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Thread: Just putting this out there...

  1. #1
    Tuner in Training japslpr's Avatar
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    Cool Just putting this out there...

    Has anyone tried messing with the transmission tables to allow the car to shift more like a road racing car??

    In a GTP bin you have normal shift mode setting and performance shift mode settings. (you also have cruise, and hot, but I don't know when they are used). CAn you modify the downshifting tables so that your car is always in or close to its powerband, by making your car shift into 2nd at 65-70mph and into first around 30mph in perf. shift mode?? How would you modify the tps settings in those tables to allow the car also to engine brake by shifting into the lower gears sooner?

    Just a thought...
    Jae
    1999 GTP
    XPZ, 1.6 RR's, 2.8-2.6 DUB, Stg 4 Gen III M90, P&P LIM, N*, LQ4, FWI, Stg 3 Heads, ZZP Stg 3 IC , 42.5lb, SLP Headers, 2.5"SLP Catback, Cutsom Tranny, 3.29's, 3500stall, ICCU, LS1M, GMPP Susp, BMR F/R Sways, Next LVL STB, F-boby Brakes

  2. #2
    Advanced Tuner
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    Doing this would not be a problem from a VCM file or PCM standpoint, but I don't think the trans would take it for very long. Even with hardened parts I think you would drastically reduce your trans life to the point I would be afraid of trying it.

    The transmissions are the weak link in the system as it is. This is the reason I am not a fan of major trans torque reduction reductions (that sounds funny!). GM states that the 4T65-E HD transmission is good up to 285 ft/lbs of torque. Well, these cars come from the factory with 285 ft/lbs of torque.
    -Eddie

    1998 GTP - 3.4 [3.2] [3.0] MPS - custom CAI - F.1 Ram Air hood - XP Cam - Ported Heads - 1.84/1.60 Si valves - 1.6 HS Roller Rockers - 72mm Ported TB - LQ4 MAF - 42.5# Lucas Injectors - Pacesetters
    1/4 PB - 13.025 @ 106.81 MPH w/ 2.069 60'

  3. #3
    yea agreed, down shifting the trans manually or via computer, will destroy it very quickly. However it is possible, adjusting the down shift speeds.

  4. #4
    Tuner in Training japslpr's Avatar
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    I agree that it wouldn't last long, but for every once in a while I think it would be fun. Maintence would have to be a regular thing at shorter intervals. I would lower the line pressures for upshifting and downshifting for sure. I'd just like to have a file that I could try this out with.
    Jae
    1999 GTP
    XPZ, 1.6 RR's, 2.8-2.6 DUB, Stg 4 Gen III M90, P&P LIM, N*, LQ4, FWI, Stg 3 Heads, ZZP Stg 3 IC , 42.5lb, SLP Headers, 2.5"SLP Catback, Cutsom Tranny, 3.29's, 3500stall, ICCU, LS1M, GMPP Susp, BMR F/R Sways, Next LVL STB, F-boby Brakes

  5. #5
    lol, just don't do it man. Its just one of those things, even zzp won't warranty any trans that got put into 2nd 3rd and let the drag of the engine slow the car, which would be basically the same thing. There is a little bearing that will shear itself to death and let little shavings go around the trans and kill everything. I know its interesting to try, but just leave that one alone and let the trans do what it does best and accelerate the car. Maybe you can get away with doing it for a while, or you might be that guy that does it one time and toasts the tranny right away. Do you really want to get a new trans just to try something out? I sure wouldn't especially since they cost an arm and a leg to get, and even if they are built tranny's, that will still kill them.

  6. #6
    Tuner in Training japslpr's Avatar
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    Quote Originally Posted by e85grandprix
    lol, just don't do it man. Its just one of those things, even zzp won't warranty any trans that got put into 2nd 3rd and let the drag of the engine slow the car, which would be basically the same thing. There is a little bearing that will shear itself to death and let little shavings go around the trans and kill everything. I know its interesting to try, but just leave that one alone and let the trans do what it does best and accelerate the car. Maybe you can get away with doing it for a while, or you might be that guy that does it one time and toasts the tranny right away. Do you really want to get a new trans just to try something out? I sure wouldn't especially since they cost an arm and a leg to get, and even if they are built tranny's, that will still kill them.

    LOL...
    Yeah, it will probably destroy the tranny, but that is what the spare is for in my garage! I built my own tranny. Cheaper that way and It's not to difficult. Of course you have to worry about time, but I can get it out by pulling the engine with it in around 4 hours.

