Ethanol experiences ?











Any car made after about 1990 is designed to run off E10. Pre-1990 cars, or carbureted cars in general I probably wouldn't put E10 in.
Ethanol acts as an octane booster, and is generally beneficial to high performance engines. I wouldn't worry at all about using it. You pay a hefty premium for ethanol free gasoline.
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I just wonder how we're going to do in the mileage when the increase of 15% ethanol is made. Everyone I talk to say that for every 5% of ethanol you lose about 3-5 MPG ?
But consider that for E10, Ethanol is blended at a 90% regular gasoline/10% ethanol ratio. This means the net energy loss is about 2%, and your mileage should also be roughly 2% lower.... some cars more... some less. And E15, or 15% Ethanol will result in about a 3% average lower mileage.
However, also consider that the wholesale price/gallon of ethanol runs about 20% less than wholesale price/gallon of regular gasoline. Amazing how this works, isnt it??!! Wholesale Prices for each are always volatile and can change daily/hourly, so the price relationship is not locked. But in the long run prices roughly correlate to the above relationship which effectively compensates for the lower energy value in E10.
For the same reasons, E85 mileage will be about 15% less than E10 gasoline, but price should generally reflect this same difference.
As to the concern that all gasoline will become E85, you can relax. Theres not enough corn to ever get there so will not happen any time soon. Cellulosic, maybe... but we're a long way from economically producing that much cellulosic ethanol... and its not just around the corner.
Denatured ethanol only has about about 2/3 (67.8-69.9%) of the energy content of gasoline. (78000-78300 BTU/Gal vs. 112000-115000 BTU/gal).
Updated to add denatured per C4Rider's comments in post 20. I agree that pure ethanol is not used, but rather denatured alcohol per ASTM D4806 and the energy values from the denatured alcohol are based on the Renewable Fuels Association information. There is a slight adjustment in values, but I do not see significant changes to the information I posted.
See web site http://ethanolrfa.org/page/-/RFA%20F...10.pdf?nocdn=1
E10
At a 10% ethanol to 90% gasoline (E10) the blend has 96.6% (96.8 - 97%)of the energy of pure gas. You should expect about 3.4% (3.0-3.2%) worse mileage.
Try looking at the following government EPA web site.
http://www.fueleconomy.gov/feg/ethanol.shtml
It states that E10 you should expect 3-4% worse mileage. That matches the energy content calculations.
E85
At a 85% ethanol to 15% gasoline (E85) the blend has 71.7% of the energy of pure gas. You should expect about 28.3% worse mileage.
The same web site also states that with E85 you should also expect a 25-30% drop in mileage. That matches the energy content calculations.
For other reasons, many like the ethanol. It is very good for octane and high compression/boost applications. If the car is tuned for ethanol it can run higher compression, higher boost, more ignition advance, etc and make very good power. Also if higher compression and more advance is used, the engine can become more efficient so that the loss in mpg can be reduced considerably.
However I don't like it for my cars because they are not set up specifically for ethanol and I loose mileage. I also have an old car that I am concerned with the ethanol damaging seals in the fuel system.
Last edited by QCVette; May 20, 2013 at 01:18 PM.
E10
At a 10% ethanol to 90% gasoline (E10) the blend has 96.6% of the energy of pure gas. You should expect about 3.4% worse mileage.
Try looking at the following government EPA web site.
http://www.fueleconomy.gov/feg/ethanol.shtml
It states that E10 you should expect 3-4% worse mileage. That matches the energy content calculations.
E85
At a 85% ethanol to 15% gasoline (E85) the blend has 71.7% of the energy of pure gas. You should expect about 28.3% worse mileage.
The same web site also states that with E85 you should also expect a 25-30% drop in mileage. That matches the energy content calculations.
For other reasons, many like the ethanol. It is very good for octane and high compression/boost applications. If the car is tuned for ethanol it can run higher compression, higher boost, more ignition advance, etc and make very good power. Also if higher compression and more advance is used, the engine can become more efficient so that the loss in mpg can be reduced considerably.
However I don't like it for my cars because they are not set up specifically for ethanol and I loose mileage. I also have an old car that I am concerned with the ethanol damaging seals in the fuel system.
