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Thread: 4l60e - 96 Corvette performance tuning

  1. #1
    Carb and Points!
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    4l60e - 96 Corvette performance tuning

    Hi, I just purchased a used 14005 and am waiting for a proper serial cable to arrive to begin programming. I plan to do it from a desktop running WinXP since Ive read all the horror stories and dont want to go there. (it came with a usb to serial converter).

    My question is does anyone have an recommendations on how to setup a performance tune for the 4l60e?

    Some of my "wants" are:

    Keep it out of 4th until I hit 60mph

    More aggressive downshifts (much sooner than stock)

    Id like to mess around with locking the torque converter sooner, especially on downshifts

    also, is there a way on the 96 vette I could wire in the infamous performance mode switch?


    thanks.. Im new to this forum and have spent over an hour reading.. good stuff on here!

    EDIT: I should have placed this in the tunercat section.. if a moderator could move it Id appreciate it.
    Last edited by barchetta; 1 Week Ago at 02:57 AM.

  2. #2
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    Mostly you're changing the shift tables.

    Keeping it out of 4th longer below 60mph is just putting no values <60 into the shift curve for the 3-4 shift.

    By more aggressive downshifts, I believe you mean they happen with less throttle compared to a stock setup. To get that, just put the downshift curves tighter under the upshift curves. Match the top of the shift curves and the kickdown table values so odd things don't happen going in and out of kickdown.

    Personally, I use a s-curve for the shift curves. Starting at the minimum shift speed, I start ramping up quickly at around 30% throttle and so the curve goes flat for the last 20-30% throttle. Google Image s-curve if you're not sure what I mean by that type of curve. For all-out performance, drive at 10%, 20%, 30% and 40% throttle in each gear and note the steady state speed achieved. Then, make a curve that shifts a little below that speed following the S shape up to the red-line shift speed. Realistically, this will only likely work for the 1-2 and 2-3 shifts but it gets you a general idea. Then, work from there and adjust as you like.

    The torque converter is a couple of tables. First try adjusting them to get it how you want similar to doing the shift curves.

    If a 96 LT1 car could be had with the performance switch then you can add it. Try to find a wiring diagram for a 96 that shows it.

  3. #3
    Carb and Points!
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    Quote Originally Posted by lionelhutz View Post
    Mostly you're changing the shift tables.

    Keeping it out of 4th longer below 60mph is just putting no values <60 into the shift curve for the 3-4 shift.........................

    Incredibly helpful thank you.


    What I meant by more aggressive on the downshifts is.. if Im in 4th and I brake, as the speed goes down I can feel the car quickly downshifting.. so if Im doing 75 and I brake, as my speed hits say 55-60 I can feel it drop to third and the TC kicks in and revs go up consequently.. and perhaps I hit 40, and it drops to 2nd with same characteristics.. I used to road race and I kinda want that sort of transmission response as best as possible. Im handicapped in my right arm so an automatic was a must for me in case you are wondering.

    This is where that performance switch would enter as if Im just out cruising I may not want this.. I guess it was in firebirds same year.. or something like that but in the vette its just always "on". I think I saw the performance settings in the tables.. I will look into it more and as you suggest maybe wire a switch.. I remember its pin 21 or maybe 51 on one of the connectors.. grounded on, not grounded off or visa versa.

    Anyway.. thanks this is a great starting point for me.

  4. #4
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    Yes, you might not like it downshifting like that when normally driving. If you have it automatically downshift to 2nd at 40mph then you really can't have it automatically upshift to 3rd until above 40mph. So, you could find you're driving around with the revs too high.

    You'll also probably find the 4L60e doesn't give a very good feel when forcing downshifts. There is no rev-matching so it would just kind of jerk into the lower gear.

    You don't need the TCC locked up to get engine braking either.

    The performance switch is a momentary pushbutton that grounds a pin. There should also be a PCM output that could be used to light an indicator.

  5. #5
    Carb and Points!
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    Quote Originally Posted by lionelhutz View Post
    Yes, you might not like it downshifting like that when normally driving. If you have it automatically downshift to 2nd at 40mph then you really can't have it automatically upshift to 3rd until above 40mph. So, you could find you're driving around with the revs too high.

    You'll also probably find the 4L60e doesn't give a very good feel when forcing downshifts. There is no rev-matching so it would just kind of jerk into the lower gear.

    You don't need the TCC locked up to get engine braking either.

    The performance switch is a momentary pushbutton that grounds a pin. There should also be a PCM output that could be used to light an indicator.

    I feared everything you just said :).. Oh well, at least I can mess around a little and have fun with it. My daily driver is a 8 speed auto BMW.. amazing.. this is old technology so it is what it is.

  6. #6
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    You need a newer PCM setup running a 6L80e or better with paddle shift. Then, you can downshift and get rev matching.

  7. #7
    Carb and Points!
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    Need; no, want; yes :). It is what it is.. just a weekend toy.. just removing all the GM fuel saving logic will increase performance.

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