Air Fuel Ratio F2 427sbf On E85

Discussion in 'General Supercharger Discussion' started by Sbfguy, Sep 27, 2015.

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  1. Sbfguy

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    Hi I have an f2 on a 427sbf on the dyno and its seems very lean going by the afr numbers I have read . It has a C&S dominator on it and on a pull from 4000 to 5500 it stays in the 8.6 range
    It has plenty of fuel 7 pounds at idle and rises 1 to 1 per pound of boost as it should
    Should I be chasing 7.4/7.6@wot ? It doesn't seem overly happy where it is. Using a fast alchohol Afr meter
    Thanks
     
    Sbfguy, Sep 27, 2015
    #1
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  2. SCF/HAIC Staff Member Admin

    Yes, that's too lean, you're above .85 lambda, you want it closer to .78 lambda with E85 that would be afr of 7.61.

    Did you test the E85 before hand to know the alcohol ratio?
     
    SCF/HAIC, Sep 27, 2015
    #2

  3. Sbfguy

    I
    No I didn't test this lot but Iv tested it from this supplier plenty of times before and it's always 85
     
    Sbfguy, Sep 27, 2015
    #3

  4. SCF/HAIC Staff Member Admin

    Ok, was just wondering how you got lucky and didn't cause a problem with it that lean under boost. If it had more gas in it, the reading wouldn't be as lean which is I mentioned it. :
     
    SCF/HAIC, Sep 27, 2015
    #4

  5. Sbfguy

    Here's a plug no sign of detonation

    image.jpg #ad
     
    Sbfguy, Sep 28, 2015
    #5

  6. Sbfguy

    .

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    Sbfguy, Sep 28, 2015
    #6

  7. vinces427bb Staff Member

    you need it to runn fatter :blackalien:
    with the F2 it doesn't appear to be pushing alot of boost at that rpm?
    how much boost on that run?
    how much are you planning on running when the tune is corrected?:eek:
     
    vinces427bb, Sep 29, 2015
    #7

  8. Sbfguy

    From memory that was around 10 pounds
    Threw some more jet at it and richened it up a little
    Did another light pull. It still stumbled a little loading in and blew the spark out at 5900 with 14 pounds of boost and started popping. Ran out of time so will throw some more fuel at it and shut the plug gap and try again image.jpg #ad
     
    Sbfguy, Sep 29, 2015
    #8

  9. Sbfguy

    With the pullies that are currently on it we should see 20-22 psi around 7200
    The other pullies I have should go around 28 psi
     
    Sbfguy, Sep 29, 2015
    #9

  10. vinces427bb Staff Member

    can you post the rest of the screen?
    that is looking impressive :woot:
     
    vinces427bb, Sep 29, 2015
    #10

  11. SCF/HAIC Staff Member Admin

    Definitely!
     
    SCF/HAIC, Sep 29, 2015
    #11

  12. vinces427bb Staff Member

    what gaps have you tried?
    down to 0.025-0.030" yet
     
    vinces427bb, Sep 29, 2015
    #12

  13. Sbfguy

    Plugs are currently at .032. C&S has advised to run .024
     
    Sbfguy, Sep 29, 2015
    #13

  14. Sbfguy

    image.jpg #ad
     
    Sbfguy, Sep 29, 2015
    #14

  15. Sbfguy

    Still having problems
    Struggles to load then pops and shuts down

    image.jpg #ad
     
    Sbfguy, Oct 2, 2015
    #15

  16. vinces427bb Staff Member

    what ignition system, coils, plugs???
    still wants more fuel??
    what plugs have been recommended if not running them now @ 0.024"gap???:blackalien:
     
    vinces427bb, Oct 2, 2015
    #16

  17. Sbfguy

    Power grid. With 7 amp box
    Plugs are ngk R5671a-8 had -9 in it
    Gapped to .024
     
    Sbfguy, Oct 3, 2015
    #17

  18. SCF/HAIC Staff Member Admin

    Have you done a vacuum leak and boost leak test?
     
    SCF/HAIC, Oct 3, 2015
    #18

  19. Sbfguy

    Sorted the issue. Put an adjustable rotor button on and phased it. And image.jpg #ad
    set plugs at .016. Maxed the current Dyno out. It only has a 1000ftlb billet break and we didn't want to risk hurting it or the engine.
    I'll put it on a 902 soon and finish the tune
     
    Sbfguy, Oct 3, 2015
    #19
    vinces427bb likes this.

  20. vinces427bb Staff Member

    great update,:blackalien:

    what car/truck are you going to run this in??o_O
     
    vinces427bb, Oct 3, 2015
    #20
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