E-85
Senior User
Joined: Dec 2003
Posts: 337
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Originally Posted by rusty70f100
I see one myth here that needs to be addressed. That is:
"Ethanol makes less power than gasoline because it contains less energy."
If both fuels were run at the same air-fuel ratio, then yes, the ethanol would make less power. But this is never the case in a well-tuned FFV.
Stoichiometric ratios:
Gasoline (100% iso-octane): 15.2:1
Ethyl alcohol: 9:1
E85: 9.93:1
Energy content, in BTU/LB:
Gasoline (100% iso-octane): 20,750
Ethyl alcohol: 13,160
E85: 14298.5
So it would look like E85 makes less power, right? Wrong. Take a look at what happens when we figure in the air/fuel ratio, to figure energy released at stoichiometric mixtures:
Gasoline: 20,750 / 15.2 = 1365.13
Ethyl alcohol: 13160 / 9 = 1462.22
E85: 14298.5 / 9.93 = 1439.93
So we can see that running at stoichiometric ratios, ethanol and E85 do release more power.
Now lets look at the ratios at which each fuel makes maximum power:
Gasoline: 12.5:1
Ethyl alcohol: 6.5:1
E85: 7.4:1
Now lets figure up how much energy is released for each fuel:
Gasoline: 20,750 / 12.5 = 1660
Ethyl alcohol: 13,160 / 6.5 = 2024.62
E85: 14298.5 / 7.4 = 1932.23
So at the ratio at which they make maximum power, ethyl alcohol and ethanol blended fuels come out on top. I hope this puts and end to the debate as to what makes more power in an FFV.
Throw the high octane into the mix, and you could run a high compression engine on these ethanol fuels and make even more power, and raise the efficiency. Of course, then you lose the ability to run gasoline. But you would get your mileage back, plus you'd be making a whole lot more power!
To me, ethanol and ethanol blended fuels are clearly superior to gasoline.
"Ethanol makes less power than gasoline because it contains less energy."
If both fuels were run at the same air-fuel ratio, then yes, the ethanol would make less power. But this is never the case in a well-tuned FFV.
Stoichiometric ratios:
Gasoline (100% iso-octane): 15.2:1
Ethyl alcohol: 9:1
E85: 9.93:1
Energy content, in BTU/LB:
Gasoline (100% iso-octane): 20,750
Ethyl alcohol: 13,160
E85: 14298.5
So it would look like E85 makes less power, right? Wrong. Take a look at what happens when we figure in the air/fuel ratio, to figure energy released at stoichiometric mixtures:
Gasoline: 20,750 / 15.2 = 1365.13
Ethyl alcohol: 13160 / 9 = 1462.22
E85: 14298.5 / 9.93 = 1439.93
So we can see that running at stoichiometric ratios, ethanol and E85 do release more power.
Now lets look at the ratios at which each fuel makes maximum power:
Gasoline: 12.5:1
Ethyl alcohol: 6.5:1
E85: 7.4:1
Now lets figure up how much energy is released for each fuel:
Gasoline: 20,750 / 12.5 = 1660
Ethyl alcohol: 13,160 / 6.5 = 2024.62
E85: 14298.5 / 7.4 = 1932.23
So at the ratio at which they make maximum power, ethyl alcohol and ethanol blended fuels come out on top. I hope this puts and end to the debate as to what makes more power in an FFV.
Throw the high octane into the mix, and you could run a high compression engine on these ethanol fuels and make even more power, and raise the efficiency. Of course, then you lose the ability to run gasoline. But you would get your mileage back, plus you'd be making a whole lot more power!
To me, ethanol and ethanol blended fuels are clearly superior to gasoline.
In our real world purchase of gasoline (by volume), it contains about 35 megajoules per liter while E85 is about 24.5 MJ/L. (sorry, too lazy to convert the units right now, but it's the ratio that is important) Basically, gallon for gallon - the way we buy it, ethanol has about 70% the energy content of gasoline. It does burn a little more efficiently (I have seen numbers quoted around 12%) you can also run higher compression and there is no need to bend timing curves around 'detonation zones' due to poor fuel as with gasoline.
Sick 'n Tired
Joined: May 2006
Posts: 2,969
Likes: 47
From: League City, TX
Originally Posted by rusty70f100
Stoichiometric ratios:
Gasoline (100% iso-octane): 15.2:1
Ethyl alcohol: 9:1
E85: 9.93:1
Energy content, in BTU/LB:
Gasoline (100% iso-octane): 20,750
Ethyl alcohol: 13,160
E85: 14298.5
Gasoline (100% iso-octane): 15.2:1
Ethyl alcohol: 9:1
E85: 9.93:1
Energy content, in BTU/LB:
Gasoline (100% iso-octane): 20,750
Ethyl alcohol: 13,160
E85: 14298.5
We can do the paperwork all night long (god knows I could use the O-chem and P-chem refresher), but eventually we have to move out of the lab and test for results. My results and and wallet show a 30% decrement.
Post Fiend
Joined: Jan 2003
Posts: 8,600
Likes: 4
From: Iowa
I got some numbers from here:
http://www.ext.colostate.edu/Pubs/farmmgt/05010.html
And some numbers from here:
http://www.drivingethanol.org/motors...teristics.aspx
I'll leave it to the readers to determine what came from where. For the E85, I used ethanol numbers and gasoline numbers in appropriate percentages (15% gas 85% ethyl alcohol). In the real world that varies between 70% ethanol and 85% ethanol depending on the season, so the results will vary a little there.
