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Old 09-21-2012, 08:30 AM
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Default Ethanol mileage

I've read a lot of the ethanol threads but have never seen mileage/gph mentioned. In vehicles it is considerably lower. I wonder if the increase in mileage doesn't offset the higher cost of non-ethanol fuel. Does anybody know for sure?
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Old 09-21-2012, 08:38 AM
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I don't comprehend your comment.

Ethanol laced gasoline has less energy content. Thus, it takes more fuel to go X distance. In other words, it provides less mileage per gallon.

You mention "the increase in mileage". That is contrary to all that I read about ethanol. We take a double hit. The fuel costs more per gallon and we get less miles per gallon. A lose lose proposition.

Don't get me started about the taxes we lose subsidizing the manufacturer of ethanol in the first place. Or, the adverse effects that it has on corn prices. And all things related to the use of corn.
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Old 09-21-2012, 08:52 AM
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jethro1, when he refers to the "increase in mileage", he's referring to non-ethanol fuel.

BAITBUDDY, depends on the price delta, and the car/boat you're talking about.

I know for my car, I lose about 10% in mileage (33/34 mpg to 30/31 mpg) going from straight gas to 10% ethanol gas. So if the straight gas (if you can find it!) is 10% or less more money, then that's your break-even point. Where I live, there's a nearby gas station that sells (just recently started) non-E gas, but it's about 15% more than 10%-e gas... still, I use it on the boat and lawn equipment -- definitely worth the price difference to me.

Corn-based ethanol is stupid for many reasons. Main one being it's the govt's idea...
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Old 09-21-2012, 08:54 AM
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Sorry i wasn't clear. My question is: Does non ethanol fuel in my boat really cost me anymore per mile traveled than fuel with ethanol. (Without consideration to costly mechanical problems)
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Old 09-21-2012, 08:56 AM
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Thanks Ed P that 10% number was what I was looking for.
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Old 09-21-2012, 08:57 AM
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I understood what you meant, is the higher cost of non-E fuel made up by the increase in economy over E-fuel. Wish I could find/buy non-E to test your theory. I don't mind E-gas for things that run regularly (car). The boat/mower/etc are driving me nutz trying to keep them running long term.
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Old 09-21-2012, 08:59 AM
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If you are comparing E10 it has about 3% less energy per volume and that is about inline with what I see in my car.

E85 is about 30% less energy content and since cars that can run E85 are tuned and optimized for it they seem to get 30% less MPGs on it in my experience.
Based on testing I've seen posted on other forums (all car engines) Newer engines seem to get close to 3% worse MPGs, I assume manufacturers consider E10 in their tunes. Older engine can get up to 5% worse.

So paying 3-5% more for non-ethenol should be made up for with fuel economy versus buying E10. Most of the extra cost at Marinas are government fees and taxes related...and I'm sure there is a bigger mark up at the marina.
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Old 09-21-2012, 09:04 AM
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Gasoline has 114,000 BTUs of energy per gallon
Ethenol (E100) has 76,100
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Old 09-21-2012, 09:55 AM
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I loose .20 to .25 mpg. When we are talking 2.7 mpg it is a big loss.
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Old 09-21-2012, 10:02 AM
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Quote:
Originally Posted by VTXrider View Post
Gasoline has 114,000 BTUs of energy per gallon
Ethenol (E100) has 76,100
E10 would be a loss of ~3.3% of the BTUs, all else being equal
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Old 09-21-2012, 12:37 PM
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Default E10 MPG reduced further, due to higher oxygen content of fuel

An average boat motor (above 75 hp) should expect to see a 10 to 15% reduction in MPG.
20% reduction not unusual for an older, larger 250hp+ boat engine.


While a newer small, 4 cyl. auto might only see a 3% reduction, several other variables adversely effect greater reduction in boats and other specialty engines...
Example: Boat motors lack advanced computerized fuel system that can/will adapt to higher oxygen content of fuel, like autos do...

Plus, when comparing E0 to E10 for boat engines, there's nothing more important to consider than "alcohol attracts and absorbs water".
Since boats at highest risk for water absorption into tank due to environment and vented fuel system, fuel dilution due to water absorption drops MPG even further.

So many other reasons to choose E0 over E10, if you're lucky enough to still have a choice, but when just considering fuel-efficiency/MPG,
unless station over-pricing E0 (many in Southeast do), E0 will always cost less to run, than E10 in a boat motor.

E0, ethanol-free price to station/fuel distributor usually only about about 20 cents/gallon more.
My customers in FL have reported ethanol-free gas over-pricing as much as 75 cents/gallon more!

