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Thread: What is the difference between shifting VSS and RPM?

  1. #1
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    Lightbulb What is the difference between shifting VSS and RPM?

    Guys,

    1. Why we have shifting vs VSS and vs RPM? And how does it work?

    2. Let's assume that the first gear set point for shift up is at 6000 rpm, 60 KMH. will it consider whichever comes first?


    Regards,

    Odd Boy

  2. #2
    Joe (Moderator) joecar's Avatar
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    Both conditions have to be met for the WOT shift to be commanded.

    To make it shift where you want (either MPH or RPM), you set one lower than it should be, and you fine tune the other.

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    Buddy,

    what do you mean by:

    [QUOTE=joecar;70787]Both conditions have to be met for the WOT shift to be commanded.QUOTE]
    Regards,

    Odd Boy

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    I think what he means by "Both" conditions need to be met before the shift occurs is that both conditions have to be met.

    Ex. If you want it to shift from 1 to 2 at 6000 rpm's then you have to set the speed less than whatever speed you would be at 6K. With my current gears/tires I am at 5952 rpm's at 46 MPH. If I set the MPH to anything higher than 46 then it will not shift at 6K because it has not met both conditions.

    Ex.1
    Condition 1: 55 MPH
    Condition 2: 6K RPM
    It will not shift until 55 MPH is met which will not be until 7116 rpm's.
    It met the rpm condition but has not yet reached the MPH so it will not shift until it reaches 55 MP.

    Ex.2
    Condition 1: 40 MPH
    Condition 2: 6K RPM
    It meets MPH condition at 40 but will not shift until it reaches 6K rpm when both conditions are met.


    That is how I take his explanation.

  5. #5
    Lifetime Member Ninety8C5's Avatar
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    I think what he means by "Both" conditions need to be met before the shift occurs is that both conditions have to be met.



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    So, is both condition applicable at WOT only?? or every where? I mean on normal and hot modes as well
    Last edited by odd boy; May 18th, 2008 at 04:57 PM.
    Regards,

    Odd Boy

  7. #7
    Joe (Moderator) joecar's Avatar
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    Yes, in any given mode (normal, hot, performance), both conditions have to be met in that mode...

    those conditions apply only at "WOT"...

    for the trans. "WOT" is defined by D1206 (rising TP, entering "WOT") and D1207 (falling TP, leaving "WOT").

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    I think what Odd Boy is asking is if during non WOT(normal driving) if it still needs to meet both(RPM & VSS) conditions before it will upshift. It looks like it only uses VSS(D0901, D0902, D0903) under non WOT driving since RPM is used only if in WOT.

  9. #9
    Joe (Moderator) joecar's Avatar
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    Oh, I see what he's asking...

    Yes, at part throttle (PT) the PCM uses the PT upshift/downshift tables: D0901-2 and D0906-8.

    Edit: I meant D0901-3 and D0906-8.

    Last edited by joecar; May 19th, 2008 at 07:55 AM.

  10. #10
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    Quote Originally Posted by joecar View Post
    Oh, I see what he's asking...

    Yes, at part throttle (PT) the PCM uses the PT upshift/downshift tables: D0901-2 and D0906-8.
    You mean D0901-3 and D0906-8 right, j/k.

    Joe, can you figure out this one: http://forum.efilive.com/showthread.php?t=8048

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