View Single Post
      10-17-2019, 08:18 PM   #24
EstorilM240
Private
114
Rep
87
Posts

Drives: 2017 M240i 6MT
Join Date: Jan 2019
Location: California

iTrader: (0)

Quote:
Originally Posted by MassNerd View Post
That article has some gaps which I'm curious to know.
#1: Why would middle of the range (4th for the 6 speed, 3rd and 6th for the 8 speed) have lower torque limits and lower line pressure? That doesn't seem to make sense? Maybe a gradual decrease in limits as you go up the gears would make more sense? I would be surprised if BMW and ZF just randomly tuned the transmission that way.
I read this deep dive a while back on the theory of the ZF8 and found it interesting: https://www.thetruthaboutcars.com/20...eed-automatic/. I suspect the limits have something to do with the particular gear sets driven and the torque transfer.

5th in the 6 speed (not 4th) and 6th in the 8 speed both have the low torque limits, and both are the 1:1 drives... Perhaps transferring torque through fewer gear sets = lower mechanical limits? Any mechanical engineers care to chime in?
Appreciate 0