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  1. #1
    Moderator KANE's Avatar
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    Default Changing WOT Shift Points

    Posting some of my thoughts and experiences with changing the WOT shift points. My set up makes maximum power at 5.3/5.4k rpm. To make full usage of the band, I need a WOT shift at about 5.4/5.5k rpm when warm.

    Baseline:
    The 82's 700R4 would shift hot at 5k rpm, warmed up at 5.2k and cool at 5.6k out of first gear. The transmission has been rebuilt at some point in the past and has less than 70k miles on it. FWIW- I have a 325hp/375tq motor and a 2.87 rear gear.





    Enter the B&M governor reprogramming kit... six weights and six springs.


    OEM Weights and Springs:
    My 82's factory governor has two "e" inner weights. One has an a capital E (12.055 grams) the other has a backwards capital E (12.1540 grams). The heavy side had a factory purple (heavy weight spring) and the light side had the factory white spring (light weight).


    Handful of Results:
    Factory E weight (12.050g), Blue B&M spring
    #3 B&M weight (11.155g), Yellow spring
    ~~~~~~5.8k+ (let off to protect the engine) 1-2
    ~~~~~~5.6k 2-3

    Factory E weight (12.050g), Blue B&M spring
    #2 B&M weight (13.080g), Yellow spring
    ~~~~~~5.8k+ (let off to protect the engine) 1-2
    ~~~~~~5.3k 2-3

    Factory E weight (12.050g), Blue B&M spring
    #2 B&M weight (13.080g), green spring
    ~~~~~~5.7k warm; 5.6/5.5k hot 1-2
    ~~~~~~5.k 2-3






    Next up-
    I am going to test a few more combinations and post them.

    I have this combo in to test as of now... I would like to see the 1 gram reduction increase my rpm at WOT by about 500rpm. 2 grams made a big difference in testing the B&M weights (weights 2 and 3), looking to see if a 1 gram reduction gets me where I want to be.

    IN CAR
    Factory E weight (12.050g), Factory White spring
    #3 B&M weight (11.155g), Factory Purple


    Seems to me the GM purple is stiffer than the B&M purple... so going from GM purple to B&M blue feels like two steps down. This might come in hand later.



    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  2. #2
    Moderator KANE's Avatar
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    Default

    Results from the latest round of springs & weight combos...


    Factory E weight (12.050g), Factory White spring
    #3 B&M weight (11.155g), Factory Purple spring
    ~~~~~~5k 1-2
    ~~~~~~4.5k 2-3

    That combo created a WOT shift that was virtually the same as the factory combo. I am guessing the 1 ounce difference wasn't as big a player as the white spring was. To test that theory, I replaced the factory purple with the B&M purple and left the GM white spring in.


    Factory E weight (12.050g), Purple B&M spring
    Factory E weight (12.150g), Factory white spring
    ~~~~~~5.9k+ (let off to protect the engine) 1-2
    ~~~~~~5.5k 2-3


    So... for my car... the GM white spring seems to play a much bigger role than weights do.


    Factory E weight (12.050g), Purple B&M spring
    Factory E weight (12.150g), B&M green
    ~~~~~~5k 1-2
    ~~~~~~5k 2-3

    That was also about equal to the OEM shift points- and with a lighter purple spring. Still too low though...


    Last try...


    Factory E weight (12.050g), Purple B&M spring
    Factory E weight (12.150g), B&M yellow
    ~~~~~~5.4k 1-2
    ~~~~~~5k 2-3

    GOT IT!!!


    Knowing that running a light/heavy spring combo seems to spread the shifts over a greater range than if the springs were equal, I may try two blue springs to see if I can get a 5.4k 1-2 and 2-3, but I'm not sure that it really matters. I don't drag race this car and don't intend to. The intent was to get a shift from 1-2 that was right after I developed max horsepower, and I think I have it now.


    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  3. #3
    Moderator KANE's Avatar
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    Default

    Last August I upgraded to a 3.73 rear end.



    And promplty had to adjust the governor again .

    Never a dull moment, right?


    So I ended up using a blue and a green spring to get the shift points back to 5,300ish on WOT back in August.


    Well, I recently replaced the transmission- and upgraded to a 2k rpm stall converter. Yup... had to adjust springs again.


    This time around, I am using a blue and a yellow spring. Now... the transmission is not fully broken in yet so I have not really gotten on it to make sure I am hitting the 5,300ish mark just yet. I went to WOT once on the previous set of spring and it was around 4,500. Under 90% throttle I am at about 5k.

    I may need to go one more spring lighter to orange. We'll see...

    Thought I would share my experience as some folks might be replacing rears, gears, and trannys.
    1982 Dark Blue Corvette
    Crossfire Injection | .496"/.495" Cam | AFR Eliminator Heads | EBL | 3.73
    0-60mph in four and a half seconds



    1995 Trans Am
    1 of 1 Trans Am | 100% documented | RPOs 48U, MN6, and GU6
    1982 Chevrolet Corvette , 350 2k RPM Stall Converter + Updgraded Transmission + Governor Set For 5,450rpm Shifts 3.73 Code 42 Dark Mettalic Blue with a twist

  4. #4
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    Default

    Kane: This is one of the best articles I've read on setting shift points.

    Ideal Shift Points - Calculated for Various Configurations - LS1GTO.com Forums

    Enjoy!


    Whoosh, and blur

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