Originally Posted by PropellerHead (Post 959234)

I drove a 10/2004 model for nearly 7 years. I loved that thing. Early 2004 X5's (including yours) have XDrive. A change to the standard all wheel drive of the pre-facelift. X Drive can put 100% of the engine power to the one wheel it senses with traction. The older ones were static 48/52.........

Originally Posted by TiAgX5 (Post 959991)

Not the case. Pre-facelift Xs were able to direct 100% of torque to front/rear axles and side to side using automatic brake activation.

Originally Posted by PropellerHead (Post 960012)

I'd like your source on that one. Everything I have seen including my experience with a 2001 X5 since new and the two Xdrive 2004's is different. If you're saying it's 100% of *available* torque, that would be correct, but the available TQ to front and rear is not 100% of the engine power in the earlier cars. The later cars transfer allows this.

Also, I am reading I had the earlier ratio incorrect. Still fixed, but fixed at 38/62.

The video shows an X5 with ZERO grip on all wheels. The later portion of the video shows that the other wheels are spinning at the same rate or close to it until the braking kicks in. This happened quite a bit on my '04 3.0 in the snow and would be expected in that case.

Originally Posted by PropellerHead (Post 960012)

I'd like your source on that one. Everything I have seen including my experience with a 2001 X5 since new and the two Xdrive 2004's is different. If you're saying it's 100% of *available* torque, that would be correct, but the available TQ to front and rear is not 100% of the engine power in the earlier cars. The later cars transfer allows this.

Also, I am reading I had the earlier ratio incorrect. Still fixed, but fixed at 38/62.

The video shows an X5 with ZERO grip on all wheels. The later portion of the video shows that the other wheels are spinning at the same rate or close to it until the braking kicks in. This happened quite a bit on my '04 3.0 in the snow and would be expected in that case.

Originally Posted by TiAgX5 (Post 960015)

The TC torque split on pre-facelift was 38%f/62%r while driving without tire slippage. When slippage was detected the brakes on the slipping wheels were activated automatically which transferred torque to the wheels with grip. Not sure of the absolute limit BMW programmed into the system.

Originally Posted by bcredliner (Post 960021)

I don't know the absolute % either and don't why it would be less than 100% at the wheels that aren't spinning.

Originally Posted by TiAgX5 (Post 960022)

I don't see why seeing how all modern cars/trucks are required to have braking systems that can overcome the max torque produced by their powerplants.

Originally Posted by PropellerHead (Post 960029)

Because it was based on the the legacy AWD system that had been in use since the early iX cars from the 80's. On the early X5's, this is a planetary gearing that fixes the amount of TQ/power to the front or rear axle. In the early X's- 38 Front:62 Rear. Front rear power/TQ transfer is not programmed at all in the early X5's. It's fixed by the gears.

Xdrive uses a multiplate clutch system on the output side of the transmission that allows the system to modulate/vary the amount of TQ between the front and rear axles. XDrive computer control is able to activate this clutch within something like 1/10 of a second for up to 100% to the front or rear axle. The drive is normally split at 40F:60R for XDrive cars.

It is a significant difference from the early/non facelift cars. XDrive is one of the main reasons I bought one in 2004.

Originally Posted by TiAgX5 (Post 960031)

The torque split is fixed by the gearing UNTIL brake actuation causes the torque to the slipping axle to TRANSFER to the non-slipping axle.

Well aware of how Xdrive works.

Originally Posted by TiAgX5 (Post 959991)

Not the case. Pre-facelift Xs were able to direct 100% of torque to front/rear axles and side to side using automatic brake activation.

Originally Posted by PropellerHead (Post 960032)

You may be, but appear not to be aware of how a non XDrive/prefacelift AWD system works:This just isn't true. It should read "Pre-facelift Xs were able to direct power to 38% to the front or 62% to the axles."

I don't have any issue with how this happens- DSC enabled. Never said any different. What I said was that the face lift models with XDrive offer this up to 100%. Pre-face lift X's do not. Plain and simple.

Here is a source from BMW that explains the difference. Pay attention to the 2nd and last paragraphs. The differences in the systems are clearly not what you think they are: