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Thread: Anyone worked with C85 fuel?

  1. #1
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    Anyone worked with C85 fuel?

    Has anyone here tuned for C85 on the LT1? I am already setup on a flex fuel tune but am curious about how I should proceed with C85. VP claims a 4% power increase and the fuel is more oxygenated.

    Other than changing the stoich, would I need to setup a separate tune for the C85 vs using the flex tables? Other than trial and error with spark, is anyone seeing more spark tolerance vs 70-85% pump E85?

    Any info would be appreciated. I have also considered giving FTW Purple or equivalent fuel a try.

  2. #2
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    Quote Originally Posted by Poppacapp View Post
    Has anyone here tuned for C85 on the LT1? I am already setup on a flex fuel tune but am curious about how I should proceed with C85. VP claims a 4% power increase and the fuel is more oxygenated.

    Other than changing the stoich, would I need to setup a separate tune for the C85 vs using the flex tables? Other than trial and error with spark, is anyone seeing more spark tolerance vs 70-85% pump E85?

    Any info would be appreciated. I have also considered giving FTW Purple or equivalent fuel a try.
    I'll tell you right now that the VPc85 is not going to be measurable with the GM flex sensor with any kind of accuracy. Its a blend with all kinds of other chemicals that will throw you off. It has some nitro in it as well and should be used for all out applications. You aren't going to be able to run more spark as once the engine is at MBT your done. That particular blend of fuel has alot of energy in it which is where the power will come from...

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  3. #3
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    Quote Originally Posted by Redline MS View Post
    I'll tell you right now that the VPc85 is not going to be measurable with the GM flex sensor with any kind of accuracy. Its a blend with all kinds of other chemicals that will throw you off. It has some nitro in it as well and should be used for all out applications. You aren't going to be able to run more spark as once the engine is at MBT your done. That particular blend of fuel has alot of energy in it which is where the power will come from...
    Thanks for the info. If the flex sensor isn't reading correctly(would it read under 85%?) Then the tune may not give full spark. I would only plan on running the C85 at the track, so it wouldn't be an issue just to setup a non-flex tune using C85 stoich for track use.

    Basically keep the same spark etc as the regular tune and still get benefits of more power from fuel alone then?

  4. #4
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    The flex fuel sensor won't read the ethanol content as will a standard tester won't either with this fuel. I would disable all the flex fuel crap and just dial in your normal tables and go to the track. Get the stoich point right and target .81-.83 lambda on that fuel.

    As far as spark; the motor has a point where spark timing is optimal (MBT) higher octane fuels allow us to get there where lower octane fuels limit you. However once you have reached that spark angle that's it. That said the advantage to fuels like this is that they store much more energy in BTU's that are releases during the combustion process. If you haven't run it yet wait until you smell it.....its from from street E85...

    EFI Performance Facility-South Florida Division
    (954) 703-5560

    SHOP TOUR!!

    www.redline-motorsports.net
    2006 ZO6 7.98@179 http://www.dragzine.com/news/video-r...ast-words-z06/
    2012 ZL1 10.22@139 LSX TV

  5. #5
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    Quote Originally Posted by Redline MS View Post
    The flex fuel sensor won't read the ethanol content as will a standard tester won't either with this fuel. I would disable all the flex fuel crap and just dial in your normal tables and go to the track. Get the stoich point right and target .81-.83 lambda on that fuel.

    As far as spark; the motor has a point where spark timing is optimal (MBT) higher octane fuels allow us to get there where lower octane fuels limit you. However once you have reached that spark angle that's it. That said the advantage to fuels like this is that they store much more energy in BTU's that are releases during the combustion process. If you haven't run it yet wait until you smell it.....its from from street E85...
    Thanks alot for the info. I am in the .83-.84 range now lambda on 70-75% crappy pump e85.

    I guess the gameplan will be to set up the track only tune without flex tables, dtc, etc and since my main spark table is setup for 93 with added spark coming from flex tables Ill just add my flex spark to the main table. Change stoich for the C and dial in lambda.

    According to what I have read about the C85 it should see about 4% power gains at same spark as pump E. IF I am understanding this correctly.

    I really appreciate the info! Trying to gain a few extra horsepower for another tenth or two on my personal best at upcoming Cecil track rental in November.