I am wondering about what would be the behavior of the car in a cross axle situation.

I would expect that the ABS & DSC/ETC system are used to apply brakes on wheels with no traction in order to have torque being sent thru axle diff to the wheels with traction.
However, after watching a few videos of FL2 off roading, it looks like it is not really the case.

Has anyone experienced that ?

Bear in mind that I've only had one off-road session and this info was given to me by the Landrover instructor, so here's my understanding...

Unlike the other LR's the FL2 uses only software to control the power to the 4 wheels. In situations of reduced/variable traction the engine will always initially send power to the route of least resistance so you will notice considerable wheel spin in an offroad environment.

However once the power reaches a certain level, I was told between 1500-2000rpm, the computer reassesses this and applies some braking pressure to the freemoving wheels and redistributes the power to the other wheels which should have greater grip to move the vehicle.

I ascended a steep incline straddling wet grass under passenger side wheels and mud under my side and this is exactly what happened in that scenario. P/S wheels slipped like a very slippy thing and kept doing so until I increased the revs to about 2000rpm then power went to my side, grip restored, reached top of hill, job done!! In fact when we looked at the tracks from the bottom of the slope you could see where the transfer of power occured due to the different appearance of the ground below. Cool

If this is wrong I'm sure somebody wiser and definately older will be along shortly!!

Joe MY11 Fuji white Td4 150 GS straight up no mixer.

Think its the same as FL1, you will need to get those revs up a bit before it sorts itself out.

What you describe is what seems to happen on the video I saw.
The car was stuck with wheels "in the air" turning, then it got some traction and went passing the obstacle.
Was not sure if it was the TCS applying brakes on wheels with no grip or both wheels on the other side getting grip at some point thus having three wheels with grip.

All the gizmos work very well, I've had my car on two wheels (cross axle) quite a few times and the gizmos stop the airborn wheels and drive the others. However there is a certain amount of wheel spin before the systems kick in ... but it does work very well .... ask Carl he was watching from behind ..(his favourite position !!)

The situation is most apparent in the LR video which demonstrates this, the one in Iceland I think, on a half tarmac/ice slope. It worked for them too!

On any of the modern Landies the cross axle problem is almost impossible to achieve as the car's TC should not let it occur. In the old F1, you needed 5 wheel rotations before TC and HDC would cut in, progress means that now the electronics cut in even sooner. This situation is one of the things that you are shown at the LRE days, with the 2 diagonally opposite wheels flying - my non TC equipped Defender would be totally stuck if I tried the same thing in it. How can carbon have a footprint, it has no feet?
Now driving - RRE Coupe Dynamic Lux Auto with Plus pack, Fuji White, Ebony, SD4 with tow pack
Gone - 2010MY FFRR TDv8 Stornoway and Ivory, Privacy - the pace of a TDv8 RRS, the incomparable grace of a Range Rover
Gone but will be missed- RRS Tdv8 HSE Stornoway Grey with Ebony Leather
Gone (only a little missed) RRS Tdv6 2.7SE Giverny Green/Aspen
Defender 90 County HT in Epsom Green

There is some LR publicity material that talks about one of the gizmos (TC?) cutting in after just 15 degrees of wheel rotation, if you get into the cross axle/two wheels off the ground situation then it certainly takes much more than 15 degrees of movement before the wheel spin is arrested. But once you have expereinced this situation a couple of times you get a 'feel' for how much power/revs you have to feed in to get the systems working. For me I know it was the demonstration at LRE events that helped me learn about this and gave me the confidence to try it myself in other situations.

avtur wrote:

There is some LR publicity material that talks about one of the gizmos (TC?) cutting in after just 15 degrees of wheel rotation,

Thx guys.
What I read here gives me some confidence now that if I have such a situation the car is able to make it.
Now, the question is about my own skills
I have the car since July, and my dealer has my LRE planned for June next year
Plenty of time for having problems before being trained.

Tim in Scotland wrote:

my non TC equipped Defender would be totally stuck if I tried the same thing in it.

Can anyone provide a detailed rundown of how the 4wd system in the FL2 works?

I've heard a few different versions which don't all agree so I'd like to clarify.


Cheers,

nicam wrote:

But the Defender would probably have kept its wheels on the ground over the same terrain, thus getting grip in the old fashioned way.