permanent awd

[Backhill1]

I understand that for towing more drive is sent to the rear wheels when you connect the tow bar electrics. I dont know the exact % but the exct same system is used in the modern 4 motion system that volkswagen and Audi use.This haldex system is used in most 4x4 vehicles most sucessfully in the freelander. The reason its so good off-road is that it is biased to 4x4 upon take off and doesnt wait for a wheel to slip to engage.
Therfore you dont get stuck in the first place.
I have not tested the theory but after last winter intend to keep a trailer board in the boot as the whole waiting on a wheel to slip is a joke on ice and snow.
The computer just thinks you are driving and does hee haw to help you. By which time your wheels are now on sheet ice.

[JamesV70R]

Plugging in towbar electrics doesn't affect the AWD as far as I know. Nor should it.

The car detects the front wheels are slipping so transfers power to the rear wheels through a diferential of some form or another. I think the max power transfer is a 70/30 split.

Also from a personal view, the freelander isn't exactly "capable" offroad. Just my own experience while offroading in the Discovery ... we had to save more of them from the mud than anything else

[Clan]

Originally Posted by Backhill1

I understand that for towing more drive is sent to the rear wheels when you connect the tow bar electrics. I dont know the exact % but the exct same system is used in the modern 4 motion system that volkswagen and Audi use.This haldex system is used in most 4x4 vehicles most sucessfully in the freelander. The reason its so good off-road is that it is biased to 4x4 upon take off and doesnt wait for a wheel to slip to engage. Therfore you dont get stuck in the first place.
I have not tested the theory but after last winter intend to keep a trailer board in the boot as the whole waiting on a wheel to slip is a joke on ice and snow.
The computer just thinks you are driving and does hee haw to help you. By which time your wheels are now on sheet ice.

volvo use this , it is called " Instant-Traction" .

regarding waiting for a wheel to slip , it is literaly one spoke movement on the wheel rim, not exactly waiting for the wheel to spin ..

[Backhill1]

I agree that normally this works but i find on snow and ice as both wheels are turning and the vehicle registers speed the computer thinks the car is driving normally. With my V70 i found you had to jag the throttle to up set the balance to get the traction control light flashing then the rear wheels started driving. Maybe mine is just a bit lazy.
I think instant traction (same as freelander) is only available on the XC range but i might be wrong. The data re the tow bar electrics came from the supplying Volvo dealer as i had concerns over towing with a front wheel drive biasd car i will have this checked with Volvo as this was my understanding.
Any way once i put some good chunky tyres on i have to say it was very good in all conditions and never again became a problem (touch wood).

[T4Rick]

Originally Posted by 850Rick

Doesnt the gearbox from the focus rs use the same box as the earlier rs?

There is a thread on on Vpcuk where a bloke on there has mated a cozzy box to a focus rs enginei wonder what it would look like fitted in the volvo 850 in 4wd

[Gazdok]

A company in North America modifies Haldex controller boxes to alter the bias to a sportier AWD / 4WD. They are succesful with all the VW / Audi / ... ones, but when they wanted to do Volvos they were stopped by ... guess who .. Volvo.

Also Haldex sell VW controllers with a different software. They have different agreements but Volvo apparently stopped Haldex from this little side business.

The hardware - diff, Haldex clutch, axles - would take the extra power.