shifting hard, real hard
03-30-2005, 01:31 AM
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shifting hard, real hard I don't know if this should be here or in another forum, but here it goes. I had my tranny completely rebuilt after a converter failure that caused catastophic tranny failure, just about every hard part and obviously all the soft parts. With the rebuild I had a custom 3000 stall, 2.5 str converter built. My problem is that on the 1-2 shift at the track on drag radials, the car squats so hard in the rear that the rear end hits the jounce bumpers! That can't be good. Right now my shift settings are at 90 across the board. Should I back it off a little or install air bags in the coils? Other than that the car ran real good at 12.53 w/ 1.81 short times. Oh yeah, I have BMR 1" lowering springs w/ bolt-on relocation brackets installed. Any help would be appreciated.
03-30-2005, 08:31 AM
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That's some serious squat. Are you using the lowest hole
in the relos?
I took out some shift pressure because my car would just
break loose on the 1-2 with street tires (I don't really want
drag radials). Your 2.5 STR is even higher than mine and my
engine should have well less output than yours. I think you're
hitting into some hard torque multiplication.
You could perhaps use TM to some advantage here. Not the
as-delivered, dumb-*** TM but adjusting the Max KR vs RPM
value to a point that softens the power output during shift
to something that doesn't quite make the rear end come
loose.
You might consider doing something like I did, putting air
shocks in the back with separate Schraders. That would let
you jack the back, to get better bite (possibly even rise
instead of squat) for the strip and then de-mulletize it for
the ride home. Independent Schraders would let you bias
weight to the right tire which helps on the low-torque-bias
stock Torsen.
in the relos?
I took out some shift pressure because my car would just
break loose on the 1-2 with street tires (I don't really want
drag radials). Your 2.5 STR is even higher than mine and my
engine should have well less output than yours. I think you're
hitting into some hard torque multiplication.
You could perhaps use TM to some advantage here. Not the
as-delivered, dumb-*** TM but adjusting the Max KR vs RPM
value to a point that softens the power output during shift
to something that doesn't quite make the rear end come
loose.
You might consider doing something like I did, putting air
shocks in the back with separate Schraders. That would let
you jack the back, to get better bite (possibly even rise
instead of squat) for the strip and then de-mulletize it for
the ride home. Independent Schraders would let you bias
weight to the right tire which helps on the low-torque-bias
stock Torsen.
03-31-2005, 12:17 AM
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Thanks for the insight! I'm in the top holes of the relocation brackets right now, I'll try the lower ones if you think it will help. I thought of using two airbags w/ dual schraders, I don't want to switch to air shocks b/c I just installed about $390 worth of Bilsteins. Torque management hmmmm, that's an interesting thought. I actually did think of that as a possibility, but wrote it off as my being crazy! Lol! I guess I'll try the bracket adjustment first and work from there.