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    Comments about this data plot - AFR danger

    I have some personal thoughts about what I'm seeing here, but I'm hoping to get some comments about this tune.

    2007 997 Turbo with ECU + Exhaust/Filter.

    94/91 50/50 mix.

    About 11K on the odometer, tune was done at 7K.

    Thoughts.

     

     


    Re: Comments about this data plot - AFR danger

    Bob, no answer, just "newbie's" question here: Are you referring to the saw tooth pattern of the torque curve?
    I am calling a flutter.  

    Kidding aside -- is it not the clutch slipping? Or I assume from title of thread and the AFR curve, something "bad" happens at 5400 rpm? The sudden drop implying something "mechanical," not software related?


    --
     

    Regards,
    Can
    997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


    Re: Comments about this data plot - AFR danger

    cannga:

    Bob, no answer, just "newbie's" question here: Are you referring to the saw tooth pattern of the torque curve?
    I am calling a flutter.  

    Kidding aside -- is it not the clutch slipping? Or I assume from title of thread and the AFR curve, something "bad" happens at 5400 rpm? The sudden drop implying something "mechanical," not software related?

     

    The AFR curve represents the air/fuel ratio, which suddenly gets very rich at around 5400 rpm. This will have been determined by the injection mapping, so it is software-related.

    This engine is liquid-cooled, but I didn't think that this implied that you had to use fuel to cool it. Smiley

     


    --

    fritz


    Re: Comments about this data plot - AFR danger

    The plot comes from a friend who recently purchased my 997TT - I'm in the process of sorting things out. I was quite surprised at the results of the dyno. I suggested changing plugs and coils, then rerunning the dyno with 94.

    More to come...


    Re: Comments about this data plot - AFR danger

     I think your car is running way to rich,I would prefer around 11.8 - 12/1


    Re: Comments about this data plot - AFR danger

    fritz:
    cannga:

    Bob, no answer, just "newbie's" question here: Are you referring to the saw tooth pattern of the torque curve?
    I am calling a flutter.  

    Kidding aside -- is it not the clutch slipping? Or I assume from title of thread and the AFR curve, something "bad" happens at 5400 rpm? The sudden drop implying something "mechanical," not software related?

     

    The AFR curve represents the air/fuel ratio, which suddenly gets very rich at around 5400 rpm. This will have been determined by the injection mapping, so it is software-related.

    This engine is liquid-cooled, but I didn't think that this implied that you had to use fuel to cool it. Smiley

     

    Thanks Fritz. The AFR's stair step drop looks so much like something mechanical just "snaps," but I see what you mean. What do you think of the saw tooth pattern of the power curve? I wonder if this is the cause of the AFR dumping later as engine RPM climbs?

    Bob, you still have that spare ECU? How about switching to stock ECU and re-run the data logging? Wouldn't this be the easiest diagnostic step?


    --

    Regards,
    Can
    997 Turbo + Bilstein Damptronic "Stage 2" ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )


     
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