E15 vs E10 Gas Mileage (No More E15 for me)

And the higher the E the more oxygen it has in it.

 

I swear when i was in vermont and filling up with their non ethanol gas, i got better gas mileage with my tundra going back to connecticut.

 

I've tracked my mileage since I got the truck. Tanks with non-e gas get better mpg than those with etoh.

 

maybe so, but the ECU clearly retards timing with ethanol gas.

 

Above is my quote from another thread on here about running a tank of non-ethanol

 

I have only ran non-ethanol in my truck since new. (after the tank the dealer gave me) I average 24.X MPG, mostly highway miles on flat land. I’m sure the non ethanol has a lot to do with mileage, but I am 100% sure that it’s better for the engine, and I intend to have this truck for a long long time.

 

i get about 17 mpg, but that is about 1 hour of city driving and 1 hour idling for work. i can get 22-24 on the highway.

 

What? I've been tuning on e85 for near 20 years. The more e, the higher octane the less detonation and less retard. It's alcohol race fuel at the pump. It also creates a cooler intake charge which helps with retard and engine will run 10* or more cooler.

 

Yeah because e has about 30% less energy than gas. So the more e the worse the gas mileage.

 

You probably did.

E10 has less energy per gallon than 100% gasoline, about 3976 less btu.

For example, to propel the truck at a steady 60 mph requires X btu.

If there is less energy available (btu) per gallon of fuel more fuel must be consumed to do the same amount of work.

Gasoline: 116,090 btu 10% = 11,609
Ethanol: 76,330 btu 10% = 7,633
Reduced btu of E10 3976


Just to compare: Low Sulfur Diesel: 128,488 btu -- a comparable diesel powered vehicle would get better mileage.

Published energy values vary, these are the ones I used:
https://nhcleancities.org/2017/04/can-compare-energy-content-alternative-fuels-gasoline-diesel/

 

And this is why I run premium fuel get better btu's

 

Premium is e10 in many locations.

 

Yeah your right. If I run e10 regular I get horrible mpgs . I'm at sea level so it works great for me .

 

there's still 10% ethanol in premium in most places

 

If we had non ethanol premium I would run that.

 

If you are referring to "premium fuel" as in higher octane (89,90,91, etc) it doesn't have any more btu than regular 87 octane fuel. Octane is only a measure of a fuels resistance to unplanned ignition. As a general rule higher performance engines have higher compression and the manufacturer will suggest or require higher octane fuels.

The only btu difference is between ethanol and non ethanol fuels with the non ethanol having more btu per gallon.

Depending on your age you may be familiar with older vehicles equipped with carburetors that would exhibit pre-ignition when climbing hills or accelerating with a heavy load. This was commonly called: spark knock, octane knock, compression knock, pinging or pinking. This occurs when the fuel/air mixture ignites in the cylinder before the spark plug fires. Higher octane fuels help minimize this.

Modern vehicles are much less prone to pre-ignition as the computer can detect the pre-ignition and control the timing accordingly.

 

Is the varying ethanol content available in E85(51-83%) a consideration when tuning?

 

Yet less energy

 

If I go to Wawa, I usually give my truck a "treat" with ethanol free or premium. I get better MPG's, but the cost is negligible. I just stick with 87 now

 

Is that a recent picture? Because I am paying double that in CA…

But to point out, this debate about negligible differences in fuel economy is stupid. No two tanks are equivalent. Maybe if OP gets a 5mpg difference doing the same commute, but really this is not a fair experiment. Only way to truly measure these differences would be in a much more controlled environment.