Can someone explain this to me?

 

I am not going to take credit for this because it would take a while to type all this, but this is a good explanation...

The first question that needs to be addressed is, What is Torque Management (or TM and many refer to it)? TM is part of the programming in the PCM (powertrain control module) that ultimately reduces engine torque when the transmission changes gears. Its purpose it to increase the longevity of the transmission and drivetrain as a whole.

What cars have TM?
All automatic transmission F & Y body cars have TM reducing engine torque during gear changes. Please note that TM is only "active" is automatic transmission cars ( F & Y body). Manual transmission equipped cars do not make use of TM as the average manual driven car has a different kind of power reduction during gear changes. When the average Joe is driving along and goes to make his 2-3 shift, his right foot comes off the throttle, his left foot dis-engages the clutch while he changes gears via the shifter. Once the shift is done the clutch will be re-engaged and the throttle will be depressed once again. Therefore, TM is not necessary in manual equipped cars, as the average way that a manual is driven has a sort of self imposed torque reduction. Note, this is the way the "average" person drives, not the way a lot of us drive.


How does TM vary by year?
While its operation is generally unchanged, the amount of torque reduced and the speed at which it is reduced varies. Generally speaking, Earlier models (98-99) reduce engine torque a little earlier but ultimately can reduce torque by up to 30%. Again, in general, later models (00-02) reduce torque a little later, but can ultimately reduce engine torque by up to 37%. More on this to come.


So how does TM work?
All of those wonderful sensors that allow your engine to operate so well also supply the inputs that allow TM to function. While I am not going to get into what all happens mathematically, the PCM calculates the "Delivered Engine Torque" based on numerous inputs. The PCM then retards ignition timing to reduce engine torque by a predetermined percentage based on the engine's torque output. Since a picture is worth a thousand words, the below image shows the table in EFILive's FlashScan for the 1-2 shift in an '00 Camaro, automatic transmission obviously. Keep in mind that different years have slightly different values, so don't worry if your values do not match these.



As you can see in this image, torque is reduced by 5% when the "delivered engine torque" is 207 ft/lbs, (for example). As you can imagine the more power you make the more TM reduces during the shifts. This next image shows the torque reduced during the 2-3 shift.



There is no torque reduction for the 3-4 shift, nor is there torque reduction during downshifts. This is why WOT downshifts are harsh on the transmission.

This next image shows TM in action in my '02 Trans Am on the 2-3 shift.



As you can see, the ignition timing was up at 30* right up to the shift. When the transmission shifted, the timing was reduced to 7.5*, making for a nice shift that is not too harsh on the transmission. After the shift was completed, ignition timing was bought back up to "normal".

This next image shows the same shift on the same piece of road with TM "removed", (set to 0% reduction).



As you can see, timing is maintained through the 2-3 shift and the car continues to pull through the shift, whereas with TM still enabled, you can feel the car ease off for a fraction of a second before pulling again.

And the biggest question of all... What does all of this mean for me? It all comes down to personal preference as to if you want to leave it or alter the programming. I found that I like the feeling of no torque reduction, so I have "deleted" it from the programming. Now that you know the basics in its operation you can make the educated decision as to if you want to keep it or remove it.