he didnt say which was better for offroading.
try locking your diff's then hitting a patch of dry ground and having to turn..
then some snow 1 mile ahead... then dry....
yea not the best system for on road.
sounds like you havent heard of X-drive either.
IMO AWD is far superior ON ROAD to conventional 4x4 "truck" type systems.
I've had both
4x4 is great but unless you have a center diff. you can have major binding
and dont try turning with front and rear locked you will get really bad handling characteristics on road.
living in ohio you should know this.
Living in Ohio, owning a vehicle with Torsen central differential and being a mechanical engineer, I know exactly what I'm talking about. I also used to drive a BWM with X-drive, and I am quite familiar with the system
Most AWD vehicles, including Subaru (and BMW), suffer from the same limitation. Torque is distributed to all wheels accordingly to a design pattern (50/50, 70/30, depending on designers preferences and objectives). That means that if one wheel ends up on a slipper spot and traction drops to an insignificant level, the amount of torque going to all other wheels drops proportionally INSTANTLY. Only AFTER the wheel on the slippery surface has started to slip and the computer has detected a difference in rotational speed, the system can intervene and redirect the torque to the wheels with traction. It takes only a fraction of a second, but the slippage of at least of one wheel is inevitable. Some systems are pretty "dumb" and can only deal with one wheel slippage (Honda CRV used to be that way, don't know about latest model), some can deal fine if the loss of traction is in a diagonal pattern (for example Toyota Highlander), some are very smart and can deal with up to three wheels loosing traction (Subary, BMW X-drive, Mercedes 4Matic). But regardless of how smart or dumb the computerized system is, it depends on the difference in rotational speed between tires, and this, by design, implies that one or more tires are slipping and hence are subject to dynamic coefficient of friction vs. static coefficient of friction (which is always higher).
The ONLY exception is a mechanical system based on a Torsen differential. A Torsen has the ability of directing torque based on difference in "resistance" instead of rotational speed. Torsen was first used by Audi in their Quattro system, and is used by Toyota in some of their better off-road vehicles (Land Cruiser, FJ Cruiser, Lexus LX and GX, 4Runner). The downsides of Torsen are:
- cost: a Torsen differential is more expensive than a software based system. All hardware required for a "smart" AWD system are already in place in any AWD vehicle equipped with ABS and electronic stability system. All you need is a little bit of software and you can create a system like X-drive or 4Matic with no additional physical equipment added. A Torsen adds a couple thousand dollars to price of the car.
- fuel consumption - because Torsen is a mechanical system that is always "on", it adds to fuel consumption by creating additional resistance when turning. It does not create any significant difference in driving "feeling" and performance, but adds a few % of extra fuel burn.
A "dumb" 4WD system like used in pick-up trucks and Jeep Wrangler indeed has the inconvenience of being a part-time system that has to be turned off most of the time. But once you get in serious snow, it WILL perform better than most electronics-based systems. With a Torsen, you have the best of both worlds - full-time AWD, plus user-selectable option to switch to "hard" 4WD. But that's why Lexus, Land Cruise and Audi Quattro cost more than a Subaru. You get what you pay for.