20 since that tank. i am considering using e20 exclusively though.

[LostCause]

It is true the computer will change the A/F ratio to stoich, but it's a joke because the ethanol is essentially being wasted. It's the equivalent of buying premium gasoline for a grocery getter.

Ethanol belongs in an engine running an 11:1 or greater CR. Flexfuel vehicles only exist for governmental reasons. It's a way to meet environmental standards cheaply, without the requisite of actually doing anything.

Things may be different in the corn belt, but in California I doubt any flexfuel vehicle has seen a drop of E85.

- LostCause

[johnpr]

i agree with you, most flex fuel vehicles never see more then e15, i had a town and country which was flex fuel and i used e85 in there every time (with negligible mpg loss (1-2mpg)) but when i was in NC the closest place to get it was an hour and a half away so i never got it there

[Frank Lee]

I run E85 in non-flex fuel vehicles.