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Thread: 4t65e-hd shifting questions

  1. #1

    4t65e-hd shifting questions

    I've done some data logging and I see that I could raise my 1-2 shift and 2-3 shift a bit to get it farther in the powerband since I have a XP cam. Right now my 1-2 shift is set at 44mph and like 5100rpm...it shifts at around 6200. I'd like to see it shift closer to 6300 or 6400 rpm and wondering if I raise the mph to 45mph it will get it a bit closer? I'm thinking both have to be met in order to shift and since the mph is better to just add one rather than guess on rpm since I got it about right now. Will it shift based on mph and be alright? Same goes for the 2-3 shift as well.

    Let me know!
    Thanks guys.

  2. #2
    Senior Tuner
    Join Date
    Feb 2006
    Location
    Canada
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    1,957
    You have it right, raise MPH by one or two and you should get the shift point you want. From your scan I would also set your RPM to the point you are seeing the car shift at, but that's me...
    2000 Trans Am WS6

  3. #3
    Potential Tuner
    Join Date
    Jun 2013
    Posts
    6
    Just curious.. How are you logging your shift speed/rpm? I'd like to set mine up to do this also.

  4. #4
    Tuner
    Join Date
    May 2007
    Location
    Upstate NY
    Posts
    132
    For five years now i've just had my shift speed tabled zero'd out and shift only on RPM. This is easier to fine tune and the car doesn't care if it has the 18s on or the 26" slicks.

    I burned the clutches out of one of my many trans as it banged off the limiter trying to reach the required speed several times. Now it just sees the RPM and shifts, also note, as you modify the care it will have a tendency to over shoot the RPM as the trans just can't shift fast enough. You'll have to artificially lower it for it to shift where you want.
    98 Buick GSX IS3 Heads/GenVblower/cammed/intercooled and stalled
    02 Collector Edition Trans Am WS6
    94 S-10 with Rancho 3" lift on 33's
    93 Typhoon
    07 Tahoe

  5. #5
    Senior Tuner
    Join Date
    Feb 2006
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    Canada
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    1,957
    You can do it that way for sure, but if you lower your MPH by 3MPH below the MPH seen at the RPM you want , she'll shift on the mark... I also see how that method would work if you are tossing different size tires on for the track and not have to tune every time you go! Good idea there
    2000 Trans Am WS6