Close

Results 1 to 13 of 13
  1. #1
    Join Date
    Mar 2012
    Location
    Cleveland TN
    Posts
    541
    Rep Points
    554.0
    Mentioned
    16 Post(s)
    Rep Power
    6


    Reputation: Yes | No

    Questions on measuring ethanol content

    New to playing around with E85 and wanted to make sure the method I'm using is accurate. I'm using the 100ml tube where you add say 25ml of water then add the mixture in to fill it up to 100ml, shake and watch the separation line and then do basic math. I filled up a 30 gallon barrel with E85 since the nearest station is 30 minutes away. After measuring the contents of the barrel I'm coming up with E89.3 which makes me happy if it's accurate as I was afraid I might have gotten E75 or something low for the winter. The tank I already had in the car I had already adjusted to where my logs were clean but couldn't get a hose down far enough into the tank to siphon off so I had to add 6 gallons of fresh gas to get it high enough to siphon some off to test. I had a 1/4 tank and running through the testing showed by new tank was only at E12 and trying to do backward guess work I came in that I had previously only had maybe an E25 mixture in the tank.

    So my questions would basically be is this method really accurate and if so does it really only take E25 this time of year (texas in the 70's) to make the E30 Cobb mapp happy?

    Any easier way to pull fuel samples other than a cheap siphon pump as it seems tricky to get that hose down in there where it actually gets anything.

  2. #2
    Join Date
    Feb 2012
    Location
    Naples, FL
    Posts
    2,086
    Rep Points
    2,142.2
    Mentioned
    67 Post(s)
    Rep Power
    22


    Reputation: Yes | No
    Honestly, how I measure it is I know that I have a tank with x amount of fuel, if the tank is half empty I add x amount of E85, and tune the car to that amount. I always use 50% so if there is 1/4 tank i add 1/4 tank of E85.




  3. #3
    Join Date
    Mar 2012
    Location
    Cleveland TN
    Posts
    541
    Rep Points
    554.0
    Mentioned
    16 Post(s)
    Rep Power
    6



    Reputation: Yes | No
    Click here to enlarge Originally Posted by E90SoFlo Click here to enlarge
    Honestly, how I measure it is I know that I have a tank with x amount of fuel, if the tank is half empty I add x amount of E85, and tune the car to that amount. I always use 50% so if there is 1/4 tank i add 1/4 tank of E85.
    I'd rather not guess if I don't have to considering E85 fluctuates in it's mix as does normal pump gas. If the gasses didn't fluctuate that would probably be fine.

  4. #4
    Join Date
    Sep 2012
    Location
    Harrisburg
    Posts
    1,284
    Rep Points
    1,526.3
    Mentioned
    43 Post(s)
    Rep Power
    16


    Reputation: Yes | No
    Look at page 28 in the ethanol guidebook:

    www.nrel.gov/docs/fy06osti/40243.pdf

  5. #5
    Join Date
    Nov 2011
    Location
    Florida
    Posts
    904
    Rep Points
    785.6
    Mentioned
    113 Post(s)
    Rep Power
    0


    Reputation: Yes | No
    Here is another tool for whatever it is worth

    http://www.wallaceracing.com/octane-mix-calc.php

  6. #6
    Join Date
    Jun 2012
    Location
    NJ
    Posts
    4,198
    Rep Points
    1,800.2
    Mentioned
    102 Post(s)
    Rep Power
    19


    Reputation: Yes | No
    Check your E85 pump the next time you pass through. There's usually a legal disclaimer saying that the lowest the ethanol content will be is 70% (kinda like on this one):
    Attachment 22636
    COBB AP ProTune by Bren of ///Bren Tuning
    Akrapovic DP | Helix FMIC | Alpina TCM Flash | Walbro 450LPH Fuel Pump


    "The moment money becomes your motivation, you are immediately not as good as someone who is motivated by passion and internal will." -A. Senna

  7. #7
    Join Date
    Mar 2012
    Location
    Cleveland TN
    Posts
    541
    Rep Points
    554.0
    Mentioned
    16 Post(s)
    Rep Power
    6



    Reputation: Yes | No
    Click here to enlarge Originally Posted by ajm8127 Click here to enlarge
    Look at page 28 in the ethanol guidebook:

    www.nrel.gov/docs/fy06osti/40243.pdf
    Yep Page 30 is basically the same step that I was doing just different amounts of water but works out about the same. Ok so good to know I've got some E89. Next one is there an easy way to siphon? and I guess I'll have to play with the timing a bit after I get a set percentage that I'll always have.

  8. #8
    Join Date
    Mar 2012
    Posts
    303
    Rep Points
    308.2
    Mentioned
    8 Post(s)
    Rep Power
    4


    Reputation: Yes | No
    FWIW, it's ok to calculate for the minimum ethanol (E70) if your "greater-than" margin of error will end up below the E50-E60 threshold of the OEM fuel tables, the excess ethanol content from running E85 vs. E70 is just an additional power and cooling benefit.

