Torque Management
TECH Enthusiast
Joined: Jul 2006
Posts: 638
Likes: 0
From: San Diego
Originally Posted by 2xLS1
Torque management is a function of the PCM that reduces engine power
under certain conditions. Torque Management is performed for the
following reasons:
To prevent overstressing the power train components.
To prevent damage to the vehicle during certain abusive maneuvers.
To reduce engine speed when the IAC is out of the normal operating
range.
The PCM monitors the following sensors and engine parameters to
calculate engine output torque:
Air/Fuel ratio
Mass Air Flow
Manifold Absolute Pressure
Intake Air Temperature
Spark Advance
Engine Speed
Engine Coolant Temperature
A/C Clutch Status
The PCM monitors the torque converter status, the transmission gear
ratio, and the engine speed in order to determine if torque reduction
is required. The PCM retards the spark as appropriate to reduce
engine torque if torque reduction is required. The PCM also shuts
off the fuel to certain injectors to reduce the engine power in the
case of an abusive maneuver.
The following are instances when engine power reduction is likely to
be experienced:
During transmission upshifts and downshifts.
Heavy acceleration from a standing start.
The IAC is out of the normal operating range.
When the driver is performing harsh or abusive maneuvers such as
shifting into gear at high throttle angles or shifting the
transmission from reverse to drive to create a rocking motion.
The driver is unlikely to notice the torque management actions in the
first two instances. The engine power output will be moderate at
full throttle in the other two cases.
The PCM calculates the amount of spark retard necessary to reduce
engine power by the desired amount. The PCM disables the fuel
injectors for cylinders 1, 4, 6, and 7 in the case of an abusive
maneuver.
under certain conditions. Torque Management is performed for the
following reasons:
To prevent overstressing the power train components.
To prevent damage to the vehicle during certain abusive maneuvers.
To reduce engine speed when the IAC is out of the normal operating
range.
The PCM monitors the following sensors and engine parameters to
calculate engine output torque:
Air/Fuel ratio
Mass Air Flow
Manifold Absolute Pressure
Intake Air Temperature
Spark Advance
Engine Speed
Engine Coolant Temperature
A/C Clutch Status
The PCM monitors the torque converter status, the transmission gear
ratio, and the engine speed in order to determine if torque reduction
is required. The PCM retards the spark as appropriate to reduce
engine torque if torque reduction is required. The PCM also shuts
off the fuel to certain injectors to reduce the engine power in the
case of an abusive maneuver.
The following are instances when engine power reduction is likely to
be experienced:
During transmission upshifts and downshifts.
Heavy acceleration from a standing start.
The IAC is out of the normal operating range.
When the driver is performing harsh or abusive maneuvers such as
shifting into gear at high throttle angles or shifting the
transmission from reverse to drive to create a rocking motion.
The driver is unlikely to notice the torque management actions in the
first two instances. The engine power output will be moderate at
full throttle in the other two cases.
The PCM calculates the amount of spark retard necessary to reduce
engine power by the desired amount. The PCM disables the fuel
injectors for cylinders 1, 4, 6, and 7 in the case of an abusive
maneuver.
Launching!
Joined: May 2003
Posts: 290
Likes: 0
From: Canadian West Coast
Originally Posted by GOaT Cheese
In what form specifically? It is not simply retarding the timing during upshifts, that is just the computer anticipating a transitional spark knock. I had always understood that the full blown active torque management system used in the GTO and Corvette was introduced in '04, No? I am completely aware of the ASR and TCS systems, but both of those can be turned off by the driver, while the current torque management that I am asking about is burried deep within the ECU.
Earlier A4's definitely have a "form" of torque mgt, but as you pont out, mostly in the form of spark retard. My spark actually goes from 28 to -3 or -4 at the shift points, which is part of the torque mgt. I believe there is also a setting at the max level of torque allowable too, which is set at 350 ft-lbs, but I don't know how relevant that is. But I'm not an expert on this, and someone may have other info.
So most of our torque mgt is at the shifts only. Though trucks I BELIEVE are handled differently.
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
Originally Posted by GOaT Cheese
I know exactly what torque management is, my question was if it was used prior to '04 in its current form. Because I am only familiar with the TCS and ASR systems being used before '04.
Yes, it was used in earlier year vehicles. Haven't messed much with 04+ vehicles, but TCS/ASR are completely different than torque management.
The newer vehicles do use much more torque management (the LS2 trailblazers are ridiculous w/how much timing they pull), but older LSx based vehicles employed TM as well