California has been running E10 since 1995. No issues here. I had a 79 Bonneville that didn't have any changes to the fuel system that went 460 miles on the original motor before we sold it to a junk yard. And yes, we had since it was new!
My 1990 300zx ran E10 almost all its life here in Cali. It's still buzzing around here. I see it now and then.
My 1997 Trans Am (LT1) had no issues with it at all. Nor my 2002 Trans Am.
Honestly, E10 (even E15) isn't going to hurt ANYTHING at all. The only thing it could potentially hurt is rubber fuel lines, but no cars use those anymore. Since 1990, all fuel lines have been stainless steel.
Its not like ethanol-free gasoline doesn't have any additives, it just has additives that aren't ethanol. Mostly it uses MTBE instead of ethanol, and MTBE is chemically derived from Methanol, which is also an alcohol. Granted, there isn't 10% MTBE in gasoline, but E10 usually doesn't have a full 10% ethanol in it either, it is up to 10%. Yes, the ethanol does have a lower specific energy, but it also acts as an octane booster and burns faster, so it has power-providing benefits to gasoline which party make up for the lower energy.
What surprises me most is why people are so anti-ethanol. Most people on this forum would gladly pay a 10% premium to buy a U.S. made product over an imported product, but you would rather buy oil from OPEC than ethanol from a local corn farmer?
The fuel mileage disadvantage cancels out anyway, as was pointed out earlier. Ethanol is cheaper than gasoline, so whatever mileage you lose, you gain in cheaper pump prices. If you buy ethanol-free gasoline, you will end up paying more per mile on gas.
Not to mention the big push for E10 in the first place is that its been shown to significantly reduce emissions. And I'm not talking about Al Gore CO2 emissions, ethanol helps reduce NOx emissions, among other things, that produce smog and acid rain. Go spend a week in Beijing and let me know if you still think that we shouldn't try to limit smog.
If you have a 1969 vette with a 4 barrel carbureted 427, then yeah buy ethanol free gas. If you drive a C5, then don't waste your money on ethanol free gas.
E10
At a 10% ethanol to 90% gasoline (E10) the blend has 96.6% of the energy of pure gas. You should expect about 3.4% worse mileage.
Try looking at the following government EPA web site.
http://www.fueleconomy.gov/feg/ethanol.shtml
It states that E10 you should expect 3-4% worse mileage. That matches the energy content calculations.
E85
At a 85% ethanol to 15% gasoline (E85) the blend has 71.7% of the energy of pure gas. You should expect about 28.3% worse mileage.
The same web site also states that with E85 you should also expect a 25-30% drop in mileage. That matches the energy content calculations.
For other reasons, many like the ethanol. It is very good for octane and high compression/boost applications. If the car is tuned for ethanol it can run higher compression, higher boost, more ignition advance, etc and make very good power. Also if higher compression and more advance is used, the engine can become more efficient so that the loss in mpg can be reduced considerably.
However I don't like it for my cars because they are not set up specifically for ethanol and I loose mileage. I also have an old car that I am concerned with the ethanol damaging seals in the fuel system.
Federal law requires ethanol producers to add a denaturant (2-8% rate) to prevent selling/drinking the near 200 proof alcohol!! ASTM 4806 provides various authorized denaturants, the largest of which is gasoline itself. This added gasoline bumps the energy content of ‘fuel ethanol’ to the ~70+ % range vs gasoline.
This suggests a ~3% drop in mileage for E10. However, this is prior to the impact of “tuning” which reduces the loss. Although accurately identifying exact/average loss is difficult, it is implied at < 3%.
Additionally, your referenced data, though valid at the time, was completed in 2007 and now relatively dated. As you noted modern car ‘tuning’ can significantly improve mileage results, so the average impact continues to decline as we move forward, further reducing the avg loss.
Regardless, we’re told certain rubber parts/seals of older cars can be impacted by ethanol, though we've had numerous postings on this board of older cars seemingly unaffected. So the real impact appears largely variable…and certainly not absolute despite our formulas and estimates.
But one thing is certain.. everyone, including manufactures, government, insurance companies, attorneys, etc have all overstated the potential damage sufficient to minimize any and all risk/liabilities.



















