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Thread: E85 & 93oct Mixture?

              
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    E85 & 93oct Mixture?

    So I've been running e85 (approx e35 mixture) for the past month or so.

    My question is in regards to mixing the two fuel types.

    Since e85 is about 33% lighter or less dense then regular fuel how does it act in your fuel tank?

    Let say your car has been sitting for a few days/weeks, etc... does the regulat gas settle to the bottom and the e85 rise to the top? (separation to some extent)

    If it does, would that mean towards the bottom of your tank (close to E) you'd be running a higher concentration of e85?

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    When you are parked for an extended period of time, maybe it separates. Once you drive it mixes all back up though

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    Id assume its soluble with each other and they don't separate. Just guessing.

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    why hasnt anyone thought of this until now ??
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    E85 itself is still 15% petrol, i don't believe it separates inthe underground tanks?

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    They blend & if you let it sit idle for weeks, then it's likely that it would separate. Think of it this way: why doesn't E85 separate in the underground tanks at gas stations? It's cause anytime somebody pumps a couple gallons, the entire mixture gets agitated (maintaining an equal blend).
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    E85 already has gasoline in it so if this was a problem I'd take it we would have seen it surface by now. They seem to mix without issue.

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    if you're worried about it, take the gasoline out of the e85 and leave only the ethanol.

    heres how I do it:

    you kno that gasoline burns at a rate of 1 gallon every 40 seconds
    ethanol burns SLOWER at a rate of 1 gallon every 1min 6 secs

    i fill an open top 55 gal drum with e85 and light it on fire

    since theres around 9 gallons of that mix that is gasoline and ethanol free, you say 9 times 40 sec is : 6 min!

    let it burn for 6 min, put it out with an extinguisher (or 2) and pump it out with a filter to avoid the residue.

    now you have 100% ethanol and no "un mixing" worries
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    ^ Ya, that, or get E100... not as exciting though. And you don't get to play with a fire extinguisher or DIY like a man.

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    real talk^

    or just roll the dice


    ORRR put a mixer in your tank.

    or don't be daft and do what you do
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    http://answers.yahoo.com/question/in...7051008AAwu6zE

    Click here to enlarge Originally Posted by benzy89 Click here to enlarge
    This quote is hidden because you are ignoring this member. Show Quote
    They blend & if you let it sit idle for weeks, then it's likely that it would separate. Think of it this way: why doesn't E85 separate in the underground tanks at gas stations? It's cause anytime somebody pumps a couple gallons, the entire mixture gets agitated (maintaining an equal blend).
    I thought it was mixed at the pump? Maybe that isn't all the time... hmmm.

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    Click here to enlarge Originally Posted by Ak335i Click here to enlarge
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    i fill an open top 55 gal drum with e85 and light it on fire
    LMAO

    Back on topic, are there no chemists on Bimmerboost?

    I know gasoline (octane and heptane) is not polar. I believe ethanol is (dipole moment of about 1.6 or 1.7). I don't see how they can't separate, but I'm an engineer, not a chemist.

    [EDIT] Guess I should have followed the link in post 11 before posting.

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    After talking with my girlfriend (chemist) and doing some more reading, I think the biggest problems are going to be temperature and water content.

    As the temperature decreases, the amount of ethanol that is able to be in solution with the gasoline will decrease. As water content increases, the polar nature of ethanol will cause it to be attracted to the water, which causes the phase separation you hear about concerning ethanol. The amount of water that can be present before phase separation occurs drops with temperature as well. Once phase separation has occurred, it cannot be undone without separating the gasoline from the phase separated ethanol, distilling the ethanol and adding it back to the gasoline. Ethanol is hydrophilic, so it will attract water from the air.

    This appear extremely relevant, but I don't have time to read it right now:
    http://nvlpubs.nist.gov/nistpubs/jre...n5p693_A2b.pdf

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    For what is worth BMW announced the newly government approved E15 will void its warranty.
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    Click here to enlarge Originally Posted by ajm8127 Click here to enlarge
    This quote is hidden because you are ignoring this member. Show Quote
    After talking with my girlfriend (chemist) and doing some more reading, I think the biggest problems are going to be temperature and water content.

    As the temperature decreases, the amount of ethanol that is able to be in solution with the gasoline will decrease. As water content increases, the polar nature of ethanol will cause it to be attracted to the water, which causes the phase separation you hear about concerning ethanol. The amount of water that can be present before phase separation occurs drops with temperature as well. Once phase separation has occurred, it cannot be undone without separating the gasoline from the phase separated ethanol, distilling the ethanol and adding it back to the gasoline. Ethanol is hydrophilic, so it will attract water from the air.

