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Thread: m157 knock retard

  1. #1
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    m157 knock retard

    During logging, i logged all cylinders knock retard. HP tuners work like all loggers or are their still updates to be had?
    Last edited by 5soko; 11-02-2023 at 09:36 AM.

  2. #2
    Senior Tuner BackyardTurbo_FTW's Avatar
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    no, thats the amount of timing it is pulling back. Should be easy to compare your actual timing to the timing table and see you aren't getting the commanded timing amount

  3. #3
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    gotcha
    Last edited by 5soko; 11-02-2023 at 09:35 AM.

  4. #4
    Senior Tuner BackyardTurbo_FTW's Avatar
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    Its not uncommon for stock tunes to be set at a higher timing amount and then they rely on the knock sensor to adjust the timing for different qualities of gas, air, etc. BUT, OEM's will also set the decay rate to be very slow when knock correction is applied as well. This way if it senses any knock it will pull timing and hold that amount of retard for an extended period of time to try and keep the car safe. Also, they typically pull more than required and you are likely having timing pulled in areas it doesnt need it because of that slow decay rate.

    This is why custom tuning yields great results, you are fine tuning the car for your fuel quality, air quality, elevation, parts upgrades etc etc etc.

  5. #5
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    Quote Originally Posted by BackyardTurbo_FTW View Post
    Its not uncommon for stock tunes to be set at a higher timing amount and then they rely on the knock sensor to adjust the timing for different qualities of gas, air, etc. BUT, OEM's will also set the decay rate to be very slow when knock correction is applied as well. This way if it senses any knock it will pull timing and hold that amount of retard for an extended period of time to try and keep the car safe. Also, they typically pull more than required and you are likely having timing pulled in areas it doesnt need it because of that slow decay rate.

    This is why custom tuning yields great results, you are fine tuning the car for your fuel quality, air quality, elevation, parts upgrades etc etc etc.
    Excellent
    Last edited by 5soko; 11-02-2023 at 09:36 AM.

  6. #6
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    That just looks like too much boost for the fuel quality you're running. Timing is very low as a result. A bit less boost with more efficient ignition and lower IATs would yield a faster car IMO.

  7. #7
    I was just curious you said you have a rentech tune and I was wondering why you switching to HP ? From what I read renntech supposed to be the best for Mercedes so I'm very interested to hear if you don't mind.