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short and long term fuel rims with boost?

Discussion in 'Engine/Tuning' started by Djstorm100, Feb 10, 2013.

  1. Djstorm100

    Djstorm100 New Member Established Member

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    Given that I have Roush S/c installed and tuned what should my Short/Long fuel trims look like? On my Aeroforce guage they kept boucing around getting a high as 8 on short and 24. Car runs great/strong and made 640 but we detuned it down to 616. Just curious about it, that's all.

    Also notice about a half tea spon in my catch can. Normal? Thinking about getting gt500 PVC Valve.
     
  2. SILV03MustangGT

    SILV03MustangGT Han Brolo CDR 5.Broliance Established Member

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    I wouldnt watch the short term/long terms on the aeroforce. Just watch the B1S1 equivalency ratio (lambda) and you'll have the info off of the widebands. if i want to know what my ST/LTs are I hook up the laptop and log through livelink.
     
  3. Djstorm100

    Djstorm100 New Member Established Member

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    whats the difference from log on the livelink and aeroforce? they are both getting info from the computer.

    what does e ratio be at?
     
  4. SILV03MustangGT

    SILV03MustangGT Han Brolo CDR 5.Broliance Established Member

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    The Aeroforce sounds like its reading them differently. STs and LTs are shown as 1.0 or .94 whatever the car is reading for example. If the E ratio is reading 1.0ish at idle then that means your seeing stoich for whatever fuel you may be using IE for E10 you would be seeing 14.1 AFR.
     
  5. 01bluesnake

    01bluesnake Authorized Vendor Authorized Vendor Established Member

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    I believe you are thinking of Lambda and what the air fuel ratio sensors are seeing. Fuel trims is a percentage correction from the base fuel table and is not measured in Lambda. If the cars short trim is 1.06 then the system is doing an immediate correction of 6% fuel to correct from the long term trim table. If the long term trim is reading 1.06% then it has learned a correction of 6% fuel added and thats what will be used in that area of the table

    Once long term fuel trim is learned, you can see numbers + or - of 1.0, and the difference is the percentage of fuel being removed or added tp the overall table. Short trim's will always be changing depending, but shouldn't be very far off of 1.0 or the MAF transfer curve or others things might not be dialed in right.

    Reading the Air fuel ratio sensors, is not the same as fuel trims
     
    Last edited: Feb 10, 2013

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