Another Q on the 8 speed ZF auto box. Can anyone point me to a guide as to how the algorithms work?

Light throttle opening seems to give upchanges at lower revs, and more gas = upchanges at higher revs. To get the best out of the box however (sorry, getting very anal now) I'd like to understand how it makes its decisions.

Also the centre diff on the HSE is described as being a Torsen type. Anyone have any more technical info on this? I have a car (Caterham 7) with a Quaife LSD - is that a similar concept?

Thanks all.

The transmission reacts to your intentions as you express them via your right foot. It interprets both the depth of the pedal movement and the speed of the movement. The shift logic is immensely complicated and to make things more complicated, it is a self-learning mechanism so each car behaves differently.

Quaife is a diff builder, Torsen is a trademark name for a specific type of helical limited slip diff, so this is z question that should be asked differently. Your Quaife diff can be helical, can be plate-type, can be Torsen-like… IDK. Regards etc.,

Wojtek

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WAS: 2006 RRS Supercharged
IS: 2010 RRS TDV8 HSE

As TheWojtec really - it's a learning algorithm that has a base map and then adjusts to the driver inputs over the last 30 miles or so. Hence if you drive agressively, it will hold gears longer and be more eager to kick down. If you drive like Miss Daisy, it will change up earlier and be less eager to come back down.
This is why sometimes you can catch it out. I've had occasions with the HP8 where I've been driving economically and decided to overtake something, only for it to be quite reticent to kick down. Equally, I've driven enthusiastically for a while, and then needed to use the paddles to get it to change up as it was holding onto gears.
I would imagine the base code is the IP of ZF and they'd not be happy for it to be published (not that most of us would be able to glean anything from a binary map). 2021 L494 D300MHEV Autobiography
2019 Discovery Sport D180 HSE

The centre diff on the single speed transfer box is a planetary type torque sensing differential. Normally, torque is split 40% f/ 60% r but can be diverted up to 65f/35r or 20f/80r. It works by using internal friction to direct the torque to the front or rear shaft.

On the two speed transfer box, the centre diff is a multiplate clutch capable of infinitely variable adjustment so you can have all the torque to one or other axle if required, this is because it is a fully locked diff when fully engaged. Normally it runs 50% f/50% r like a normal open diff would.

Quaife's LSD for the 7 appears to be a helical type so basically the same type as the one in your RRS. They are torque biasing units rather than locking units. Neither the single speed RRS nor the 7 will "lock the diff", there will always be relative motion between the two sides of the diff.

Interestingly, the early L322 Range Rover used a torsen centre diff but this was changed over to the multiplate units used by the L319 Discovery and L320 RRS in 2006 presumably because of Terrain Response being added which is involved in control of the centre diff locking function. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed