Ah! The wheel with the rope round it is a brilliant idea! Yes, that would give you a pretty constant torque. (Although how on earth did you get a metre diameter wheel into the wheelarch)?! Did you have something like a tractor wheel bolted to the outside of the road wheel to get it clear of the bodywork or something? Just out of interest, when you use the rope, is your graph a straight line? Does the VCU (or should I say, does a healthy VCU!) have a linear characteristic, or is there a step in it above a certain speed? When you say you've had enough torque on there to "activate" it, I'd always imagined that these things had a fairly linear response so that the faster the speed the greater the torque and that torque would be proportional to the speed, but does there come a speed where it suddenly just "locks"?
This is all interesting. The Freelander replaces a Nissan X-Trail and they have a completely different 4WD system. There's a multi-plate clutch in the nose of the rear diff which is electrically actuated, so you can have a switch on the dash for 2WD, "Auto" and "Lock". I thought that was a better system than the viscous one that LR use, and true enough, it was one of the few parts of the X-Trail that never gave us a minute's bother in the whole time we had the car, but from the little bit of driving on mud and wet grass that I've done, the Freelander does seem to have better traction!
Thanks you so much for doing this. It's a really valuable resource.
P.S. I think you can neglect acceleration completely. Certainly at the speeds I've been looking at, it's been negligible. If anything, if you wanted to "finesse" it more, might the weight of the bar itself be the next thing to try and account for?