    This appear extremely relevant, but I don't have time to read it right now:
    http://nvlpubs.nist.gov/nistpubs/jre...n5p693_A2b.pdf
    I won't trust anything your girlfriend told you until I see what she looks like.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
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    I won't trust anything your girlfriend told you until I see what she looks like.
    Agreed.
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    This quote is hidden because you are ignoring this member. Show Quote
    I won't trust anything your girlfriend told you until I see what she looks like.
    I guess you will never be able to trust her then, because the last thing I'd do is put a picture of her on this site.

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    Click here to enlarge Originally Posted by ajm8127 Click here to enlarge
    This quote is hidden because you are ignoring this member. Show Quote
    I guess you will never be able to trust her then, because the last thing I'd do is put a picture of her on this site.
    I do not blame you one bit.

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    2 out of 2 members liked this post. Reputation: Yes | No
    After reading the study linked to above authored by Bridgeman and Querfeld, four factors come into play concerning ethanol in solution with gasoline:

    1. The temperature of the solution. Lower temperatures results in a higher likelihood of separation.

    2. The water content of the solution. More water results in a higher likelihood of separation.

    3. The concentration of ethanol to gasoline. More ethanol results in a LOWER likelihood of separation

    4. The gasoline used. Different crude makes different gas, and this has an effect on the ability of gas to hold ethanol (and water if present) in solution.

    The third point was particularly interesting. Basically, a mixture of E10 would be more likely to separate than a mixture of E35. Considering the ethanol added to gasoline is anhydrous to begin with, I think it is safe to conclude that if E10 doesn't separate, then E35 won't either, all else being equal.

    The study, from 1933, does note that additional additives to gasoline may decrease the likelihood of separation for a given amount of ethanol and water in solution with the gas. Gas formulations have surely changed since 1933, and probably have an ability to keep more ethanol in solution due to additives versus gas from 80 years ago, before E10 was widely used.

    I think the data, notably the fact that E10 will separate at a lower temperature than a solution with a higher ethanol percentage, proves that if you feel safe letting your car sit with E10 in the tank, a tankful of E35 should only be less likely to separate.

    The only problem would be water. ASTM D 4806 limits water in the ethanol used for motor fuels to 1% by volume. I've read that water contamination is not really a modern problem because gas distributors have corrected storage tank problems leading to water getting into the tank. Furthermore, even if the ethanol contained 1% water, it is mixed with 15% gas at E85, and then the ethanol percentage is further reduced when mixed with gas to achieve E30 or whatever is used in your car. You can be sure that the gasoline will not have any water in it, so a mixture of 99% ethanol and 1% water (the maximum allowable by ASTM D 4806) yields a sample with only 0.5% water at an E50 concentration, and lower water percentages for lower ethanol concentrations (E30 for instance).

    If you are concerned about a given sample of an ethanol and gasoline solution, put it in the freezer. Residential freezers are supposed to maintain at or below 0 F. Most overnight low temperatures are not even this low, so if it doesn't separate in the freezer, it won't in your car either. If you suspect separation, a simple test using water soluble food coloring will reveal if water is the culprit. If water is present, the coloring will go into solution with it. If water is not present, the coloring will not mix at all, and should fall to the bottom of the sample. The sample may need mixed after the coloring is added, and then settling time may be necessary as well. I have never tried this personally.

    In conclusion, separation of the ethanol and gas blend in your fuel tank is not likely, but the chance of separation increases in colder temperatures and with more water in the fuel. The chance of separation decreases as the percentage of ethanol in the solution increases. When in doubt, put a sample in the freezer, and if it appears cloudy after cooling, add water soluble food coloring to confirm the presence of water. However, water contamination is not really a problem any more, so you should be good under more conditions.

    Here is another interesting document. Keep in mind it was written by an employee of Sta-bil, so if you see recommendations to use that product, you'll know why.
    http://www.goldeagle.com/UserFiles/f...ed_Gasline.pdf

    This is my analysis and is not the word of God. If you see a mistake, lets talk about it. However, this information reflects the knowledge I have gained from reading about the use of ethanol in motor vehicles, and is accurate as far as I know.

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    Here's another thought evaporation. How long does it have to sit in the car to worry about anything escaping or end up going through the evap system.

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    this is a really nerdy post, but i hope you find your answer




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    Click here to enlarge Originally Posted by ajm8127 Click here to enlarge
    This quote is hidden because you are ignoring this member. Show Quote
    After reading the study linked to above authored by Bridgeman and Querfeld, four factors come into play concerning ethanol in solution with gasoline:

    1. The temperature of the solution. Lower temperatures results in a higher likelihood of separation.

    2. The water content of the solution. More water results in a higher likelihood of separation.

    3. The concentration of ethanol to gasoline. More ethanol results in a LOWER likelihood of separation

    4. The gasoline used. Different crude makes different gas, and this has an effect on the ability of gas to hold ethanol (and water if present) in solution.

