hemidup
Senior Member
- Joined
- May 3, 2014
- Posts
- 150
- Reaction score
- 41
- Ram Year
- 2005
- Engine
- Supercharged 6.4 Hemi
I deal directly with Chrysler engineers when it comes to transmissions. I asked him about tq management in modified to high HP applications. Here's his reply:
Torque management definitely helps to extend clutch life, by limiting the amount of energy absorbed during a shift (and therefore, the peak clutch temperature).
Energy generated is directly related to the clutch torque capacity and the slip speed. We typically target a certain speed change rate (which determines the length of the speed change). The clutch apply pressure is adjusted during the shift to try to hit our target speed change rate. Since the slip speed profile is fairly constant (if we are truly following the desired speed change rate), the energy absorbed will vary depending on the clutch torque level. And the clutch torque level required depends on the amount of input torque. So higher input torque = higher clutch torque capacity required = more heat generated. Likewise, if we reduce (limit) the engine torque during the shift, we can use a lower clutch capacity (less apply pressure) and therefore produce less heat in the clutch.
I’m thinking that to handle all the increased torque, you will need some kind of trans tuning. Ideally, you would raise the line pressure targets, change the clutch speed change rates (to give faster shifts, within reason), and then dial in the proper amount of torque management.
Torque management definitely helps to extend clutch life, by limiting the amount of energy absorbed during a shift (and therefore, the peak clutch temperature).
Energy generated is directly related to the clutch torque capacity and the slip speed. We typically target a certain speed change rate (which determines the length of the speed change). The clutch apply pressure is adjusted during the shift to try to hit our target speed change rate. Since the slip speed profile is fairly constant (if we are truly following the desired speed change rate), the energy absorbed will vary depending on the clutch torque level. And the clutch torque level required depends on the amount of input torque. So higher input torque = higher clutch torque capacity required = more heat generated. Likewise, if we reduce (limit) the engine torque during the shift, we can use a lower clutch capacity (less apply pressure) and therefore produce less heat in the clutch.
I’m thinking that to handle all the increased torque, you will need some kind of trans tuning. Ideally, you would raise the line pressure targets, change the clutch speed change rates (to give faster shifts, within reason), and then dial in the proper amount of torque management.
