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Thread: Changing stoich

  1. #1
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    Changing stoich

    Changing stoich on the EcoBoost, does it always read on the gas scale, or does it change to the true scale for your fuel?

    For example, WOT AFR with a stoich setting of 14.7 reads 11.5 on the gas scale.

    WOT AFR with a stoich of 11.3 reads 11.5 on the "11.3" scale...and not the gas scale. Is this true?

  2. #2
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    Does the AFR follow the stoich value in the EcoBoost platform?

  3. #3
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    I believe you're really asking if it goes off of lambda values and does the stoich value in afr change with different fuels? Stoich is always lambda of 1 but the afr is different based on fuel used for that same lambda of 1.
    Last edited by trdtoy; 08-26-2020 at 12:07 PM.

  4. #4
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    Quote Originally Posted by trdtoy View Post
    I believe you're really asking if it goes off of lambda values and does the stoich value in afr change with different fuels? Stoich is always lambda of 1 but the afr is different based on fuel used for that same lambda of 1.
    Yes, I think so.

    So, basically, if my stoich is set to 9.85, will my WOT AFR (not lambda, because we all know that will be the same for all fuels) display 6.95 AFR on the WB PID? Or will it display 12.5 AFR which is the reading for the gas scale (14.7)?

  5. #5
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    Your afr will be what the tune makes it be but what you datalog will depend on what you're logging with and if it logs true afr or lambda with and afr conversion depending on the fuel used.

  6. #6
    Advanced Tuner LastPlace's Avatar
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    STOP thinking about AFR, Stop worrying about AFR.

    AFR doesn't mean anything to your ECU.

    You Tell the ECU what AFR lambda 1.0 is and it doesn't care after that (only as a reality check)

    Everything it does power enrichment wise is a % richer then lambda 1.0 of what ever is in your tank.
    Last edited by LastPlace; 09-03-2020 at 06:53 PM.