You'll also note I used the numbers most favorable for gasoline. The second link I supplied only lists pump gasoline as having 18,700-19,100 BTU. I thought someone would probably squawk, as most people do every time the dreaded word "ethanol" is mentioned, so I used the higher number.
Basically, there is no theorizing this other than for power. Every flex-fuel vehicle is different. Every driver is different. Most every fueling location will have it priced differently. The best advice I can give at this point in time is to go try about 10 consecutive tanks full of it, to allow the computer time to adjust, and see where you're at.
You have my results on the first page. We're coming out way ahead with the E85. As always, your mileage may vary.
I'm for options. Having an option is better than not having one and being stuck paying whatever the oil companies want for gasoline, as far as I see it. Maybe I'm wrong. But it's working for me...
http://www.ext.colostate.edu/Pubs/farmmgt/05010.html
And some numbers from here:
http://www.drivingethanol.org/motors...teristics.aspx
I'll leave it to the readers to determine what came from where. For the E85, I used ethanol numbers and gasoline numbers in appropriate percentages (15% gas 85% ethyl alcohol). In the real world that varies between 70% ethanol and 85% ethanol depending on the season, so the results will vary a little there.
You'll also note I used the numbers most favorable for gasoline. The second link I supplied only lists pump gasoline as having 18,700-19,100 BTU. I thought someone would probably squawk, as most people do every time the dreaded word "ethanol" is mentioned, so I used the higher number.
Basically, there is no theorizing this other than for power. Every flex-fuel vehicle is different. Every driver is different. Most every fueling location will have it priced differently. The best advice I can give at this point in time is to go try about 10 consecutive tanks full of it, to allow the computer time to adjust, and see where you're at.
You have my results on the first page. We're coming out way ahead with the E85. As always, your mileage may vary.
I'm for options. Having an option is better than not having one and being stuck paying whatever the oil companies want for gasoline, as far as I see it. Maybe I'm wrong. But it's working for me...
Senior User
Joined: Aug 2005
Posts: 225
Likes: 0
From: Copperas Cove, Tx
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Post Fiend
Joined: Jan 2003
Posts: 8,600
Likes: 4
From: Iowa
Originally Posted by bridge
Thanks Kurt, looks like I've got some homework. BTW, I see you're from Iowa. Aren't there lots of corn fields up there? Hmmm, you're not a corn farmer are you?
And yes, there are a lot of corn fields. But why all the hate towards farmers? They're good honest people trying to make a living. And what do farmers do when they actually make money? They reinvest it into the US economy! Being in Iowa, I have a unique perspective on this. I see farmers all the time driving around in new Ford (and other make) trucks. Farm equipment doesn't come cheap either. Honestly, I'd rather support these guys than Sheik Abdul (or whatever his name is) or the price gouging oil companies.
Now you have my opinion on the issue.
Sick 'n Tired
Joined: May 2006
Posts: 2,969
Likes: 47
From: League City, TX
Originally Posted by rusty70f100
Actually, no! I work on computers. I wish I was a corn farmer though...
And yes, there are a lot of corn fields. But why all the hate towards farmers? They're good honest people trying to make a living. And what do farmers do when they actually make money? They reinvest it into the US economy! Being in Iowa, I have a unique perspective on this. I see farmers all the time driving around in new Ford (and other make) trucks. Farm equipment doesn't come cheap either. Honestly, I'd rather support these guys than Sheik Abdul (or whatever his name is) or the price gouging oil companies.
Now you have my opinion on the issue.
And yes, there are a lot of corn fields. But why all the hate towards farmers? They're good honest people trying to make a living. And what do farmers do when they actually make money? They reinvest it into the US economy! Being in Iowa, I have a unique perspective on this. I see farmers all the time driving around in new Ford (and other make) trucks. Farm equipment doesn't come cheap either. Honestly, I'd rather support these guys than Sheik Abdul (or whatever his name is) or the price gouging oil companies.
Now you have my opinion on the issue.
Post Fiend
Joined: Jan 1997
Posts: 23,165
Likes: 18
From: Enjoying the real world.
Originally Posted by bridge
E85 is 85% Ethanol and 15% Unleaded Gas. Here in the south all of our "Regular Unleaded" now contains 10-15% Ethanol as well...hence the crappy gas mileage no matter which pump you pull up to.
Thanks for keeping the information "honest" for us Ken.
Sick 'n Tired
Joined: May 2006
Posts: 2,969
Likes: 47
From: League City, TX
Originally Posted by webmaster
You mean "here in Texas"? Regular unleaded isn't 15% ethanol in Georgia.
This is a good thing. It looks like more than 1.5 billion gallons of ethanol will come on line real soon. Once we reach 8 trillion/year then we can start giving the finger to Venezuela, Nigeria, Iran, Mexico, The Kingdom of Saud....
http://www.epa.gov/mtbe/contacts.htm
http://www.bizjournals.com/atlanta/stories/2006/01/09/story1.html?t=printable
Last edited by bridge; May 20, 2007 at 12:14 PM.
Senior User
Joined: Dec 2003
Posts: 337
Likes: 0
Originally Posted by screwy
I wonder what’d happen if you supercharged a 5.4 then ran E85.