Page 1 of 2 12 LastLast
Results 1 to 10 of 20

Thread: 10% Ethanol

  1. #1
    Lifetime Member Chevy366's Avatar
    Join Date
    Oct 2006
    Posts
    1,603

    Default 10% Ethanol

    Found this on Innovate site :
    Tuning Tip: Ethanol Content

    We've had a few reports where users could not “nail down” their tune on the street with the LM-1. The AFR's would jump about 0.5 AFR across the WOT band even in the same weather conditions in the space of a few days. Instead of holding a tune, the engine seemed to slowly “yodel.”

    Naturally the first thing to blame was the LM-1. But it turned out that the users filled up at different gas stations, sometimes filling up on gas that had 10% ethanol mixed in. As expected, when Schnapps is mixed with cars, things get a little complicated.

    If ethanol (stoich AFR of 9) is mixed with gasoline (stoich AFR of 14.7) the resulting gas has a lower stoich AFR than 'pure' gasoline. As the fuel injection is tuned to mix a certain amount of fuel for a given amount of air, the resulting mixture would be leaner when using a fuel with lower stoich AFR.

    This can be calculated:

    sAFR = (%ofAdditive * sAFRadditive + (90-%ofAdditive) * sAFRgas) /100

    where:
    sAFR is resulting stoich AFR
    %ofAdditive is amount in % of mass of additive (ethanol) mixed in
    sAFRadditive is stoich AFR of additive (9 for ethanol)
    sAFRgas is stoich AFR of base gasoline (14.7)

    For a 10% mixture of ethanol to gasoline by mass the resulting stoich AFR is 14.13

    So, for an engine that's tuned to certain AFR at a certain load and RPM on straight gas, the resulting (gasoline equivalent) AFR when running the mixture can be calculated as:

    new AFR = tuned gas AFR * (gasoline stoich ratio) / blend stoich ratio

    An engine tuned to 12.5 gas AFR will run at the equivalent of 13 gas AFR with a 10% ethanol blend. This is what these people were seeing.

    Of course, when running in closed loop, the engine will run at 14.13 AFR instead of 14.7. O2 sensors (incl. widebands) don’t measure AFR, but Lambda. Lambda is defined as actual AFR/stoich AFR. It's a ratio. In closed loop part throttle the engine is just running at Lambda 1.0, regardless of fuel. The same would be true for other Lambda values when running closed loop at WOT using a wideband. The engine would run at the tuned Lambda and everything would be fine. Open loop systems would need to be retuned for alcohol blends though.

    Was curious as to anyones thoughts on it .
    Do , don't , maybe , hmmmm , ? .
    2005 1500 HD , Custom OS3 SD tune .
    2006 Trailblazer
    Dinosaurs and Plants gave their lives so that we may drive , long live fossil fuel .

  2. #2
    Lifetime Member GMPX's Avatar
    Join Date
    Apr 2003
    Posts
    13,148

    Default

    I just wish we could get more than a 10% blend out here, E85 would be nice
    I no longer monitor the forum, please either post your question or create a support ticket.

  3. #3
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Quote Originally Posted by tunedbyGM

    sAFR = (%ofAdditive * sAFRadditive + (90 - %ofAdditive) * sAFRgas) / 100

    where:
    sAFR is resulting stoich AFR
    %ofAdditive is amount in % of mass of additive (ethanol) mixed in
    sAFRadditive is stoich AFR of additive (9 for ethanol)
    sAFRgas is stoich AFR of base gasoline (14.7)

    For a 10% mixture of ethanol to gasoline by mass the resulting stoich AFR is 14.13
    TunedByGM,

    Good find, good info...

    So basically, in CL it will run at as expected (stoich, even tho stoich is different), but in OL it will run "lean"... interesting.

    The equation posted by that site has a typo: the 90 should say 100.

    Cheers,
    Joe

  4. #4
    Lifetime Member
    Join Date
    Dec 2007
    Posts
    1,143

    Default

    Quote Originally Posted by GMPX
    I just wish we could get more than a 10% blend out here, E85 would be nice
    Apparently United are now marketing E85 at a few select stations in Sydney and Melbourne. Spoke to a guy running an E85 dual fuel Ford Discovery the other day.

    Cheers, and have a nice xmas.

