54 replies to this topic

[rbodor3]

who's done it, and results. begin: discussion.

e85 is typically cheaper (if you can find it) than premium gas, you can run higher octane safely, although you get worse gas mileage (haven't looked at any numbers on this so don't know if this evens out on the cost), and you have to get significantly larger injectors. I've also heard issues with spark plugs, and that it eats fuel pumps for breakfrast. And, of course, you'l need a retune if you want more ponies from it.

[Keaton85]

Sorry but VS is anti-E85.... like most vehicle forums.

It would be great if we could get some tuning for our vehicles and really work with E85 correctly. BUT no one on here would bother.

1: It doesn't eat fuel pumps
2: The fuel system is 100% compatible
3: A tune should be able to flow enough fuel for E85 (about 30%)

I run E85 without a tune or any modifications. I would benefit greatly from proper supporting mods but I don't run E85 enough to make it worth it. If I have an E85 station close then I would try and get a tune.

If I had an E85 station close*

[Che'_Moderator]

[Keaton85]

haha, gameover

[Tightmopedman9]

E-85 is not cheaper. Yes it is cheaper by the gallon, but it is 30% less effcient; as cost per mile goes, it is more expensive.

The real problem with E-85 though is that you need higher tolerance piston rings to make sure it doesn't leak past the pistons and destroy the lubricating ability of your oil. Maybe with our cars new it wouldn't be much of a problem, but with 100k+ miles your looking at very frequent oil changes to make sure you don't run into problems.

Problems aside, it would be a nice alternative. Much higher octane rating, and a high specific heat density (not that it would make that much of a difference). Also, the benefit to the environement (if you could get a non corn based E-85) would be a nice plus.

[Keaton85]

Tuned correctly you can get that number down by a lot. I get about a 25% decrease in fuel economy without a proper tune on E85 highway.

All the "myths" aside, if we actually at least TRIED to get it tuned correctly for our vehicles then we could do some really topics on it. We have no really info on how it would handle with our vehicles tuned correctly, period.

no real*

[Jardim]

E85 or E100 would be nice if it was widely available like it is back at home. If the demand (or use) was higher then we'd see some E85 tunes by now.

[ozzimark]

Tightmopedman9, on 12 December 2011 - 06:48 AM, said:

Yes it is cheaper by the gallon, but it is 30% less effcient; as cost per mile goes, it is more expensive.

The real problem with E-85 though is that you need higher tolerance piston rings to make sure it doesn't leak past the pistons and destroy the lubricating ability of your oil.

E85 is actually more efficient than gasoline when tuned for, the issue is the lower energy density in the fuel: http://delphi.com/pd...010-01-0619.pdf

I haven't heard that problem related to the rings. I do know that ethanol is hygroscopic, and when that water burns, it creates a lot of acid that destroys the oil pretty quick. That can be worked around by using an oil with a really high TBN, or a diesel oriented oil.

[Gideon35T]

There's several VS members who use it as an additive to premium for the octane boost. I've yet to try it in any of my vehicles but a friend has been experimenting with mixing here locally. He started light but eventually saw reasonable gains at/above 15% E85 added to the 91 premium we have down here. Now he regularly runs ~20% E85. However, he's not tuned for it and the fuel system in his scoobie is already upgraded for feeding higher boost levels. Once its back to the blistering summer heat here in AZ I'm going to try a mixture and see how the S60 responds.

[550]

Something I always wondered when using E85 as an additive is the stoichiometric value of E85 Vs regular gas

http://www.e85perfor...read.php?p=5048

Quote

Lambda|E85 AFR|Gas AFR
0.700 6.832 10.290
0.710 6.930 10.437
0.720 7.027 10.584
0.730 7.125 10.731 @ Max Power Multi Turbo
0.740 7.222 10.878
0.750 7.320 11.025 @ Supercharged/Turbo
0.760 7.418 11.172
0.770 7.515 11.319 @ Max Power NA
0.780 7.613 11.466
0.790 7.710 11.613
0.800 7.808 11.760 @ Consistant Race
0.810 7.906 11.907
0.820 8.003 12.054
0.830 8.101 12.201
0.840 8.198 12.348 @ Part throttle RACE
0.850 8.296 12.495
0.860 8.394 12.642
0.870 8.491 12.789 @ Idle
0.880 8.589 12.936
0.890 8.686 13.083
0.900 8.784 13.230
0.910 8.882 13.377 @ Part throttle STREET (economy)
0.920 8.979 13.524
0.930 9.077 13.671

Wonder how the partial mixing effects things.