    The third point was particularly interesting. Basically, a mixture of E10 would be more likely to separate than a mixture of E35. Considering the ethanol added to gasoline is anhydrous to begin with, I think it is safe to conclude that if E10 doesn't separate, then E35 won't either, all else being equal.

    The study, from 1933, does note that additional additives to gasoline may decrease the likelihood of separation for a given amount of ethanol and water in solution with the gas. Gas formulations have surely changed since 1933, and probably have an ability to keep more ethanol in solution due to additives versus gas from 80 years ago, before E10 was widely used.

    I think the data, notably the fact that E10 will separate at a lower temperature than a solution with a higher ethanol percentage, proves that if you feel safe letting your car sit with E10 in the tank, a tankful of E35 should only be less likely to separate.

    The only problem would be water. ASTM D 4806 limits water in the ethanol used for motor fuels to 1% by volume. I've read that water contamination is not really a modern problem because gas distributors have corrected storage tank problems leading to water getting into the tank. Furthermore, even if the ethanol contained 1% water, it is mixed with 15% gas at E85, and then the ethanol percentage is further reduced when mixed with gas to achieve E30 or whatever is used in your car. You can be sure that the gasoline will not have any water in it, so a mixture of 99% ethanol and 1% water (the maximum allowable by ASTM D 4806) yields a sample with only 0.5% water at an E50 concentration, and lower water percentages for lower ethanol concentrations (E30 for instance).

    If you are concerned about a given sample of an ethanol and gasoline solution, put it in the freezer. Residential freezers are supposed to maintain at or below 0 F. Most overnight low temperatures are not even this low, so if it doesn't separate in the freezer, it won't in your car either. If you suspect separation, a simple test using water soluble food coloring will reveal if water is the culprit. If water is present, the coloring will go into solution with it. If water is not present, the coloring will not mix at all, and should fall to the bottom of the sample. The sample may need mixed after the coloring is added, and then settling time may be necessary as well. I have never tried this personally.

    In conclusion, separation of the ethanol and gas blend in your fuel tank is not likely, but the chance of separation increases in colder temperatures and with more water in the fuel. The chance of separation decreases as the percentage of ethanol in the solution increases. When in doubt, put a sample in the freezer, and if it appears cloudy after cooling, add water soluble food coloring to confirm the presence of water. However, water contamination is not really a problem any more, so you should be good under more conditions.

    Here is another interesting document. Keep in mind it was written by an employee of Sta-bil, so if you see recommendations to use that product, you'll know why.
    http://www.goldeagle.com/UserFiles/f...ed_Gasline.pdf

    This is my analysis and is not the word of God. If you see a mistake, lets talk about it. However, this information reflects the knowledge I have gained from reading about the use of ethanol in motor vehicles, and is accurate as far as I know.
    This forum makes me beam with pride from time time.

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    I've mixed 93 and e85 (e30 for Cobb OTS race maps) mix and when I get to 2-3 gallons left in the tank I start throwing fuel codes. So now, I have to remind myself to either switch maps or throw more mix when I get below 4 gallons.

    Can anybody explains why this happens? The fuel in the tank is supposed to be mixed but obviously something isn't right. Again it only happens when fuel gets low and I ran the tank low a few times just to verify.

    I know there was a big debate over on the other forum (maybe it was this one) about the flex fuel monitor, but to me, this is where such a device would shine.

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    Click here to enlarge Originally Posted by Square&Level Click here to enlarge
    This quote is hidden because you are ignoring this member. Show Quote
    I've mixed 93 and e85 (e30 for Cobb OTS race maps) mix and when I get to 2-3 gallons left in the tank I start throwing fuel codes. So now, I have to remind myself to either switch maps or throw more mix when I get below 4 gallons.

    Can anybody explains why this happens? The fuel in the tank is supposed to be mixed but obviously something isn't right. Again it only happens when fuel gets low and I ran the tank low a few times just to verify.

    I know there was a big debate over on the other forum (maybe it was this one) about the flex fuel monitor, but to me, this is where such a device would shine.
    Which fuel codes did you usually throw when you are low? Because I usually wait until its low as well and I don't throw fuel codes...

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    Click here to enlarge Originally Posted by RnmEvo9 Click here to enlarge
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    Which fuel codes did you usually throw when you are low? Because I usually wait until its low as well and I don't throw fuel codes...
    p2aaf
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