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Alcohol in gas affects mixture

Discussion in 'How-To's / Knowledge Base' started by Bonnewagon, Jun 21, 2013.

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  1. 79wagonator

    79wagonator Greasemonkey

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    I guess I wrote it wrong, newer motors see a drop in mpg also is what I've heard from people in areas where pure gas and e10 is available
    On LI only e10 is available.
    As far as the high performance boating community, nobody likes the e10 which in my area is whats sold at the docks also.
    And being able to absorb more moisture cant be a good thing..
    I'm no scientist but Last I checked, water doesn't burn
    I drain the fuel tank in the boat at the end of every season and burn it in my truck.
     
  2. CWPottenger

    CWPottenger G-Body Guru

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    Totally agree with that statement.
     
  3. Clone TIE Pilot

    Clone TIE Pilot G-Body Guru

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    It's pretty simple, a motor set up to burn gas won't have enough compression to properly burn ethanol. If it did, it would spark knock badly running on just gas. Cliff who is one of the top Qjet guys around says ethanol leans out the fuel mixture on older engines because they are not set up to burn it. It's just 10% inert filler to a gasoline engine, so you must enrich your mixture to make up for it. Ethanol has an -OH group in its chemical formula. That OH group is IN THE FUEL, you can not get rid of this -OH group. The only way to do so is to run straight gasoline. This extra oxygen IN THE FUEL, combined with the oxygen in the air (approximatley 21% O2, 78% N2) leans out your engine if you have a carbed motor. So basically you have extra oxygen in your fuel which changes the chemical equation from stoich and causes a lean burn, which results in higher flame temps. By having this leaner mixture, your jetting would need to be a size or two richer to compensate. A perfectly running engine uses 14 parts air to 1 part fuel. If that one part fuel is 100% fuel then your ratio is a perfect 14:1 When you introduce ethanol it uses up a percentage of the 1 part fuel. For example if you are running 15% ethanol then your new ratio is leaned out to 14:0.85. Ethanol burns at a different air/fuel ratio. It takes more ethanol for the same amount of air. An E10 combo is going to take slightly more fuel than straight gas for the same amount of air.
     
  4. Bonnewagon

    Bonnewagon Comic Book Super Hero

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    Now THAT is what I was thinking. ^^^^^^^^ Thank's Clone TIE Pilot for putting it in technical terms that make sense.
     
  5. jrm81bu

    jrm81bu Comic Book Super Hero

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    Yes and no. Water in gas is a bad thing because they won't mix. The gas will float on the water and all you get out of the pickup is water. However since the alcohol in e10 will absorb the water it does get burnt because it gets all mixed together. Water is nothing more than hydrogen and oxygen, both of those elements burn when separated.
     
  6. 79wagonator

    79wagonator Greasemonkey

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    So water has no effect on the fuel you burn in your car?
    OK.
    Refer to what Clone TIE Pilot wrote above..
     
  7. jrm81bu

    jrm81bu Comic Book Super Hero

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    How is ethanol inert? You don't have to have massive compression to use it. By you first two sentences alone you, you are saying that having a flex fuel vehicle is impossible. I agree that to take advantage of the extra oxygen content you would want to add fuel. Thats exactly what running nitrous does. But 10% ethanol is no where near that. I honestly don't think that if you were using a wideband o2 that you would see any difference. Even if it did run slightly leaner the ethanol burns at a slower rate and that would negate any chance of detonation. All your math for your ratios is wrong, your are concluding that ethanol is not a fuel at all and therefore isn't a part of the ratio. I'm sorry but it is a fuel and is still a part of the ratio. Also 14.7:1 is stioch but you won't see any vehicles runnig that ratio when they are accelerating anyway. I do agree with your last sentence though, you will need more e10 to make the same power but that has nothing to do with causing detonation.
     
  8. jrm81bu

    jrm81bu Comic Book Super Hero

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    Read again. Since the alcohol absorbs the water, it is no longer is water just laying in the tank.
     
  9. 1bad79

    1bad79 Greasemonkey

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    clone has it exactly right, ethanol leans your fuel mixture out
     
  10. jrm81bu

    jrm81bu Comic Book Super Hero

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    Then explain how.
     
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