Explain Torque Management
05-20-2004, 03:25 PM
#2
TECH Senior Member
The one thing it does that bothers me most is pulling the timing advance way back on the shifts. It's bad enough with an auto tranny car but sometimes with an M6 it'll make the car completely fall on it's face if you powershift it just right. 
I believe it's meant to extend the life of the drivetrain.
I believe it's meant to extend the life of the drivetrain.
05-20-2004, 08:22 PM
#4
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The PCM calculates delivered torque from the engine,
and to the transmission. On the tranny input side it
tries to figure in the converter torque multiplication.
Transmission protection is one reason for torque
management. Beats spending money on heavy duty
parts when you can avoid warranty claims in software.
There are tables in the PCM that set the amount by
which to reduce engine torque value during shifts.
For the duration of the shift cycle, if you are at 400
lb-ft input shaft torque the PCM will try and reduce
this by 30% (for example, from my stock F-body .bin).
It has other mysterious internal tables that tell it how
much spark to pull, for how much torque reduction.
The accuracy of these tables is suspect, to me, because
in fact it pulls -all- timing, to -10 degrees, for the whole
shift.
So the power cuts out, the car coasts through the shift
and picks back up.
The shift time is also programmed over-long, giving you
more time to appreciate the fine job the programmers at
GM have done on your behalf.
If you want a nicer shifting A4, try having the TM tables
do an increasing reduction in torque, starting later, such
that a maximum torque of higher value is enforced. Like
(pull this into Excel and it will look better)
Shift Torque Reduction
Torque 0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640
Max=300 0 0 0 0 0 0 0 0 6 17 25 32 38 42 46 50 53
Max=450 0 0 0 0 0 0 0 0 0 0 0 0 6 13 20 25 30
At the 450 row settings I only have TM at higher-
throttle shifts (where it is, like, worthwhile in the
protection sense). Though the 3-4 from factory is
not torque managed at all, so you might ask the
question, is it really necessary (or, "why do I keep
burning up 3-4 clutch packs?").
Then reduce all of your shift adaptation time table
entries to something like 0.100 - 0.200 (you could
zero, and get full torque-defined line on shifts, as well
but somewhere in here would just firm it up, some).
and to the transmission. On the tranny input side it
tries to figure in the converter torque multiplication.
Transmission protection is one reason for torque
management. Beats spending money on heavy duty
parts when you can avoid warranty claims in software.
There are tables in the PCM that set the amount by
which to reduce engine torque value during shifts.
For the duration of the shift cycle, if you are at 400
lb-ft input shaft torque the PCM will try and reduce
this by 30% (for example, from my stock F-body .bin).
It has other mysterious internal tables that tell it how
much spark to pull, for how much torque reduction.
The accuracy of these tables is suspect, to me, because
in fact it pulls -all- timing, to -10 degrees, for the whole
shift.
So the power cuts out, the car coasts through the shift
and picks back up.
The shift time is also programmed over-long, giving you
more time to appreciate the fine job the programmers at
GM have done on your behalf.
If you want a nicer shifting A4, try having the TM tables
do an increasing reduction in torque, starting later, such
that a maximum torque of higher value is enforced. Like
(pull this into Excel and it will look better)
Shift Torque Reduction
Torque 0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640
Max=300 0 0 0 0 0 0 0 0 6 17 25 32 38 42 46 50 53
Max=450 0 0 0 0 0 0 0 0 0 0 0 0 6 13 20 25 30
At the 450 row settings I only have TM at higher-
throttle shifts (where it is, like, worthwhile in the
protection sense). Though the 3-4 from factory is
not torque managed at all, so you might ask the
question, is it really necessary (or, "why do I keep
burning up 3-4 clutch packs?").
Then reduce all of your shift adaptation time table
entries to something like 0.100 - 0.200 (you could
zero, and get full torque-defined line on shifts, as well
but somewhere in here would just firm it up, some).