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  • Switching to E85?

    I tried searching first but the term is only 3 letters and returns no results.

    I'm thinking about trying E85 so see if I can get a little more power from my KA. From what I've read I'd be needing to increase fuel flow about 30% just to be even with gas. My quick calculation says that the 370cc SR injectors are just about 37% bigger than the stock 270cc injectors. I have an Innovate wide-band O2, an adjustable FPR and an Apexi NEO AFC, so I should be able to tweek it in from there.

    ?

    Thanks,
    DJ
    Don Johnson (really!)
    Just so you know.

  • #2
    For my car it was EXACTLy at 25% from E10 to E85. It's more like 30% from no ethanol gasoline to E85, but everywhere I've filled up in the past 3-4 years has been 10% ethanol.

    Are you still on the stock tune? I'd say it'd be worth getting Nistune or something similar just to ditch the horrible stock timing and fuel maps. But your setup will probably work. Not perfectly, but it'll work.
    '18 Chevrolet Volt - Electric fun hatch for DD duty!


    DefSport Koni Sleeve and Spring Perch Buy!!!
    http://www.nissanroadracing.com/showthread.php?t=5902

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    • #3
      Def,
      I'm running a JWT ecu but I'm considering Nistune or similar in the near future. If it's 25% straight across from E10 that means I've got 12% left for improvements! ;-) Thanks for the info!
      DJ
      Don Johnson (really!)
      Just so you know.

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      • #4
        I have found mine to be more like 35% increase in fuel, I wouldn't be surprised if it varies depending on what region you're in though as e85 isn't necessarily 85% ethanol, it's anywhere from 70-85%. I haven't tried an NA ka on e85 but I wouldn't think you would see much gains. I'm not dogging on e85, it really woke my car up, I just don't think it would do much on an NA ka...

        EDIT- nevermind, just saw your post in the last thread, if you're just looking to squeeze that last little bit out with minimum mods allowed I'm sure you would see some differece...
        Last edited by ericb382; 07-31-2011, 11:08 PM.

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        • #5
          not trying to go off topic to much, but speaking of mixture differences, does anyone have any quick octane tests to see what we're getting locally or from a particular station?

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          • #6
            Any validity to the need to switch out rubber parts? Or is it just injectors and tune?

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            • #7
              I ran mine for about 120-150 gallons of E85 with mostly stock fuel hoses (replaced the stuff in the engine bay because it was easy to get to). Still running the hoses just fine. I would still run E85 if it were more readily available around tracks.

              BTW - I arrived at 25% by doing the stoichiometric ratios of E10 to E85. It was very very close to 25%, so I went with that much k-value change and a little change to the ign map to add about 3-4 deg at the same boost as on E10. It was FAST for a stockish SR20 with a T25 flange turbo.

              I upped the boost to around 21 psi on a GT2876R and made enough torque to slip an ACT HD clutch (I think it's rated to around 390 ft-lbs at the crank). This was around 6.5k RPM in 4th gear and climbing fast. I chilled out after that happened a few times, and the clutch returned to normal after a few dozen street miles and I'm still using it and it holds 19 psi on E10 just fine.



              Anyway, the only good thing about your plan is the "excess" injector capacity will mean you're running at a slightly lower load column than the ECU otherwise would be, which will give you more timing at the same base timing. E85 loves timing, so you'd be on the right track. You can probably tweak the distributor/CAS to get things close after that. There's still some power to really tuning it IMO, and usually big driveability gains vs. an AFC, but it'll run decent at WOT.
              '18 Chevrolet Volt - Electric fun hatch for DD duty!


              DefSport Koni Sleeve and Spring Perch Buy!!!
              http://www.nissanroadracing.com/showthread.php?t=5902

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              • #8
                Originally posted by sil8y View Post
                not trying to go off topic to much, but speaking of mixture differences, does anyone have any quick octane tests to see what we're getting locally or from a particular station?
                You can pick up a tester for measuring the actual mix ratio of gas/ethanol in E85 for less than $20. A two minute google of "Octane testers" came up with $10k for a portable unit!
                Don Johnson (really!)
                Just so you know.

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                • #9
                  all flex fuel vehicles have a sensor that tells the ECU what mix is in the tank,

                  tuning on E85 is sketchy since they can change the ratio around (since all flex fuel cars have that sensor)

                  MegaSquirt guys are working on a 0-5v sensor that can be used as an ECU input to trim out fuel for flexfuel compatibility on aftermarket ECU's
                  I am SKULLWORKS

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                  • #10
                    Originally posted by Tower240sx View Post
                    all flex fuel vehicles have a sensor that tells the ECU what mix is in the tank,

                    tuning on E85 is sketchy since they can change the ratio around (since all flex fuel cars have that sensor)

                    MegaSquirt guys are working on a 0-5v sensor that can be used as an ECU input to trim out fuel for flexfuel compatibility on aftermarket ECU's
                    Yup, Megasquirt uses a flex fuel sensor to determine whatever % of alcohal your running at the time. I know a guy who tried all kinds of mixtures to verify it's effectiveness. I think everyone's using a Ford sensor...

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                    • #11
                      Here in south florida our "e85" is more like e80-e82 with one of the $20 test kits. we have e98 for the race car and have been mixing 4 gallons of e98 to 1 gallon premium 93 octane gas and getting e89 for the street cars with the same test kit. they sell gauges like a wide band to tell you what the rating is but that like $600 for the gauge.

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                      • #12
                        I just keep an eye on the wideband, especilly close after filling up. I noticed a difference when they switched from "spring/fall" blend to "summer blend," but it wasn't so extreme that I was really worried. I just made a few slight changes to the tune. I will hopefully get a tune perfected for each blend that this station sells (I always use the same one) and just upload the new tune depending on the time of year.`

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                        • #13
                          Air/Fuel ratio for E85

                          I was just looking up heating values for a work project and noticed that ethanol stochiometric ratio is 9:1, compared to gasoline at 14.7:1. Does that mean that E85 air/fuel ratio is 9.8:1? I've got an Innovate WB02 meter but I haven't paid attention to how they work so I don't know if E85 would read the same as gasoline at the correct air/fuel ratio(?) If they measure the lean/rich conditions rather than an actual ratio wouldn't they read the same with similar tunes on either fuel? I suspect the "ratios" marked on the guage is only analagous to gasoline and meaningless for other fuels. (?)
                          Last edited by djsilver; 08-07-2011, 05:22 AM.
                          Don Johnson (really!)
                          Just so you know.

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                          • #14
                            Wideband O2 sensors measure lambda (i.e. the ratio of your current AFR to the stoichiometric AFR). They do not "know" the actual AFR, so the AFR displayed is just lambda * stoichiometric ratio.

                            For example, running a 0.8 lambda on straight gas is an AFR of 11.7. The same lambda on E85 has an AFR of ~7.8. Your wideband will display 11.7 in BOTH cases.
                            '18 Chevrolet Volt - Electric fun hatch for DD duty!


                            DefSport Koni Sleeve and Spring Perch Buy!!!
                            http://www.nissanroadracing.com/showthread.php?t=5902

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                            • #15
                              That's what I suspected. Thanks for the confirmation.
                              DJ
                              Don Johnson (really!)
                              Just so you know.

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