  5. #5
    Lifetime Member Chevy366's Avatar
    Join Date
    Oct 2006
    Posts
    1,603

    Default

    What gets me is where I live they sell E85 capable autos but there is no E85 station around . Watched a vid on Jay's Garage (www.jaylenosgarage.com) about his custom made Corvette (was at SEMA) that runs on E85 , he (Jay Leno) seems to like E85 for powering his Hot Rods .
    To political , might be good fuel , but the political crap attached is horrifying .
    Last edited by Chevy366; December 26th, 2007 at 06:05 AM.
    2005 1500 HD , Custom OS3 SD tune .
    2006 Trailblazer
    Dinosaurs and Plants gave their lives so that we may drive , long live fossil fuel .

  6. #6
    Senior Member
    Join Date
    May 2006
    Posts
    165

    Default

    I would like know how they made that corvette be flex fuel. I have my Trans Am running on E-85, but I want to be able to still use gas without retuning it. It is sometimes difficult to find an E-85 station, and it definetly wont allow for any long road trips. GM should should try makeing a few vehicles that are strictly E-85. They could bump up the compression to 13:1 crank up the timing and make a pretty powerfull car.
    2002 ws6 stock short block
    GMPP cnc LS6 Heads 11.4:1 cr
    .576 i .581 e 116 lobe
    D1SC @ 10#
    723 rwhp 654 rwtq on E-85

  7. #7
    Lifetime Member Chevy366's Avatar
    Join Date
    Oct 2006
    Posts
    1,603

    Default

    Contact Jay Leno through his website , he is a gear head , he or someone that works for him may explain how they made the Corvette E85 friendly .
    I think a the start of the video he explains who did the conversion for him and go to their website .

    Don't remember what company had the duel injector set up , but stated you could drive to the track on gas then switch to Ethanol at the track , weird .
    2005 1500 HD , Custom OS3 SD tune .
    2006 Trailblazer
    Dinosaurs and Plants gave their lives so that we may drive , long live fossil fuel .

  8. #8
    Lifetime Member Garry's Avatar
    Join Date
    Jun 2006
    Posts
    649

    Default

    Germany has passed a law (or are planing to) that will increase the current 5% Ethanol in regular and premium fuel to 10% from 1/1/2009. Only the highest grade fuel will remain at 5%, due to the fact that many (most?) older cars haven't been approved for running on anything higher than 5%.
    I wonder, is the basis for this just the AFR changing, or are there any other reasons for not being able to run on 10% Ethanol? (like gaskets being damaged etc.)
    So, all anybody with EFILive (or other tuning software) would need to do is change the AFR settings?
    Garry Glendown * '17 Fifty 2SS MT * 99 Firehawk Convertible (for sale)

  9. #9
    Lifetime Member TAQuickness's Avatar
    Join Date
    Jan 2005
    Posts
    2,940

    Default

    Older systems will suffer as Ethanol, alcohol rather, absorbs water, and when combined with H2O, is corrosive. The newer flex fuel systems have plumbing designed to resist the corrosive effects of Ethanol. I'm not sure how OEM's off set the corrosion in the cylinders though.

    Lot's of spun marketing with Ethanol.

    TunedbyGM - Good find and thanks for sharing.


  10. #10
    Lifetime Member Garry's Avatar
    Join Date
    Jun 2006
    Posts
    649

    Default

    Would be nice to know which parts of an LS1 would need replacement with a higher percentage of Ethanol ...
    Garry Glendown * '17 Fifty 2SS MT * 99 Firehawk Convertible (for sale)

Page 1 of 2 12 LastLast

Similar Threads

  1. I might mix water with fuel. The ethanol manuall
    By 98 tigershark in forum General (Petrol, Gas, Ethanol)
    Replies: 0
    Last Post: September 11th, 2009, 03:08 PM
  2. Ethanol Injection
    By 4ethanol in forum Duramax 06 LLY / 06+ LBZ & LMM
    Replies: 6
    Last Post: April 23rd, 2008, 10:09 AM
  3. AFR Adjustment for 10% Ethanol
    By Chalky in forum General (Petrol, Gas, Ethanol)
    Replies: 9
    Last Post: November 19th, 2007, 02:33 PM
  4. Ethanol
    By Chevy366 in forum General (Petrol, Gas, Ethanol)
    Replies: 3
    Last Post: February 22nd, 2007, 12:25 PM
  5. Ethanol Fuel
    By oztracktuning in forum General (Petrol, Gas, Ethanol)
    Replies: 6
    Last Post: April 28th, 2006, 03:24 AM

Posting Permissions

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