    You're running COBB E30, which IIRC reflashes the fuel table for that map which allows for a higher margin of error.

    Basically what I'm saying is that the E30 should be safe to run up to max fuel trims which is usually E50 - E60 ethanol content (depending on fuel tables), it's just not safe to run lower than E30.
    Last edited by spool twice; 11-30-2012 at 08:26 AM.
    Loe P.
    B8.5 Audi S5 3.0"T" - GIAC stage II ECU / GIAC DSG TCU / AWE-tuning Pulley / AFe filter / 034 TBB / mod airbox / X-pipe
    - 09' E90 M3 7-DCT Interlagos Blue / Novillo Silver - gone Click here to enlarge
    [K&N filter|MS pullies|test pipes|Evolve Stg II tune/Servotronic/GTS-DCT Tune|Euro MDM]


  9. #9
    Join Date
    Sep 2012
    Location
    Harrisburg
    Posts
    1,284
    Rep Points
    1,526.3
    Mentioned
    43 Post(s)
    Rep Power
    16


    Reputation: Yes | No
    Click here to enlarge Originally Posted by brusk Click here to enlarge
    Yep Page 30 is basically the same step that I was doing just different amounts of water but works out about the same. Ok so good to know I've got some E89. Next one is there an easy way to siphon? and I guess I'll have to play with the timing a bit after I get a set percentage that I'll always have.
    I guess the page numbering of the guidebook itself is different than the pdf file. PDF page 30 is guidebook page 28. sciencelabsupplies.com has much more reasonable prices than the supplier given in the guidebook for equipment needed to test the fuel.

    I actually thought about installing some kind of fuel test fitting in the low pressure line leading to the hpfp. Possibly a tee to a ball valve. That way I could open up the valve, and cycle the fuel pump to get a sample to read.

    Spool twice,

    I do agree also with what you are saying. As long as the ethanol content of your fuel tank is in a certain range, everything should be fine. The fuel trims make this possible. However, I still think it's good to sample the tank periodically because when you fill up, you have to know the ethanol content of the current fuel to know the ethanol content of the tank once it is full. If you are estimating the current ethanol content based on past a fill up, your error could increases with each fill up. A test of the fuel in the tank would let you know exactly what the ethanol content is. Of course if you routinely run your tank down all the way before fill up, this matters much less.

  10. #10
    Join Date
    May 2012
    Location
    Jacksonville, FL
    Posts
    2,937
    Rep Points
    2,858.9
    Mentioned
    78 Post(s)
    Rep Power
    29


    Reputation: Yes | No
    Not sure if you have a spare $600 laying around, but if i ran E85 more often i think i would look into purchasing this - http://www.zeitronix.com/Products/ECA/ECA.shtml

    The analyzer is $199, and they sell the same Flex fuel sensor as the one used in Shiv's E85 kit for $359. An 8 Ft wiring harness is $29. Plop that bad boy in your glovebox and you are golden.
    2011 E90 M3 \ Melbourne Rot Metallic

    Click here to enlarge

  11. #11
    Join Date
    Feb 2012
    Location
    Naples, FL
    Posts
    2,086
    Rep Points
    2,142.2
    Mentioned
    67 Post(s)
    Rep Power
    22


    Reputation: Yes | No
    Click here to enlarge Originally Posted by lulz_m3 Click here to enlarge
    Not sure if you have a spare $600 laying around, but if i ran E85 more often i think i would look into purchasing this - http://www.zeitronix.com/Products/ECA/ECA.shtml

    The analyzer is $199, and they sell the same Flex fuel sensor as the one used in Shiv's E85 kit for $359. An 8 Ft wiring harness is $29. Plop that bad boy in your glovebox and you are golden.

    Oh thats cool... I want one now. But I wouldn't put it in the glovebox. HUD all day..




  12. #12
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,797
    Rep Points
    31,559.9
    Mentioned
    2064 Post(s)
    Rep Power
    316


    Reputation: Yes | No
    Moved to general automotive.

  13. #13
    Join Date
    Aug 2010
    Location
    Chicago Burbs
    Posts
    1,814
    Rep Points
    1,066.8
    Mentioned
    21 Post(s)
    Rep Power
    11


    Reputation: Yes | No
    Bumping and old thread, but through this might be helpful to you folks. http://www.bimmerboost.com/showthrea...etermine-Mixes
    2015 - Cayman GTS - Stock
    2011 - 335is e92 - Cobb PTF E40/Rob Beck/AR/Helix (458 rwtq and 479 rwhp) - Retired
    2007 - 911 Turbo - EP1/AMS (617 awtq and 500 awhp) - Retired
    2008 - 335i e92 - Cobb/AR/Helix/OSS (384 rwtq and 356 rwhp) - Retired
    2003 and 2005 330i/ci zhp - Stock - Retired

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •