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  1. #1
    pwc4life's Avatar
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    Question Is E85 right for me?

    I'm kicking around the idea of switching to E85, but am not sure if it's right for me. It's readily available in my area and currently $1.66/gal versus $2.75/gal for 93 octane gas. Local station claims a minimum of 70% ethanol in their blend, but I need to verify.

    Setup is in my signature. ET18 ski with a Dean's Team tune and all the necessary supporting mods. For fuel delivery it has a Riva fuel rail, 1000cc (100#) injectors, 340LPH fuel pump, and rising rate fuel pressure regulator. Will E85 on this setup require any other changes to my fuel system?

    It's a recreational ski, but does not go on long rides and is only used for 15-20 hours per year, so I am not concerned about the rate of fuel consumption. My biggest concern is the ski sits on a hoist 24/7 throughout the summer months. Is this a deal breaker given the fact that E85 is a hygroscopic fuel?

    *EDIT: Forgot to ask what type of gains, if any, can I expect from using E85 versus 93 octane gas for my setup when tuned accordingly?

    Thanks in advance!
    Last edited by pwc4life; 08-03-2020 at 10:12 AM.


  2. #2

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    Originally Posted by pwc4life
    I'm kicking around the idea of switching to E85, but am not sure if it's right for me.

    Thanks in advance!



    If you’re not going to run your Jetski very often, about 20 hours a year, why not just use 93 octane?
    You will only get the benefits of e85, is when you have a particular tune for it and higher compression pistons and more timing. Because e85 is so hydroscopic and the ethanol content varies, you will constantly be tuning and your performance will be inconsistent.
    Don’t forget that flex fuel vehicles have oxygen sensors inputs to their ECU and can adjust the air fuel ratio and timing, a JetSki cannot. That’s why you will always be tuning.
    Now if you have a drum of ethanol fuel and its content is consistent, then you would benefit if your tune is set up for it.

    take care
    CJ

  3. #3
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    Quote Originally Posted by cjk6119 View Post
    Originally Posted by pwc4life
    I'm kicking around the idea of switching to E85, but am not sure if it's right for me.

    Thanks in advance!



    If youíre not going to run your Jetski very often, about 20 hours a year, why not just use 93 octane?
    You will only get the benefits of e85, is when you have a particular tune for it and higher compression pistons and more timing. Because e85 is so hydroscopic and the ethanol content varies, you will constantly be tuning and your performance will be inconsistent.
    Donít forget that flex fuel vehicles have oxygen sensors inputs to their ECU and can adjust the air fuel ratio and timing, a JetSki cannot. Thatís why you will always be tuning.
    Now if you have a drum of ethanol fuel and its content is consistent, then you would benefit if your tune is set up for it.

    take care
    CJ
    Why switch? First, as mentioned in the OP, the price per gallon is 30-40% cheaper than 93 octane gas in my area. I know that fuel consumption with E85 will be 20-30% higher. So from a financial standpoint I'm coming out ahead. Second, it has an octane rating of 105, but due to it's ability to burn cooler than gas it behaves like it has an even higher octane rating, so once tuned for it I should be able to make more power. How much more power is one of my questions. I saw one post from Motec Pete years ago that indicated up to 500rpm when tuned accordingly. This is substantial. Is it typical of what those running reflashes from Dean, Riva, etc. have seen once tuned accordingly for E85?

    I don't understand why high compression pistons would be required for E85 as you stated. Can you please explain?

    Regarding the ethanol content varying I believe this is over the course of the year due to summer vs winter blends. I've seen some members indicate that when checking their local stations they've actually been pretty consistent during the summer. That said, it would be worth monitoring. Know that we've also had members report getting gasoline with lower than advertised octane and ruining motors. That's a chance you take regardless of where the fuel is from if you're not always checking it.

    I don't understand the point you're making with the O2 sensors and the skis inability to adjust for AFR on its own. Same issue exists with gasoline. I have an RRFPR on the ski and a wideband. Constantly monitor my AFR and if the weather changes enough to require an adjustment I do so.

  4. #4

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    After saying you need higher compression pistons, I see you have acomplished that with a ET18 wheel.
    Ether higher compression pistons or more boost, you are increasing the compression ratio to take advantage of E85's higher octane rating.


    e85 is hard on valve stems, rings, and bearings then Gasoline. E85, is long accepted as more corrosive to rubber and other engine components than gasoline. e85 has an abrasive quality which takes a much quicker toll on rings, valve stems,
    cylinders, fuel pumps, and bearings. e85 is very corrosive to some metals.
    You also dont want high concentration of E85 sitting in your fuel lines
    / mess up in your injectors it will corrode / clog them. Recommend not letting sit for more than a week.

    What kind of savings are you going to have if you just put only 20 hours on the ski with a price differential between $1.66 for e85 to $2.75 for 93 octane... works out about $85.00 a season. no big savings there ....

    To get any benefits from e85 you need a specific tune for it. $550.00 there goes your saving to run e85

    Take Care
    C J
    Last edited by cjk6119; 08-03-2020 at 01:54 PM.

  5. #5
    pwc4life's Avatar
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    Quote Originally Posted by cjk6119 View Post
    e85 is hard on valve stems, rings, and bearings then Gasoline. E85, is long accepted as more corrosive to rubber and other engine components than gasoline. e85 has an abrasive quality which takes a much quicker toll on rings, valve stems,
    cylinders, fuel pumps, and bearings. e85 is very corrosive to some metals.
    You also dont want high concentration of E85 sitting in your fuel lines
    / mess up in your injectors it will corrode / clog them. Recommend not letting sit for more than a week.
    Is anyone who has ran or is currently running E85 in their ski actually incurring any of these issues?

  6. #6
    Bob 1tommygunner1927's Avatar
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    I suggest using non-ethanol 92 octane fuel mixed with 8 ounces of Torco (unleaded) to 5 gallon jug of fuel. The effective octane rating is approximately 95-96 octane, and you will have none of the long term storage issues of ethanol laced fuels!

  7. #7

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    Quote Originally Posted by 1tommygunner1927 View Post
    I suggest using non-ethanol 92 octane fuel mixed with 8 ounces of Torco (unleaded) to 5 gallon jug of fuel. The effective octane rating is approximately 95-96 octane, and you will have none of the long term storage issues of ethanol laced fuels!
    I would advise against using E85 in any engine that is not used daily and in any engine not specifically rated for E85. Ethanol separates and water forms as ethanol gas ages. For jetski, boat, lawn mower, chain saw, snow machine, generator, pressure washer, etc. use non-ethanol if possible.

  8. #8
    pwc4life's Avatar
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    Quote Originally Posted by bizeagle View Post
    I would advise against using E85 in any engine that is not used daily and in any engine not specifically rated for E85. Ethanol separates and water forms as ethanol gas ages. For jetski, boat, lawn mower, chain saw, snow machine, generator, pressure washer, etc. use non-ethanol if possible.
    How fast does it separate? How long can it sit in a gas tank before it becomes detrimental to engine performance? Have you ran it in your ski when tuned accordingly for it?

  9. #9

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    Quote Originally Posted by pwc4life View Post
    How fast does it separate? How long can it sit in a gas tank before it becomes detrimental to engine performance? Have you ran it in your ski when tuned accordingly for it?
    From what I have read, ethanol begins breaking down between 2-3 weeks. However, do you really know how long it has been since the fuel was mixed and transported to the place where you bought it. There are good reasons that most marinas sell non-ethanol, if they can get it. Secondly, the issue goes beyond just the separation of ethanol from gasoline. E85 rated fuel systems use materials that are designed to resist ethanol as ethanol will break down many types of polymers and metals. Water vapor combines with alcohols like ethanol. So, the H2O vapor in the air within your tank is attracted to the ethanol and gets into your fuel (a full tank means less air/ less H2O vapor).

    Third, ethanol produces less energy per volume than does gasoline, which explains why fuel consumption increases as more ethanol is added to the blend. You need to burn more fuel with E85 to generate the same energy that gasoline does. BTW, the alcohol fuel that goes into drag race engines is methanol, not ethanol (nitro/methane). Methanol actually produces more energy per volume than gasoline. Ethanol is far less toxic than methanol and it has a lower flashpoint (less volatile).

    So what is to gain with E85? Lower emissions and a lower price per gallon but not better fuel economy because you have to burn more of it. So the price/ gallon benefit is offset because you burn more fuel.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by bizeagle; 08-03-2020 at 05:23 PM.

  10. #10
    IMO its not a good bang for your buck meanwhile you still have enough octane with pump gas to make power other much easier ways.If done correctly you can easily spend over a grand between tuning and a proper fuel system to support ethanol.Then you have to worry about its corrosiveness and carry jugs of it with you in case its not available where ever you travel.The gains we have seen with it back to back with no other changes is really only about 150 rpms.When E85 usage really starts to make sense is when you need more octane to run other much bigger things that are going to make you alot more power.I would say converting to E85 becomes a good value mod when your trying either to run high compression or a wheel that is bigger than 23 psi.Unless your at the point I wouldnt mess with it just yet

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