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Trans tuning Questions for the trans guru

This is a discussion on Trans tuning Questions for the trans guru within the Computer & Tuning forums, part of the LSx Technical Help Section category; I am unable to get a snappy 1-2 shift at full throttle with the HPtuner trans tuning. I have the ...

  1. #1
    Moderator Firebirdjones's Avatar
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    Trans tuning Questions for the trans guru

    I am unable to get a snappy 1-2 shift at full throttle with the HPtuner trans tuning. I have the trans very snappy for everything under full throttle and I'm pretty happy.
    Right now delivered trans torque at the 1-2 full throttle shift is 278 ft lbs. On my base shift pressure I already have 85 from 260 ft lbs. on up and it hits the max of 96 at around 300 ft lbs.
    As you can see I am already near the max of 96 the graph indicates. Not sure where else to go from here.
    I have looked at the pressure multiplier table and it's currently got #1 in the areas the trans operates, which to me doesn't seem like much of anything. Anyone mess with this table? Since I am close to max pressure accoring to the base table,,,will the multiplier table override that? Or will it just hit a dead end? I need it to shift harder on the 1-2,,,,the 2-3 and 3-4 are okay. I am getting some good ideas on Hptuner but I need to post the tune to get any further, and I am working on trying to accomplish that Thanks, Larry.

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    Senior Member mrr23's Avatar
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    dark bowling green
    2000 corvette

    you might be having a problem with the 2nd gear band getting worn.

    to post the tune on hptuners, use the attachment feature, when making a post.

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    Red
    2002 T/A

    do you have a shift kit?

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    Moderator Firebirdjones's Avatar
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    No shift kit. I am pretty sure the trans is healthy. I can turn up the line pressure manually at the EPC solenoid and it bangs second gear hard. But when I turn that back to stock and try to do it with line pressure in HPtuner I can't get WOT 1-2 shift very snappy. I seem to be missing an adjustment somewhere? There has to be a reason why I can do it manually but can't do it with the computer,,,,,,I know I am a computer dummy, you don't have to point that out

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    Red
    2002 T/A

    I was having too much 1-2 SNAP after shift kit+upping pressures.
    Do you have traction control?

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    Moderator Firebirdjones's Avatar
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    Ya I have traction control,,,but I always turn that off with the switch on the dash. Does it still have some effect even when turned off?

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    Quote Originally Posted by Firebirdjones View Post
    Ya I have traction control,,,but I always turn that off with the switch on the dash. Does it still have some effect even when turned off?
    Nope. Try posting your tranny pressure tables so I can compare it to mine. I don't know how so someone else will have to help with that.

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    King 0f n00bz shady milkman's Avatar
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    blacker than wesleysnipes
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    get the shift kit. it will take care of that 1-2 wot shift..trust me

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    The other tables that determine shift "snappiness" is the "shift time " table.Stock is usually about .45 secs. at low tps and then slows up as you go to WOT to about .54. When tuning many tuners including myself lower this # to .20 on the entire 1-2 shift table. The other table that would effect a sharp shift would be the TQ management or the TQ Reduction Upshift table---as much as 30% of the TQ can be subtracted at WOT during the 1-2 shft -making it sluggish--at maximum TQ it takes out as much as 37% on some cars----STOCK-- !!!!--It is not safe to command any less than a .20 shift time but a .20 is completly safe--as far as TQ reduction or management that is a personal choice on how much protection you want to keep in for your drivetrain--A safe amount that I take out often is 1/2 or 50%--And then I've taken out all of it with no problems also --but you are gonig to have to make that call--As an example on my friends C5 with about 325 RWHP we took allof the TM out--been that way for 2 years and all is fine--On my C5 with 390 RWHP I only took out 15 % in 1st gear as the shift is very violent with any more taken out and it breaks the tires loose badly--howver in the 2-3 and 3-4 shifts I have 50% taken out and it works all fine-- My opinion of course--

  10. #10
    Moderator Firebirdjones's Avatar
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    Interesting info on that tblu92,,,,thanks for sharing. I am starting to get a handle on it now. It's working better, just looking for a little more. I played with it at the track last weekend and made a little progress,,,,

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