So how do they compare? Is Lexus' predominately frontwheel drive 50/50 or 60/40 rear? Thoughts, opinions? Is it even as good as Acura's sh-AWD?

 

My understanding is that the RX is 50/50 all the time, unless conditions direct the computer to alter that distribution. I don't know how that compares to BMW or Accura, but I doubt that the differences are substantial.

 

Acura's SH-AWD is reactive while the RX's AWD packaging is static 50/50 unless weather condition demands otherwise. No comparison can be made.

 

Out of the 3, I would say the RX is the best in the snow. All 3 are not deasign for off road use. Of course you know the SH-AWD will improve handling.

 

This is interesting:

"Acura's SH-AWD is reactive while the RX's AWD packaging is static 50/50 unless weather condition demands otherwise. No comparison can be made."

If no comparison can be made, what was that?

 

I think he meant that SH-AWD had a different intent-to improve handling for those of us who ever drive at nine-tenths and above. The RX awd system is not intended to be sporty, just to go in mud and snow and keep the average woman who drives an RX out of the worst trouble. Therefore a comparison of which is better makes little sense.

 

The SH-AWD starts to work very early on even at lower speeds. You don't need to be driving and 9/10s for it to work. If you drive normal, it is working every day. I haven't driven the SH-AWD in the MDX or RDX, but have done so on the RL. If you haven't driven an SH-AWD car, you should try it. It is amazing and you don't even have to be going fast. It really does turn a FWD biased car into a RWD neutral handling car.

As for how it works in the snow, reports have show good results and reviews so I suspect it should be just fine in those conditions.

 

The BMW system is far superior with its latest enhancements. Here is an explanation that may answer the question.-------------------

SEE VIDEO LINK AT THE END

In April of 2007 BMW has just taken the wraps off an advanced torque vectoring system that promises to improve both the agility and stability of its four-wheel drive models.

Called Dynamic Performance Control, the new system is an evolution of BMW’s xDrive system, but adds a series of additional electro-magnetic clutches, in a modified rear differential housing that allow power to be juggled between the individual rear wheels as well as between the front and rear axles.

Dynamic Performance Control works in conjunction with sensors in the anti-lock braking system that measure steering angle, yaw rates, road speed and torque developed by the engine. Essentially, it directs drive to where it can be used most effectively in an operation not dissimilar to that of a traditional locking differential on a rear-wheel-drive car.

If the car understeers, xDrive will redirect more drive to the rear wheels and, if required, the Dynamic Performance Control system will then load up the outside rear wheel with the balance of power, providing an additional turning moment beyond that generated by the steering wheels. During oversteer, it reverses the action, sending the majority of drive through the front wheels and, if necessary, increasing torque to the inside rear wheel to stabilise the car during cornering. Both processes are explained in BMW's images, which you'll find in our gallery.

Unlike similar systems developed by rival car makers, BMW’s Dynamic Performance Control operates both under load and on the overrun, meaning the car continues to be stabilised even when the driver steps off the throttle mid-corner.

BMW is tight-lipped on when Dynamic Performance Control, developed in partnership with German engineering specialist ZF, will be introduced. It will probably appear first on the X6 crossover coupe, before heading into other models, including the X3, X5 and four-wheel-drive versions of the 3-, 5- and next-generation 7-series. Also earmarked to accept the new system is BMW’s seven-seat MPV, and a secret new junior four-wheel-drive that’s tipped to slot into the German car maker’s line-up beneath the X3.

So what does it feel like?

In an exclusive test drive at BMW’s newly established winter test centre in Arjeplog, Sweden this week, Autocar was able to evaluate Dynamic Performance Control on a fleet of modified 530iX saloon and touring models.

It's a subtle but worthwhile improvement. By allowing the torque to be distributed in varying degrees to either the left- or right-hand rear wheels, the cars equipped with the new BMW system proved more neutral during cornering than those running the existing four-wheel drive xDrive mechanical package.

Understeer is well suppressed thanks to the ability of Dynamic Performance Control to direct greater torque to the outside rear wheel, and big oversteer moments are quickly dealt with as the inside rear wheel is favoured. The upshot is improved cornering balance, and an ability to delve deeper into the car’s dynamic repertoire, more of the time.

As well as instilling greater confidence in the driver, the new system also reduces the amount of steering input required, which was typically halved as we attacked BMW's winter handling course. For this reason, BMW does not plan to equip models running Dynamic Performance Control with its Active Steering system.

http://content.bmwusa.com/microsite/...IESLANDINGSWF1

 

Sounds like the table has turned, the Germans are now copying the Japanese

 

Hehehe, yes it does kind of sound like what an SH-AWD version 2 might be like.

 

Lol, I find that funny. For years, people have accused the Japanese of copying other people's technology. Now the mighty Germans is doing the same. One thing I give the Japanese credit for is not copying that stupid I-drive system from the Germans. You need a co-pilot to drive a car with that thing.

 

You sure about that?

Was my understanding that the RX AWD is FWD biased, something like 90/10, adjusting as needed.

 

It was me trying to tell the difference between the RX and the MDX's AWD system. Me comparing the two would be "Blah Blah is BETTER than Blah Blah". JayDunn correctly interpreted my intention.

Going back to the original topic, the MDX is like night and day to the RX. The RX is an AWD SUV, while the MDX is an SUV that uses AWD to be a sporty AWD sedan. Different playing field here. Can't compare RX and MDX. you should compare MDX to the X5 though to be fair. But I haven't driven the X5 at all.