Regardless I would still always choose E0 for boat, when all other factors considered such as: deterioration of engine parts, decrease life of engine, higher risk for phase-separation of fuel, shorter shelf life for E10,etc.
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Old 09-21-2012, 01:30 PM
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It is a loss, but it's not 10%. If straight gas puts out 115 kbtu, and 100% ethanol puts out 76k btu, then a 50/50 mix would put the average of the two, or 95.5kbtu. Since e10 is 90% gas and 10% ethanol, you take 90% of gasoline btu (103.5) plus 10% of ethanol (7.6) and add them together, a gallon of e10 would put out 111 kbtu.

So when you compare 115 to 111, you see it's still putting out 96.6% of the same btu output, and winter gas has even a smaller margin.

In short, even if ethanol didn't contribute any energy at all, the 9/10ths of a gallon of gas would still put out 90% of what you had. So for e10 to drop your mileage by 10%, ethanol would have to have zero energy output. I know ethanol sucks, but overstating the problem doesn't fix it.

That said, I would be perfectly content getting rid of ethanol completely and going back to straight gas.
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Old 09-21-2012, 01:37 PM
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Straight gas and leaded fuel for my classic mustang damn it!!
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Old 09-21-2012, 01:48 PM
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The major difference is the increased cost of repairs caused directly by ethanol laced fuel.
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Old 09-21-2012, 01:50 PM
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Quote:
Originally Posted by billinstuart View Post
The major difference is the increased cost of repairs caused directly by ethanol laced fuel.
Don't forget increased maintenance costs. I don't know about you, but I'm assuming you replace fuel filters a lot more frequently now.
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Old 09-21-2012, 02:48 PM
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I've seen a reduction of about 12.5%, but hard to say that it is totally e10's fault as I am pushing 420K miles on my Honda Accord. Love those Hondas, at least in a car.

I just wish we had a choice, we don't. Not cool.
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Old 09-21-2012, 08:55 PM
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Quote:
Originally Posted by jobowker View Post
It is a loss, but it's not 10%. If straight gas puts out 115 kbtu, and 100% ethanol puts out 76k btu, then a 50/50 mix would put the average of the two, or 95.5kbtu. Since e10 is 90% gas and 10% ethanol, you take 90% of gasoline btu (103.5) plus 10% of ethanol (7.6) and add them together, a gallon of e10 would put out 111 kbtu.

So when you compare 115 to 111, you see it's still putting out 96.6% of the same btu output, and winter gas has even a smaller margin.

In short, even if ethanol didn't contribute any energy at all, the 9/10ths of a gallon of gas would still put out 90% of what you had. So for e10 to drop your mileage by 10%, ethanol would have to have zero energy output. I know ethanol sucks, but overstating the problem doesn't fix it.

That said, I would be perfectly content getting rid of ethanol completely and going back to straight gas.
Don't know what to tell ya. I've thought of the math too, and it doesn't work out.

With non-E gas, I get 33/34 mpg in my Mazda MX-5. With e10, I get 30/31 (sometimes 31.5) mpg. That's about 10% loss. I agree it shouldn't be that much of a loss mathematically, but thems the facts.

Less energy, same price, bad for your boat/lawn gear, bad for many other reasons. Incredibly stupid idea.

Ethanol sucks. There's nothing good about it. Nothing.
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Old 09-21-2012, 09:03 PM
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There will be less fuel economy on a car since it has an O2 sensor and the ECU will close loop on the exhaust gas to keep the burn at a lambda of 1. On an boat with an open loop system, there won't be as much impact since the engine will just run a bit leaner depending on the system (inboard, outboard, carb, fuel injection).
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Old 09-21-2012, 09:12 PM
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I can tell a difference in my car and truck with a 3-4 MPG difference in my 07 Corolla and a 3 MPG difference in my RAM 1500 Hemi. I try to only run 100% gas in my boat but some times you have to bite the bullet and run the E10. I can tell a difference in Power and MPG in the boat but it is not near as bad as my Corolla. I average 4.3 in the boat with 100% gas and 3.8-4.0 with E10. That could also be due to load differences and trolling speed/conditions. I hate the Ethanol crap mainly because it is a pure $$$$ grab by the GOV and Special Interest Groups. If we are trying to get off foreign oil why put out a product that causes us to buy more foreign oil by lowering our MPG????? Big Gov makes a ton of money off of Gas Taxes and they also make big $$ off of Food Taxes .... Both have gone up with the addition of Ethanol Fuels based off of CORN!!

CORN = The latest 4 letter word
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