E0 91 octane versus E10 87 octane

[user removed]

For two months I have been trying some E0 91 octane fuel to see if there is a significant difference in mileage in my vehicles. The Vulcan 500 seems to like E10 regular better. Not sure about the Fiesta, it still has one tank of E0 left. With the price of gas dropping here the difference is price is getting to be larger and I want to try E10 for a while to see what the difference in mileage works out to be.

The bike reaches a point in the RPM range where it runs very smooth at about 50 MPH on E0. At lower speeds you can feel it acting like it is lugging, while on the E10 it will run smoothly down to 30 in 6th gear. It seems like the peak combustion pressure is later with the 91 E0 than it is with the 87 E10. Slightly faster initial combustion and higher pressure earlier seems to be what is happening.

It won't be that scientific with too many other variables, but I can tell you on the bike, I could ride it and tell you if it was one fuel or the other, it's that obvious. It even made a significant difference when I just put half a tank of E10 in it yesterday.

When regular was closing in on $3.90 a gallon the $4.09 for E0 was not that much difference in price but yesterday I bought regular for $3.59 a gallon. It will be interesting to see what the difference in mileage will be in the Fiesta.

regards
Mech

[BHarvey]

My car saw right at 8% better mpg on the 90-E0 than the 87-E10.

[D.O.G.]

We have E0 91 octane and E10 91 octane available in Australia.
Although my previous vehicles haven't seen much difference between the two fuels, the '98 Mazda I'm driving now sees up to 10% better mileage with E0, than the E10, for about 3.5% higher cost.

Maybe it's because we didn't have E10 when this car was produced? Those with newer model cars, that are tuned to run with E10, may get very different results.

[DOFZO]

Bumping an old thread.


I've got a 92 VX and started using E0 91 after finding a station that sells E0. I was just wondering if the E0 91 is worth paying $.60/gal more for it. I'm thinking not only in terms of cost and MPG, but whether or not E0 is better overall for an older engine.





ZO.

[Daox]

As Old Mechanic's original post shows, its highly dependent on the engine you're running the fuel in. Hopefully someone can give feedback on your VX engine. Otherwise you'll just have to test it out.

[user removed]

Not worth the miles and higher cost, $.60 gal. I might fill half a tank with mid range fuel (all E10 here) in the summer. Cuts down the spark knock on the bike and truck.

The Fiesta doesn't care, Wally World cheap stuff, $3.289 a gal last fill.

regards
Mech

[PaleMelanesian]

Back when both were available in this area, my Civic showed a 3% mpg drop when using E10. Now that's all we can find here, so I can't test with my Fit. I have tested 87 vs 93 and found no difference, so I expect any variance would come down to the ethanol again.

[roosterk0031]

Been playing with E blends in Cobalt, using indicated mpg instead of calculated cause I don't fill at the same station or top off the same. E10 tank a few weeks ago indicated 44.6 @ 47 mph average. (that was the highest E10 of recent so a little of an outlier).

E30/94 octane indicated 41.3 @ 47 mph. E45/98 octane 40.2 mpg @ 47 mph. Based on energy content E30 should give about 93% of E10 or 41.5 mpg, E45 87% or 38.8 mpg.

Disclaimer: I did replace a rear tire after the E10 tank and did a smaller front tire test in between. Smaller tires give a 2 mpg increases in indicated MPG, calculated as no change. The test was cut short due to tire failure.

E10 about 97% of E0 energy.

[redpoint5]

I observed about a 10% loss in MPG in the '96 Subaru Legacy when Oregon mandated E10. This doesn't make sense though since the ethanol content was only 10%. My observation of MPG decrease was as if 10% of the fuel was replaced by water.

I'm guessing my observation was skewed by other variables, and that the real loss was perhaps only 5%.

Ethanol for fuel in the States doesn't make sense. Perhaps it makes more sense in tropical climates, and for vehicles optimized to run that fuel.

[vrmouseyd15b]

From what I've driven, I seem to lose about 10% with the e-85. And I swear it killed my 99 kia sportage, but I didnt know anything about cars back then! To this day I won't run it unless it says "flex fuel" on the back of the car, and when I do, mileage still drops

Wazzzup rooster! You near the quad cities? I'd like to try and find some local ecomodders and have a meet or something!