4L60E tuning in $0D

[Fast355]

First I would like to say is this. The XDF files are NOT what actually came from the calibration. They are reverse engineered and they have mistakes. Addresses and verbiage. Scaling of variables can be off. You see this in what you are describing and have missed how the trans pressures are set in the calibration.
The calibration value 0 to 90 is actually a PTS. Pressure Torque Signal. The pressure the force motor makes on the Pressure regulator line up. Plus the area and the spring pressure in each selector range except in Reverse where the Rev boost compounds the pressure to a higher value. So you say the trans runs at 200 PSI but the cal is 90. 90 PTS not PSI. This is where the reverse engineered XDF's have you at a disadvantage. I have not sat and compared each value in these reverse engineered files and won't. It takes to much time and there are many calibrations missing.
You can have a 4L80-E in Drive Range and the calibration at the given place is 90 PTS. The Trans Line Pressure in PSI will be aprox 170 PSI measured. If it is in Reverse it is much higher as you can easily see in a hydraulic flow chart. This will help explain what PTS is and PSI are when you are calibrating the transmission. I hope this make sense.

Which IMO is the reason you should really attach a hydraulic pressure gauge when calibrating the line pressure tables. With the plethora of stock and aftermarket pressure regulators, springs, field adjusted EPC solenoids, etc it is entirely possible to have too little or too much pressure.

[1BadAction]

First I would like to say is this. The XDF files are NOT what actually came from the calibration. They are reverse engineered and they have mistakes. Addresses and verbiage. Scaling of variables can be off. You see this in what you are describing and have missed how the trans pressures are set in the calibration.
The calibration value 0 to 90 is actually a PTS. Pressure Torque Signal. The pressure the force motor makes on the Pressure regulator line up. Plus the area and the spring pressure in each selector range except in Reverse where the Rev boost compounds the pressure to a higher value. So you say the trans runs at 200 PSI but the cal is 90. 90 PTS not PSI. This is where the reverse engineered XDF's have you at a disadvantage. I have not sat and compared each value in these reverse engineered files and won't. It takes to much time and there are many calibrations missing.
You can have a 4L80-E in Drive Range and the calibration at the given place is 90 PTS. The Trans Line Pressure in PSI will be aprox 170 PSI measured. If it is in Reverse it is much higher as you can easily see in a hydraulic flow chart. This will help explain what PTS is and PSI are when you are calibrating the transmission. I hope this make sense.

Like all of Billys posts about these transmissions, this one is GOLD!


On tuning: I have done more trans tunes than I have engine tunes, most of them on 4L60Es in LS vehicles, but the basics have always been the same. Start with shift times. Lower them in the 1-2 and lower or zero them in the 2-3-4. Then adjust shift points. THEN if it feels a bit soft in the shifts, bump up the pressures a few PSI. Finally, clean up any light throttle shifts that are too quick/harsh. If done right it'll drive like a completely different vehicle.

I really prefer to leave the pressure alone in the tune and have a shift kit and (sometimes) servo installed to firm up the shifts, but that is a totally different discussion.

[lionelhutz]

First I would like to say is this. The XDF files are NOT what actually came from the calibration. They are reverse engineered and they have mistakes. Addresses and verbiage. Scaling of variables can be off. You see this in what you are describing and have missed how the trans pressures are set in the calibration.
The calibration value 0 to 90 is actually a PTS. Pressure Torque Signal. The pressure the force motor makes on the Pressure regulator line up. Plus the area and the spring pressure in each selector range except in Reverse where the Rev boost compounds the pressure to a higher value. So you say the trans runs at 200 PSI but the cal is 90. 90 PTS not PSI. This is where the reverse engineered XDF's have you at a disadvantage. I have not sat and compared each value in these reverse engineered files and won't. It takes to much time and there are many calibrations missing.
You can have a 4L80-E in Drive Range and the calibration at the given place is 90 PTS. The Trans Line Pressure in PSI will be aprox 170 PSI measured. If it is in Reverse it is much higher as you can easily see in a hydraulic flow chart. This will help explain what PTS is and PSI are when you are calibrating the transmission. I hope this make sense.

No, I didn't miss how the transmission pressures are set in the calibration. As I posted, the xdf says psi in a number of places but all the tables and scalars for the line pressure are not psi. The tables all work together to come up with a number that refers back to the force motor tables and then the force motor current from the table is applied to the force motor. The current in the force motor is what sets the line pressure. PTS is nice to know but it doesn't really matter what it's called as long as everyone realizes what is actually happening.

In $EE increasing the maximum pressure scalar (the one normally set to 90 "psi" actually causes the line pressure to drop. I suspect the same would happen in this calibration.

Yes, the reverse pressure is different but I never bothered to mention the reverse pressure being high, because it is what it is and doesn't affect the pressure during normal forward driving (pressure when shifting and pressure between shifts).

I already knew that the xdf files for the older stuff all come from reverse engineering the calibration code.

[Fast355]

No, I didn't miss how the transmission pressures are set in the calibration. As I posted, the xdf says psi in a number of places but all the tables and scalars for the line pressure are not psi. The tables all work together to come up with a number that refers back to the force motor tables and then the force motor current from the table is applied to the force motor. The current in the force motor is what sets the line pressure. PTS is nice to know but it doesn't really matter what it's called as long as everyone realizes what is actually happening.

In $EE increasing the maximum pressure scalar (the one normally set to 90 "psi" actually causes the line pressure to drop. I suspect the same would happen in this calibration.

Yes, the reverse pressure is different but I never bothered to mention the reverse pressure being high, because it is what it is and doesn't affect the pressure during normal forward driving (pressure when shifting and pressure between shifts).

I already knew that the xdf files for the older stuff all come from reverse engineering the calibration code.

I have not actually looked, but I am sure increasing the max pressure constant would decrease line pressure as well.