Mileage with 10% ethanol blend?
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From: fl
1992 500E, 2006 E500, 2007 GL 450
Mileage with 10% ethanol blend?
Over the past 2 months all of my local gas stations switched to ethanol blend. It is supposed to be a max of 10% ethanol. But I have noticed a significant decrease in my mileage. I frequently make a 186 mile round trip drive in my GL 450. Virtually all highway at 70-85 mph. Over the course of dozens of trips, my usual fill after the trip had been 10 to 10.5 gallons. The last few trips with ethanol blend have consumed 11 to 12 gallons. It does not seem possible that 10% ethanol could have such an adverse effect on mileage.
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Possible. My friends with E85 cars don't use it as it burns or evaporates very quickly. It's cheaper, but they fill up a lot more. In Illinois, all we can get is 10%, so there is no comparison for us.
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Over the past 2 months all of my local gas stations switched to ethanol blend. It is supposed to be a max of 10% ethanol. But I have noticed a significant decrease in my mileage. I frequently make a 186 mile round trip drive in my GL 450. Virtually all highway at 70-85 mph. Over the course of dozens of trips, my usual fill after the trip had been 10 to 10.5 gallons. The last few trips with ethanol blend have consumed 11 to 12 gallons. It does not seem possible that 10% ethanol could have such an adverse effect on mileage.
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A recent study that I read stated that most will see a 5% decrease in mileage with the use of 10% ethanol
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Not true Kent, West Virginia has a state law that requires pumps dispensing ethanol to have a sticker. Some here do, and others do not. If I am wrong, please post a link to the federal mandate.
Last edited by Musikmann; Sep 2, 2008 at 10:16 PM. Reason: typo
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I believe that the actual requirement for 10% ethanol is only in certain areas of the country that are prone to pollution. It is not a nationwide federal mandate.
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From: fl
1992 500E, 2006 E500, 2007 GL 450
I may be missing something but if ethanol had no value as a fuel at all the maximum impact on would be a mileage reduction of 10%. If ethanol had only half the energy of gasoline the impact might be 5%. Most of what I have read indicated that ethanol has about 90% of the energy of gasoline which led me to believe the mileage reduction would be on the order of 1% - essentially negligible. Reductions of 5% or more in mileage which many seem to be experiencing seems impossible. I wonder what's up?
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From: Louisville, KY
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From what I understand, the ethanol blend is supposed to be cleaner burning to help ease smog. However, since it does indeed have less energy and cause you to burn more fuel overall, aren't we still polluting more than if we used straight gas and burned less of it????
Sounds like the politicians are getting kick backs to push the ethanol.
Thats why I like the diesel although I pay more per gallon than gas and more in taxes! I don't think they can screw too much more with the diesel (ULSD the latest change).
If you drive infrequently with ethanol, the fuel breaks down fairly fast and the ethanol tends to attract water. Can be a problem with filter clogs and possibly frozen fuel lines in the winter months. If you drive enough to fill once every week or two, it shouldn't be a problem.
Many older vehicles have had some serious problems with gaskets, seals, etc, breaking down in the presence of the ethanol and have done some serious carb and filter clogs. Everything from farm equipment to boats.
I seriously see no advantage to the ethanol blend.
Sounds like the politicians are getting kick backs to push the ethanol.
Thats why I like the diesel although I pay more per gallon than gas and more in taxes! I don't think they can screw too much more with the diesel (ULSD the latest change).
If you drive infrequently with ethanol, the fuel breaks down fairly fast and the ethanol tends to attract water. Can be a problem with filter clogs and possibly frozen fuel lines in the winter months. If you drive enough to fill once every week or two, it shouldn't be a problem.
Many older vehicles have had some serious problems with gaskets, seals, etc, breaking down in the presence of the ethanol and have done some serious carb and filter clogs. Everything from farm equipment to boats.
I seriously see no advantage to the ethanol blend.
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If you have a private tank, you can get tehnon-blended stuff pretty much anywhere. I have diesel and gasoline tanks and private pumps at our farm and home, and get pure non-ethanol gasoline. That is necessary because the fuel sits for several months at a time and would separate. A big problem with ethanol is that is is water-soluable and destroys marine and farm equipment gas tanks made of fiberglass and some plastics. So most distributors do have the pure stuff and will deliver it (taxed so it can be use on road). We go out of our way to avoid ethanol blends, even in our Priuses.
