91 E10 vs 87 E0, BTU/energy differences

[volk06]

I usually run premium 91 E0 or 87 E0. The difference in price for 91 E0 from 87 E0 has jumped significantly. It's 0.65-.80/gal more than 87E10 depending on the station. However a few stations have 91 E10 for the same price as 87 E0.
For example right now here are my choices
87E10 2.23
87E0 2.63
91E10 2.63
91E0 2.88

Does anyone know the energy difference between 91 E10 and 87 E0? For the price I think 91E10 is better than 87E0? All politics and bias aside, I'm looking for some real data if it's available. The ecoboost runs much better on 91 than 87. I've been using 87 E0 in the focus but switched to 91E10 since it's the same price and it runs like [censored] on 87E10 in the winter. The Taurus, however, doesn't care and will drink anything.

 

[Vern_in_IL]

Notice the stickers on the pump says "Minimum Octane Rating". The actual octane could be higher, it just can't be lower. Pump gas also have a small mix from the previous customer. (say they bought 93, and you purchased 87, you will not get exactly 87, that is the minimal.

 

[Nate1979]

E10 does not mean 10% ethanol but up to 10%. It can vary station to station so you can't do a calculation
Also, BTU comparison is a waste of time, you need to know the mpg for each for your car. It can also vary.

 

[splinter]

Originally Posted By: volk06
...All politics and bias aside...

Follow the money.

Then run your own spreadsheets. ttyl

 

[shanneba]

A good overview-
https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

The only place I have seen any energy content specs for gasoline is on Sunoco race gas web site. Nothing for pump gas.



Sunoco 98 octane unleaded 0% ethanol
http://www.racegas.com/fuel/8
Stoichiometric Air/Fuel Ratio 14.6
Ethanol (volume%) 0
Lower Heating Value (Btu/Gallon) 115800
Lower Heating Value (Btu/Pound) 18240

Sunoco Green E15 98 octane
http://www.racegas.com/fuel/9
Stoichiometric Air/Fuel Ratio 14
Ethanol (volume%) 15
Lower Heating Value (Btu/Gallon) 108200
Lower Heating Value (Btu/Pound) 17500

Sunoco 100 octane unleaded, 9.8% ethanol -
http://www.racegas.com/fuel/17
Stoichiometric Air/Fuel Ratio 14.1
Ethanol (volume%) 9.8
Lower Heating Value (Btu/Gallon) 109200
Lower Heating Value (Btu/Pound) 17900

 

[TiredTrucker]

Yeah, just keep it simple. Run a few tanks of different grades/blends of fuel and see what the results are for different fuels. Then as the pump prices fluctuate seasonally, you can select the fuel that does what you want at the lowest cost. That is why I have been filling with E15 for most of this year. I get almost comparable mpg numbers from it as I do E10 and E0, yet E15 is 10 cents a gallon cheaper than E10, and E10 is 20-30 cents a gallon cheaper than E0. Run a few tanks of E10 and see what the average mpg is. Compare that to what you normally get using E0, and use those mpg numbers to divide into the price and see what you cost per mile is. Then go with whatever gives you the lowest cost per mile.