This has made me ponder, i always disconnect my VDC when driving on the beach because ive heard the system makes the car a pig in the sand and will get you bogged...
But would it? Wouldn't the VDC help overcome wheels that are stuck and help you get out of a bog easier?
Or am i thinking silly
Dunno if you're thinking silly, necessarily - we've got an '07 Outback Wagon (H6, 5EAT) in the family with both VTD and VDC, and I
hate VDC in the dirt.
There's one section of forest trail where VDC turns the car into a one-wheel-drive wonder: it's an uphill, slightly off-camber stretch of firm, washboardy dirt with gravel on top of it. That particular combination brings the OBW to nearly a dead halt as the computer goes insane trying to figure out what the wheel sensors are telling it and where to send power as a result. Note that this is somewhere I used to take my Brat/Brumby through in FWD with no issues, so it's not like this is seriously difficult terrain. The only way to make the OBW behave is to switch traction control off, which disables VDC - once the car is in 'dumb and dangerous' mode, it's perfectly controllable.
One other situation I've seen it behave strangely in is fresh snowfall (approximately 4"-5") on top of ice-free pavement. Parked it in the middle of an empty parking lot (judging from the lack of tyre tracks, I was the first one in there after the snow started) and tried to take off from rest, gently. The car moved at about a 30-degree angle to straight ahead in what I can only describe as a crab-like motion as power was redirected. Repeated this experiment in a couple of other similar locations and got very similar results. Turned the traction control off and everything was A-OK.
My opinion is that VDC works well in a narrow set of circumstances (wet or dry pavement, basically), but get outside of those specific circumstances and its shortcomings very quickly become apparent. Can't speak as to how it is on sand as I've never taken that car on the beach, but if I were going to, the traction control button would be the first one I'd press after finding the gate that lets you get down to the water
VDC and EBD are completely different systems. VDC splits power between the wheels whereas EBD splits braking between the wheels.
Not quite, unless something's different for the Australian market. VDC stands for 'Vehicle Dynamics Control', where various pitch, yaw, speed, brake, etc. sensors are read and braking, etc. adjusted to keep the vehicle upright. It's essentially another name for stability control. VTD is Variable Torque Distribution, which is one of the methods by which power is transferred between the front and rear axles in automatic-equipped Subarus. VDC and VTD do work in concert on vehicles equipped with both, however. You were bang on with EBD, though
