911 carrera 4

[Geffg]

Friend of mine has a 1992 Porsche 911 carrera 4 and I was saying other day about putting it in 4wd due to the snow and ice as it’s used daily. The answer was they didn’t know how to. Only had the car 12 yrs.
Spoke to them earlier and they said they tried this morning but didn’t hear anything kick in just a light flashed.
Anyone know the procedure and does anything show up to say it’s in 4wd? Also can it be driven normally like this or is it only up to a certain speed?

[First Sea Lord]

It will permanently and automatically use its 4WD system at any speed. No scope to turn it on / off manually

The system itself switches between 2WD and 4WD as needed if I remember correctly

[wax lyrical]

That's correct. It's permanent 4-wheel drive with most of the power going to the rear wheels in normal conditions/normal driving. The car decides when more power is needed to go to the fronts (depending on conditions) and switches seamlessly, as required.

First Sea Lord said:

It will permanently and automatically use its 4WD system at any speed. No scope to turn it on / off manually

The system itself switches between 2WD and 4WD as needed if I remember correctly

[Orangecurry]

This is a likely correct information from someone on PCGB

internet said:

......the torque split IS 31/69 under "normal" driving conditions. On the 964 C4, the AWD system uses a mechanical centre differential, unlike the later 993 and 996/7 cars which use a torque sensing diff. Outside of the "normal" driving conditions the C4's PDAS (traction control) system will take control of the diffrential locks to vary the drive according to it's movement sensors - a system which is completely automatic and not controllable by the driver, with NO facility to disable it. Rest assured, there is NO need to disable it since it works very well.

The rotary switch you mention on the centre console is the diff lock actuation switch. If you get into a situation where traction is difficult, like loose snow or mud, the diff lock can be engaged to improve the traction. This diff lock will automatically disengage over speeds of 40kph. The small yellow light above the diff lock switch is the PDAS activation light - which will flash when PDAS normally activates in slippery conditions and will come on permanently when the diff lock is activated manually.

BTW, because of the mechanical AWD system, a 964 C4 should NEVER be towed with only 2 wheels on the ground and should NOT be run on a 2WD rolling road. In the same vein, don't be talked into disconnecting the front drive shaft to enable the rears only to drive a 2WD rolling road - is doesn't work!!!

[Geffg]

Thanks for the quick replies and info I’ll let them know.