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Thread: Knock Learn Factor on E39

  1. #1
    Advanced Tuner
    Join Date
    Dec 2014
    Posts
    592

    Knock Learn Factor on E39

    I'm trying to get a better understanding of how Knock Learn factor works on the E39. I understand that it starts at "0" (100% High Octane Table) and moves towards "1" (Low Octane Table) as it experiences knock - based on your knock learn settings.

    However, what I don't understand is if it's a "global" thing or if it's a "per combination" type thing. For example, if I get knock at 2000 RPMs/0.44g/cyl and the Knock Learn value increases, does that knock learn value affect ALL RPM/Airmass combinations or just the 2000/0.44 combination?

    From what I've seen in my scan logs, it almost looks like it's "per combination" becuase I will be reviwing my log and the Knock Learn value will go from 0.0 to 0.3 even though no knock has occured, so it seems to remember the RPM/airmass combination and keeps differernt values per combination... Is that correct?

    Thank you!

  2. #2
    Advanced Tuner
    Join Date
    Dec 2014
    Posts
    592
    The reason that this is important to me is becuase if it the Knock Learn values are "per combination", then I'm not going to waste time trying to elimate knock by reducing timing - I might as well just let the Knock Learn do it's think and elimnate knock on it's own based on where it sees knock.

    If, on the other hand, knock experienced for a certain "combination" would cause the timing to be reduced "globally" for all RPM/airmass combinations, then I'd want to work on the timing tables to avoid knock that way and use Knock Learn as a last resort "safety net".

    Anyone? I havne't been able to find this answer via searches... Just general information about Knock Learn - nothing detailed...

    Thank you!