[Gideon35T]

Finding an average (taking into account the % difference) would be easy assuming that mixing the two doesn't impart an unknown variable. Great info though, I'll bookmark this page simply for that chart.
Assuming a 20% E85 and 80% regular gas ratio then (according to the above chart) ...

Max Power Multi Turbo = 10.009

However, we already know that those numbers can never be perfect as there are other factors which determine optimum power besides stoichiometric burn.
My biggest question is if the O2 sensor will rear accurately when E85 is introduced ...

[Gideon35T]

For the partial mix I come up with the following numbers. I rounded a little and only used the key values but assuming no odd variable when the two are mixed these appear to be the stoichiometric for 20%, 25%, and 33% E85. I chose those because they are probably the most likely mixtures to be tried and the numbers are easier to work (lol).

[Gideon35T]

Hmmmm ...

The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual-octane engine tests."

Opinions?

[Che'_Moderator]

Gideon35T, on 13 December 2011 - 03:16 PM, said:

Hmmmm ...

The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual-octane engine tests."

Opinions?

Its why I -1ed your previous post. It does not work that way. Octane on most E85 is ~93-94. IE the exact same as premium fuel.

[Gideon35T]

Ahhh, so it the chart that 550 posted incorrect? It's what I based mine off of.

Here in AZ 91 is premium. So there'd still be a gain ... however if E85 = 94 then it would take 33% E85 just to raise ONE full octane point. That's fairly disappointing then. Even a full E85 conversion hardly seems worth it compared to adding some race gas to premium. And with the greater quantities of E85 needed vs Gas I can't see the value in swapping.

[Che'_Moderator]

Gideon35T, on 13 December 2011 - 04:45 PM, said:

Ahhh, so it the chart that 550 posted incorrect? It's what I based mine off of.

Here in AZ 91 is premium. So there'd still be a gain ... however if E85 = 94 then it would take 33% E85 just to raise ONE full octane point. That's fairly disappointing then. Even a full E85 conversion hardly seems worth it compared to adding some race gas to premium. And with the greater quantities of E85 needed vs Gas I can't see the value in swapping.

Thats wrong also. Another thing to remember this is all based on 55 gallon drums. Crap in the inground tanks is garbage compare to race grade E85. Just use MTBE like a normal person. Or low terta lead.

[550]

Gideon35T, on 13 December 2011 - 04:45 PM, said:

Ahhh, so it the chart that 550 posted incorrect? It's what I based mine off of.

Here in AZ 91 is premium. So there'd still be a gain ... however if E85 = 94 then it would take 33% E85 just to raise ONE full octane point. That's fairly disappointing then. Even a full E85 conversion hardly seems worth it compared to adding some race gas to premium. And with the greater quantities of E85 needed vs Gas I can't see the value in swapping.

I wouldn't say it's wrong, I think you are misinterpreting the octane with the stoichiometric properties. Just because the octane rating of E85 isn't necessarily 105 doesn't change where E85 is stoichiometric.

[Che'_Moderator]

550, on 13 December 2011 - 04:56 PM, said:

I wouldn't say it's wrong, I think you are misinterpreting the octane with the stoichiometric properties. Just because the octane rating of E85 isn't necessarily 105 doesn't change where E85 is stoichiometric.

Not its craptastic octane rating its craptastic hydrophilic properties.

[Gideon35T]

Ahhh, making more sense to me now. Is the additive to premium gains just a butt dyno feeling then? assuming both are simply gas station sludge that is.
I could see it being a more feasible setup if one were to buy the drums directly (I know sunoco lets you). Then create whatever mixture you want.
Still, seems hardly worth it compared to some race gas or other additives available as Chuck suggests. At least for a street car anyways.

[Che'_Moderator]

http://volvospeed.co...rs_general.html <-- good read.