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From: N. Illinois, USA
2021 GLS450, 2015 E250BT 4Matic, 2007 GL320CDI, 2005 SLK350, 2001 SLK320
Ethanol returns about 65% of the fuel economy of gasoline. Since the E10 blend is 90% gas and 10% ethanol, the resulting fuel economy is 96.5% of straight gas.
(.90 x 1) + (.10 x .65) = .965
So if you get 20 mpg with gas, then you should get (20 x .965) = 19.3 mpg with a 10% ethanol blend.
To continue with the arithmetic, E85 will return 70.25% of the fuel economy of gasoline.
(.15 x 1) +(.85 x .65) = .7025
So, if a car accepts E85 (most MBs don't) then you would have to find it priced less than 70% of the price of straight gasoline to make it worth buying. And you would have to not mind filling the tank more often.
I think I'll stick with the diesel-powered engines.
(.90 x 1) + (.10 x .65) = .965
So if you get 20 mpg with gas, then you should get (20 x .965) = 19.3 mpg with a 10% ethanol blend.
To continue with the arithmetic, E85 will return 70.25% of the fuel economy of gasoline.
(.15 x 1) +(.85 x .65) = .7025
So, if a car accepts E85 (most MBs don't) then you would have to find it priced less than 70% of the price of straight gasoline to make it worth buying. And you would have to not mind filling the tank more often.
I think I'll stick with the diesel-powered engines.
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From: fl
1992 500E, 2006 E500, 2007 GL 450
[QUOTE=mbslk350;3045175]Ethanol returns about 65% of the fuel economy of gasoline. Since the E10 blend is 90% gas and 10% ethanol, the resulting fuel economy is 96.5% of straight gas.
(.90 x 1) + (.10 x .65) = .965
I have experienced about a 10% reduction in mileage. My results appear to be similar to several friends and neighbors. Letters to the editor of the local paper also indicate my experience is common and far worse than the 3.5% mileage eduction indicated by the math.
As noted above there are problems with the ethanol blend related to marine engines and to vehicles and equipment which are not used regularly in which the same fuel can be in the tank for weeks or months.
To paraphrase Mel Brooks - it's good to be a corn producer - or a lobbyist.
(.90 x 1) + (.10 x .65) = .965
I have experienced about a 10% reduction in mileage. My results appear to be similar to several friends and neighbors. Letters to the editor of the local paper also indicate my experience is common and far worse than the 3.5% mileage eduction indicated by the math.
As noted above there are problems with the ethanol blend related to marine engines and to vehicles and equipment which are not used regularly in which the same fuel can be in the tank for weeks or months.
To paraphrase Mel Brooks - it's good to be a corn producer - or a lobbyist.
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From: N. Illinois, USA
2021 GLS450, 2015 E250BT 4Matic, 2007 GL320CDI, 2005 SLK350, 2001 SLK320
I guess there's theory and then there's real life. We've had E10 blend for years (maybe decades?) here in the corn belt so I don't have any basis for comparison.
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From: Louisville, KY
2014 Black SLK 55 AMG, Black 2015 GL 550, 2011 Blue GLK 350
I also have heard the life of ethanol blended gas is 90 days before breakdown starts occuring. And the clock starts at time of mixture. Not from when you put it into your tank. So depending on how far you are from the refinery would also effect the usable life.
The math is theoretical on the effect of reduction of economy. However as one poster said above, the high tech computers sense the change in gas and change everything from timing to amount of fuel is injected to get the proper combustion. In reality, that could be anything as noted by most posters noticing about a 10 % reduction in economy.
My wife had a 2007 C 230 sport sedan that was set up for using E-85. We never put that stuff into the car. (traded it for 2008 E350 which is NOT set up for E-85)
The math is theoretical on the effect of reduction of economy. However as one poster said above, the high tech computers sense the change in gas and change everything from timing to amount of fuel is injected to get the proper combustion. In reality, that could be anything as noted by most posters noticing about a 10 % reduction in economy.
My wife had a 2007 C 230 sport sedan that was set up for using E-85. We never put that stuff into the car. (traded it for 2008 E350 which is NOT set up for E-85)
