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Thread: Spark.Correction/AFR Correction table

  1. #1

    Spark.Correction/AFR Correction table

    Is this table only used during "Cruise Mode" or can it be used to add/subtract from the Main timing table when at WOT in PE mode? AND the Main Spark Advance Max Speed setting is 4 MPH in the stock 2002 Camaro tune. I don't want my Main Spark disabled at all so can I just max that table out? What's the pros and cons of changing the Max Speed table.

  2. #2
    Concerning the Main Spark advance/ Max speed disable table being set at 4mph, I believe that is the mph the main spark table is disabled to allow the over and under speed functions to kick in. I think I may have been looking at it the wrong way previously.

  3. #3
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    Yes, you were. Below 4 mph it goes into idle mode.

    As far as the spark AFR correction table, yes, you can use it as you wish. The HPT description about lean cruise is confusing.

    Most factory calibrations have all 0's loaded. Mine was populated, and was adding timing in boost. Oops!

    Ron

  4. #4
    Advanced Tuner blownbluez06's Avatar
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    Why do you want to disable it at low speeds/idle? It's designed to stabilize your idle and is the quickest moving adaptive you have to make it happen (at least it is in the DBW vehicles). If you have surging or some anomaly that's occurring, it's possible you have the wrong values in there, but I wouldn't kill it. What I often see happen is people put values too high in tables and when one threshold is struck, it triggers an oscillation from overshooting to control it, whether it be airflow, spark or fueling. The trick is to figure out which values are overreacting and adjust accordingly. I liken it to a patient coming in with a brain tumor, complaining of headaches and the doctor handing out pain pills for it. If there's a problem, isolate and fix the problem.


    disregard this^^ thought you were trying to wipe out over/underspeed tables.
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  5. #5
    Senior Tuner eficalibrator's Avatar
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    AFR has an influence on burn rate and torque. Because of this, it's absolutely appropriate to have this table populated and active at all times.

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    In some factory calibrations it's not populated. LS1 Camaro and Corvette for example. Can you explain why?
    Since it is an adder/subtracter table, I would think the main spark tables would have to be altered when using this table?

    We all have a small fraction of your tuning/calibrating knowledge, it would help if you could elaborate further.

    Ron

  7. #7
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    Quote Originally Posted by RonSSnova View Post
    In some factory calibrations it's not populated. LS1 Camaro and Corvette for example. Can you explain why?
    Since it is an adder/subtracter table, I would think the main spark tables would have to be altered when using this table?

    We all have a small fraction of your tuning/calibrating knowledge, it would help if you could elaborate further.

    Ron
    I think you'll find it used/populated more in vehicles with delayed PE...when PE is delayed, a certain airflow will have a changing AFR, it could be stoich, it could be what's in your PE table...and depending on the enrichment rate, it could be anywhere in between.

    As a result, on those vehicles, you'll usually see lower numbers in the main spark table for airflow you hit at full throttle, and then the AFR correction table will add in the advance it can/should have when the PE AFR hits..

    On lots of LS1 Camaro/Corvette applications, PE is not delayed, so it's really not a big deal...since you can't get to that airflow range without being in PE, and the PE enrichment is not delayed, and introduced all at once, there's not really a need to have lower advance in the main table with a correction table adding anything back in.
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  8. #8
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    Thank you. That explains a lot.
    I was wondering if there were conditions between stoich and PE.
    I have two cars. C5 vette, and my turbo 5.3 nova with a 99 Camaro PCM.

    Certainly no PE delay in the Nova.

    Appreciate the insight

    Ron