4L80E Shift Tuning

A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
Post Reply
flak monkey
Posts: 50
Joined: Sun Sep 21, 2014 11:28 am

4L80E Shift Tuning

Post by flak monkey »

Took my Camaro for it's first drive today, the motor is running well (MS3X) but I really need to dial in the transmission so I can drive it any distance.

I'm getting a good solid VSS signal, so that's something! :D

I have attached my current MSQ.

2 real issues:

1. I have very firm shifts - this may be as a result of my Transgo HD2 shift kit, but they are still a lot firmer than I would expect to be honest, especially at part throttle. Other than the shift pressure settings is there any way to smooth these out at lower loads?

The line pressures at idle are as below, and I know that the PC solenoid is working as I could vary these by changing the duty cycle in TS with the engine running.
Park 120psi
Neutral 125psi
Reverse 280psi
Drive 180psi
3rd 175psi
2nd 175psi
1st 175psi

2. I'm not seeing much movement in the load percentage on the table as I drive, meaning I can't really tune my shifts very well.

If I wanted to switch to pure TPS mode if I move the Map vs TPS slider all the way to the left and then alter the TPS load table so that each percentage is directly transcribed is that all I need to do?

I think pure TPS is going to work much better in my application - most of the after market controllers and GM only used TPS and the load factor on the 4L80E too.

Do I need to change any settings anywhere else to get pure TPS?
(61.96 KiB) Downloaded 1691 times
Post Reply