Quattro vs xDrive Q5, X3

[bawareca]

Just advertisement with this symetrical-non-symetrical AWD.X-drive will react the same way as the Subaru did.I have tested it with the X3 back in 2005.

[JCL]

Originally Posted by AlexK

To be fair, even with "real life" snow and no silly metal contraptions with roller bars the same thing can be observed on "cars with Torsen"

Yes, unless there is an electronic traction control, or the driver knows to put his/her foot on the brake when one axle has no traction.

I've driven Audi awd vehicles (some years back), and always thought they did fine in the snow. But the videos above are all exploiting the same specific point, that a driver that doesn't know when to apply the brake can get stuck.

[JCL]

Originally Posted by AlexK

Well, most modern AWD systems on "on-road" SUV/SAV/cars are designed so the driver doesn't have to do any unusual manipulations in order to make them work efficiently. Not everybody needs to know (or care to know, as it is a case of majority of drivers of certain sex or age groups ) how the system functions in order to make the system fully functional. In that way, Mercedes' 4matic and BMW's xDrive are superior since they do most of the stuff automatically regardless of traction control button's position or brake pedal's position.

I am not sure I would use BMW as an example of enlightened awd system control design. They have a button labelled Traction Control (DTC), which when you push it, reduces traction. Not only isn't it automatic, it is backwards. Other models use a 4x4 light for DTC, suggesting that if you don't push it you have 4x2. If they wanted to play to their customer base, most of whom don't seem to read the manual, they would get rid of the button.

[JCL]

Originally Posted by AlexK

Pressing the DTC button on xDrive-equipped vehicles don't affect the front-rear torque distribution. A single momentary press merely allows more wheelspin without reducing engine output, while still applying brakes to individual slipping wheels. The "long press" goes even further, disabling the slipping wheel braking. There was a BMW's TIS document with detailed description, I don't have it anymore, I'm sure anyone who still has access can post it... Anyway, I highly doubt that you would get "stuck" in similar way (as in videos with Audi) regardless of DTC's button position, simply because xDrive can still simply transfer 100% of torque to whatever axle that has most grip.

I know what pushing the button does

In reference to "the majority of drivers who don't want to know how it works" it is backwards, ie it reduces traction. On those balance beam tricks, it would have reduced the vehicle's awd performance.

Try that "long press" and let us know how it works for you. It was a feature on our E46 325xi, it wasn't on our X5. It appears to be an internet urban legend these days.

[JCL]

Originally Posted by AlexK

It works the same way as I described. X5, at least 2010 E70, still has same exact function as my 2009 328xi

Sorry, I was discussing the E53.....this being the E53 forum and all.

[TheGodfather]

Some more BMW Xdrive "propaganda"
YouTube - BMW X3 xDrive 2010 2011 contre Audi Q5

Somewhat dated video:

Quattro vs 2001-2003 X5 et al. up what looks like a ski slope.
http://www.youtube.com/watch?v=EyKstZ6a5ag

Top Gear:
X6 vs Range Rover. X6 fails.
http://www.youtube.com/watch?v=x7nGXpqb3FE

Even if these tests are not definitive, they are entertaining none the less!

[AzNMpower32]

Average drivers don't even know there's a DTC mode on the BMWs. Including both my parents. Nor do they care.

[phil47]

Originally Posted by TheGodfather

Top Gear:
X6 vs Range Rover. X6 fails.
YouTube - BMW X6 Xdrive fail vs Land Rover Top Gear

Even if these tests are not definitive, they are entertaining none the less!

I remember seeing that Top Gear episode. I'm no fan of the X6 but I remember thinking that failure was clearly about the high performance tires on that model of X6 than a test of the Xdrive system. Locking diffs and ride height would not have helped the X6 in either case but that's what he refers to as the weakness. Like you said, it's all about the "entertainment value".

One day an independant outfit (Consumers Report? Car and Driver? Automobile? Motorweek? ) is going to do a reasonable, objective evaluation of current AWD systems under real world conditions (similar tires, similar class of vehicle, same driver, etc., etc.). I'd love to know who comes out on top