    Anyway, I was just wondering if anyone ever gave this any thought? I came up with the idea watching an AUDI R8 go around Motegi Ring on Streetfire and it was an automatic.
    Jae
    1999 GTP
    XPZ, 1.6 RR's, 2.8-2.6 DUB, Stg 4 Gen III M90, P&P LIM, N*, LQ4, FWI, Stg 3 Heads, ZZP Stg 3 IC , 42.5lb, SLP Headers, 2.5"SLP Catback, Cutsom Tranny, 3.29's, 3500stall, ICCU, LS1M, GMPP Susp, BMR F/R Sways, Next LVL STB, F-boby Brakes

  7. #7
    Quote Originally Posted by japslpr
    LOL...
    Yeah, it will probably destroy the tranny, but that is what the spare is for in my garage! I built my own tranny. Cheaper that way and It's not to difficult. Of course you have to worry about time, but I can get it out by pulling the engine with it in around 4 hours.

    Anyway, I was just wondering if anyone ever gave this any thought? I came up with the idea watching an AUDI R8 go around Motegi Ring on Streetfire and it was an automatic.
    WAIT WAIT WAIT!!!!!!!! You do your own what and pull out the what in how long?!?! U have an extra trans?! Hook a brotha up, i'll drive out there buy it and you install it!!!! lol, seriously, wanna work somethin out? lol

  8. #8
    Tuner in Training japslpr's Avatar
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    Quote Originally Posted by e85grandprix
    WAIT WAIT WAIT!!!!!!!! You do your own what and pull out the what in how long?!?! U have an extra trans?! Hook a brotha up, i'll drive out there buy it and you install it!!!! lol, seriously, wanna work somethin out? lol
    What are you looking for a stock rebuilt tranny or do you want upgrades like 7/8" single chain gear conversions, extra clutches, upgraded z-pack, hardened 4th, new seals, TC, shift kit, etc...

    We could possibly work something out.
    Jae
    1999 GTP
    XPZ, 1.6 RR's, 2.8-2.6 DUB, Stg 4 Gen III M90, P&P LIM, N*, LQ4, FWI, Stg 3 Heads, ZZP Stg 3 IC , 42.5lb, SLP Headers, 2.5"SLP Catback, Cutsom Tranny, 3.29's, 3500stall, ICCU, LS1M, GMPP Susp, BMR F/R Sways, Next LVL STB, F-boby Brakes

  9. #9
    Potential Tuner
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    japslpr, I think I've seen you on the GPF.net forums. I live in MoCo, Maryland and I would def be interested in a trans build and install. I already can aquire a core from someone. You have the setup I'm looking to do. XPZ cam + support. I want to get my trans built first before I move to anything else. Thanks

  10. #10
    Tuner ZeroBoostBuick's Avatar
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    Since my Regal is not boosted, it doesn't have all that torque so I got my 2-1 downshift at 42mph (awesome for passing slow people) and I sure as hell am not going back to 35mph stock setting (I'll consider a few mph lower if/when I kill the tranny).

    Last spring I dropped the tranny pan 3 times in 3,000 miles, changed the filter every time with GM filter, first pan drop I used dex6 and the next 2 pan drops I used AMSOIL... keeping my fingers crossed.

    If you can afford it, you will not regret using Amsoil ATF.

  11. #11
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    Buick, its been several months, how has your trans been?

  12. #12
    I've re-programmed my "non-performance mode" shift behavior rather drastically.

    It has basically been re-configured to disallow the transmission from shifting out of first gear until shift speed has been reached regardless of throttle position.

    Because the car makes so much power, it will basically light the tires at any speeds involving 1st gear. In order to launch on slippery surfaces, you need to go down pretty slow with the gas, sometimes so slow that the trans upshifts.

    With it programmed to not shift until speed is reached, it allows you to be more gentle on the gas while still holding it in first.

    -----

    Furthermore I changed downshift tables for that mode as well. Basically to limit WOT to 2nd gear. (above 9mph)

    This was again aimed at wheel spin... If you were driving say 27mph... and were to floor it, it would normally dump to first and light the tires up... a quick depression of the shift button, and it goes to 2 instead of 1, allowing you to get on it (and pass someone) without making a scene <grin>

    -----

    On a hot summer day, 1st might be desired, in which case, you can leave it in performance mode.