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  1. #1
    ptscon's Avatar
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    4-Teck cylinder knock gain

    Do 4tecs need a different knock gain per cylinder or are they all the same.


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    It got WIFI and touchscreen ! PWCGUY's Avatar
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    Quote Originally Posted by ptscon View Post
    Do 4tecs need a different knock gain per cylinder or are they all the same.
    No need for different gain. What ECU are you using to measure knock ?

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    ptscon's Avatar
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    Quote Originally Posted by PWCGUY View Post
    No need for different gain. What ECU are you using to measure knock ?
    Vipec, for some reason they have different cylinder gains on the different stage maps. Unless the knock sensor location changes shouldn't gain be the same on all 4tecs, especially if internals aren't changing?

    I thought I was done discovering weird stuff in the riva base maps.


    OEM: 0.65 / 1.50 / 1.50
    Stage 1: 1.00 / 0.80 / 1.00
    Stage 2: 1.00 / 0.80 / 1.00
    Stage 3: 0.80 / 0.80 / 1.00
    Stage 4: 0.80 / 0.80 / 1.00


    1.00 / 0.80 / 1.00 would make most sense to me since cyl2 is closest to the knock sensor.

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    It got WIFI and touchscreen ! PWCGUY's Avatar
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    if you want to get fancy the sensor is closest to cylinder 2. I would go with the 1.00 / 0.8 / 1.00. Typically you would not be knocking only with bad fuel. Final ignition timing should not be close to knock as you will have heat issues before getting any knock. What ignition timing are you at on top and is the motor a 260 or 300 ?

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    ptscon's Avatar
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    Looks like Metec basemap uses 95 / 70 / 100 ...might try that, definitely seeing most noise from #2 so maybe it's a little too sensitive at 80%

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    It got WIFI and touchscreen ! PWCGUY's Avatar
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    I did a lot of testing with Motec SKM working with Pete and Nils to make sure an actual knock event was being filtered properly. Its not straight forward. My guess is that your are not seeing actual knock events but normal engine noise that is why I was asking for your ignition timing on top end. What limits a 4Tec in terms of output is not knock limits but instead heat when running pump gas. You will melt pistons from too much heat far before knock/detonation damage on pump gas.

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    ptscon's Avatar
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    Quote Originally Posted by PWCGUY View Post
    I did a lot of testing with Motec SKM working with Pete and Nils to make sure an actual knock event was being filtered properly. Its not straight forward. My guess is that your are not seeing actual knock events but normal engine noise that is why I was asking for your ignition timing on top end. What limits a 4Tec in terms of output is not knock limits but instead heat when running pump gas. You will melt pistons from too much heat far before knock/detonation damage on pump gas.
    I'm pretty sure I'm not seeing knock, I've been only running 29 at ~16.5psi up top this season. Haven't had time to play with timing at all.

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    It got WIFI and touchscreen ! PWCGUY's Avatar
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    If that is with a 300 engine then its conservative but safe for pump gas. If you have a 260 engine then 29 deg BTDC is too conservative. 36deg final is more typical for 260 with pump gas.

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    Quote Originally Posted by PWCGUY View Post
    If that is with a 300 engine then its conservative but safe for pump gas. If you have a 260 engine then 29 deg BTDC is too conservative. 36deg final is more typical for 260 with pump gas.

    I won't have time to fine tune timing this season, I'll probably bump it up couple degrees but I doubt I'll ever run above 32-33 since I tune for 91 octane. Next season I'll setup dual ignition maps with my vipec via swich so I can jump between higher octane fuel whenever I use it.

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    Bob 1tommygunner1927's Avatar
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    Quote Originally Posted by ptscon View Post
    Looks like Metec basemap uses 95 / 70 / 100 ...might try that, definitely seeing most noise from #2 so maybe it's a little too sensitive at 80%
    Have mind set at 85/75/95.....you might be picking up noise from the S/Cer/flywheel gears.

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