PID TRQTRANS, good bad or ugly?

[Blacky]

BOBFO - I have been measuring the delivered engine torque and the trans torque. BTW the flywheel power uses the delvered engine torque.

Blacky - I thought there was a torque sensor measuring turning force on the drive shaft. Is this not the case? Since I have an auto torque values effect shifts and I have been keen to understand what the PCM thinks the torque is as desired shift times and trans pressure is calibrated using torque values.

I do admit it is pretty good as I have programmed the VSS changes how I like, but I do not understand when the torque values are used to determine shifts (ie D1108-D1110 & D0701-D0703).

Thanks,

As far as I know, there is no torque sensor in the LS1 powertrain, well not one that is used by the PCM. If anyone knows differently please correct me.

All the torque PID values are calculated from other sensors and preset calibrations.
The shift times can be controlled by changing the transmission line pressure. The pressure (and therefor the shift times) can be calibrated based on the PCM's estimated torque delivery to the transmission.

Some (not all) PCMs are configured to adapt the line pressure (D0701-D0703) based on the desired shift times (D1108-D1110).

You can see the learned adapt-shift values in the EFIlive Scan Tool.
Menu: LS1/LS6->Auto transmission adaptive shift cells.

Even if the delivered torque values are not calculated 100% accurately, the PCM (if configured to) may "learn" the correct pressure to use to obtain the desired shift times.

Regards
Paul

[daveb]

thanks I'll try that.

DAVE