Help me understand E85

[Cory S]

Yes that's correct, for fuel sold as "e85" but they were asking about regular e10 fuel. Which is always 10% (or sometimes 9%).

Haha! Another one to ponder. I’ve tested a 50 mile radius of gas pumps up here and I’ve never got more than 6% Ethanol, with most being 3-5%. The 10% statement still states “up to 10%”.

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[GilmourD]

Summer blend vs. winter blend doesn't have anything to do with e content, It has to do with the volatility of the fuel.

In cold months a more volatile fuel will have the same effective octane as a less volatile fuel in warm months.

Imagine how fast acetone evaporates vs water. Acetone is more volatile, in the cold more volatile compounds will evaporate slowly, in the summer they evaporate more quickly. The compound they use is butane, there is more butane in winter blend fuel.

In high performance applications we find that this isn't the case, and winter blend does not behave the same even in the cold. However they use the same amount of ethanol year round. At least near me. This was verified with an ethanol content sensor.

Well, I base that upon the fact that the "Contains 10% ethanol" sticker isn't on the pump all year.

 

[Cory S]

Well, I base that upon the fact that the "Contains 10% ethanol" sticker isn't on the pump all year.

“Up to 10%”

 

[junits15]

Well, I base that upon the fact that the "Contains 10% ethanol" sticker isn't on the pump all year.

You'd need to test the fuel to know for sure, but the point still stands, the primary difference between winter and summer fuel is not ethanol content, its butane content. So a flex tune wont fix the issue as it does not detect butane content. I don't know if the coyote motors have octane learning but I'd bet they do, because ford puts it in everything lol. That would be a far better method of adjusting for winter/summer fuel.


Plus we're only talking 10% here, that's not enough to make an appreciable difference, the stoichiometric value for e10 is 14.1 compared to 14.7 for e0. Most cars run at 14.7 regardless of e content anyway

 

[Cordero1]

https://www.ebay.com/itm/125423158697

 

[GilmourD]

You'd need to test the fuel to know for sure, but the point still stands, the primary difference between winter and summer fuel is not ethanol content, its butane content. So a flex tune wont fix the issue as it does not detect butane content. I don't know if the coyote motors have octane learning but I'd bet they do, because ford puts it in everything lol. That would be a far better method of adjusting for winter/summer fuel.


Plus we're only talking 10% here, that's not enough to make an appreciable difference, the stoichiometric value for e10 is 14.1 compared to 14.7 for e0. Most cars run at 14.7 regardless of e content anyway

Gotcha... So, why does that ethanol sticker not perpetually live on the pump and instead seems to be a seasonal thing?

 

[Mike Pfeifer]

The sticker is on our pumps year round in Chicagoland. I have not had to test a lot of fuel over the years, but every time I have, its been almost exactly 10%.

 

[LOL WUT]

I'm seriously thinking about getting the PBD Flex tune for my 21 Mach 1 and this thread has been very informative so thank you all for that! Another guy on FB says it is night and day difference on his Mach 1.
I only have one gas station near me with E85. It show a range of 55%-85%. I've tested 3 times this spring/summer and every time it was 70%.
This should be good right?

Do you have any Gas & Wash stations near you? I’m just south of the city and have several local Gas&Wash stations that clearly advertise on their pumps “minimum 70% ethanol content”. I fuel from these stations 100% of the time, test every fill, and can confirm the E content is consistently high.

 

[sk47]

Hello; I do not use other than 10% ethanol so have no direct experience with alcohol problems at higher concentrations. I was having problems with old lawn mower carbs for a while before I started using ethanol formula fuel stabilizer.

Back to the Engine Masters episode. I seem to recall them talking about the undesirable effects of alcohols in fuels. Pretty clear for older vehicles. In newer vehicles designed for 10% it seems logical they have components that tolerate alcohol.
A thing i recall is about the oil. When listing good and bad points there was some discussion of needing more regular oil changes. It was more so for methanol if memory serves. I will look at the episode again to see if any particular points come up.

 

[NFG19]

I thought e85 was supposed to be cheaper than gas? Saw that video today with Zander it was over $5 gallon, but he said it was below $2 a couple years ago. Is it supposed to be cheaper?

 

[junits15]

Gotcha... So, why does that ethanol sticker not perpetually live on the pump and instead seems to be a seasonal thing?

Honestly probably just cost, I couldn’t tell ya why different places change the concentration

 

[kz]

I thought e85 was supposed to be cheaper than gas? Saw that video today with Zander it was over $5 gallon, but he said it was below $2 a couple years ago. Is it supposed to be cheaper?

I've paid $2.95/gallon yesterday (87 is $3.90).

 

[NightmareMoon]

I thought e85 was supposed to be cheaper than gas? Saw that video today with Zander it was over $5 gallon, but he said it was below $2 a couple years ago. Is it supposed to be cheaper?

Generally yes, E85 should be ~30% cheaper, and probably gets 30% worse MPG. So your costs won't really go down per mile, but a gallon of it should be cheaper than 93.

Probably depends on where you live, how far you are from the refineries, etc.

 

[K4fxd]

Is it supposed to be cheaper?

It was subsidized. It may be again with the monstrosity that just passed.

 

[NFG19]

Gotcha ya! I thought about trying it on 19GT. Only had ONE station close to my house. So I never looked into it.

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