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Thread: Transient: Fuel from Wall?

  1. #1
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    Transient: Fuel from Wall?

    I've been searching for an explanation to what this "Fuel from Wall Stabl." does, and have not had much luck. Help menu is blank.

    It may just be my imagination, but moving this value from 1.0 to 2.0 seamed to have reduced a mild low rpm/low load surge I have been trying to dial out.

    I don't like changing things, just for the sake of experimentation, and sure would like to know what this does. Anyone know??
    When arguing with an idiot, make sure he isn't doing the same thing....

  2. #2
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    My 05 LS2 factory map has that set to 2 from the start.
    2018 Infiniti Q60s


    2004 350z/LS2: ERL 434ci, 11.8:1,TFS245cc,262/266@113+3,Fast102,NX 102 plate,60#injectors/return w/twin 255s
    Old setup: CNC'd317s, Fast 102, 228/228@114, PT88,83#injectors/full return system. 10.84@138

  3. #3
    Advanced Tuner Redline MS's Avatar
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    These tables are incorporated into the calibration to tell the PCM basically how to deal with fuel that clings to the intake port and doesnt immediately make it into the combustion chamber. Mostly an emission item but usefully in controlling accelerator pump shot effect. It's done in a lab and us also tied into the IVT and injector tip temp tables.. This is a brief overview.

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  4. #4
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    What does increasing or decreasing the # do?
    2018 Infiniti Q60s


    2004 350z/LS2: ERL 434ci, 11.8:1,TFS245cc,262/266@113+3,Fast102,NX 102 plate,60#injectors/return w/twin 255s
    Old setup: CNC'd317s, Fast 102, 228/228@114, PT88,83#injectors/full return system. 10.84@138

  5. #5
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    Well I figured it was something like that, but what does this table actually do?
    When arguing with an idiot, make sure he isn't doing the same thing....

  6. #6
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    That makes three of us - I too am curious.

  7. #7
    Senior Tuner mowton's Avatar
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    This is the best explanation I have seen.....Hope I remember it right

    Think of it as a Bucket with a hole in it. The amount of water which enters the bucket is X, the hole respresents water which will not be in the bucket even though you think you filled it. So, you need to add more water to try and maintian the right amount of water in the bucket based on the loss from the hole......the difference is what the PCM needs to calulate based on wall fuel (some will stick and not make it into the cylinder) impact and the amount of fuel that actually evaporates off the hot intake parts like the valves (evaporation).

    The larger the impact numbers, the more of the injected fuel will stick so the PCM "adds a bit more". The lower the evaporation number, the less fuel will evaporate so it has to take a bit out. It is a constant calculation/adjustment. Chris explained it best in this link..

    http://www.hptuners.com/forum/showth...Gain+Factor%22

    Ed M
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  8. #8
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    good stuff