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Expect More Magic-Handling Cars if German Supplier Has Its Say
LAURENS, South Carolina — BMW's new X6 may not be the most useful "packaging" job on the road, but word's getting around quickly about insane handling of BMW's gnarly crossover "coupe:" The 5,000-pound X6 can practically outcorner a 911, and Inside Line's own testing shows the blunderbuss slithers through the slalom quicker than BMW's 550i sedan. And if the supplier responsible for some of the hardware that helps the X6 work these wonders has its way, the technology will be showing up on a lot more cars in the near future.
Although BMW's chassis-development experts clearly tuned the daylights out of the X6, much of the credit goes to the X6's suite of high-tech chassis and driveline components manufactured by German mega-supplier ZF, which makes the X6's most important new handling-influencing component, the excellent Dynamic Performance Control rear axle. The DPC differential can actively apportion drive torque sent to the rear axle between either of the rear wheels. The net result is that when cornering, more torque is directed to the outside rear wheel — effectively "rotating" the X6 into the corner, reducing the understeer that typically chokes the cornering hijinks in almost every vehicle.
BMW and ZF engineers say the remarkable new DPC (ZF calls it Vector Drive) rear diff also allows you to go faster by reducing the degree to which stability control cuts in to keep you safe. Stability control (BMW acronym: DSC) works by using the brakes to keep the vehicle on the intended path if you're too "hot" in a corner — but as we all know, the brakes slow you down, so DPC's ministrations mean e.t.a.-killing DSC (got those acronyms straight?) frequently can remain in the background.
We mentioned a "suite" of chassis-control components, and for the X6, that includes the ZF-made Adaptive Drive, which incorporates electronically valved adjustable dampers and active antiroll bars at the front and rear to all but eliminate body roll in corners. It is the almost total lack of body roll — combined with that corner-carving torque-vectoring DPC rear differential — that endows the X6 with its freakish handling abilities.
But ZF doesn't want the X6 to be the only vehicle fronting these technologies — it would like to spread its chassis delights throughout the automotive cosmos. At tiremaker Michelin's proving grounds here, ZF cut us loose in a development car — a BMW 5 Series wagon — with the entire gamut of the X6's electromechanical handling enhancers, including the Active Steering system that is optional for the X6. And just like the X6, ZF's "Intelligent Wheel Dynamics" test car just keeps turning and turning, while the body stays pool-table flat, even at stupid speeds.
All this stuff ain't cheap, of course (that DPC rear axle alone looks like it costs about the same as a midsize Kia), which means ZF's chassis-magic components probably will remain in the premium-car sector for a while. But as with most automotive technologies, time and higher production volumes will drive the technology into lower-priced vehicles.
What this means to you: Everyone should get the chance to toss around BMW's X6 just to experience what's possible with today's best chassis-control technology. We can only wait for the day this kind of handling ability is as common and affordable as an automatic transmission. — Bill Visnic, senior editor, Edmunds AutoObserver
Although BMW's chassis-development experts clearly tuned the daylights out of the X6, much of the credit goes to the X6's suite of high-tech chassis and driveline components manufactured by German mega-supplier ZF, which makes the X6's most important new handling-influencing component, the excellent Dynamic Performance Control rear axle. The DPC differential can actively apportion drive torque sent to the rear axle between either of the rear wheels. The net result is that when cornering, more torque is directed to the outside rear wheel — effectively "rotating" the X6 into the corner, reducing the understeer that typically chokes the cornering hijinks in almost every vehicle.
BMW and ZF engineers say the remarkable new DPC (ZF calls it Vector Drive) rear diff also allows you to go faster by reducing the degree to which stability control cuts in to keep you safe. Stability control (BMW acronym: DSC) works by using the brakes to keep the vehicle on the intended path if you're too "hot" in a corner — but as we all know, the brakes slow you down, so DPC's ministrations mean e.t.a.-killing DSC (got those acronyms straight?) frequently can remain in the background.
We mentioned a "suite" of chassis-control components, and for the X6, that includes the ZF-made Adaptive Drive, which incorporates electronically valved adjustable dampers and active antiroll bars at the front and rear to all but eliminate body roll in corners. It is the almost total lack of body roll — combined with that corner-carving torque-vectoring DPC rear differential — that endows the X6 with its freakish handling abilities.
But ZF doesn't want the X6 to be the only vehicle fronting these technologies — it would like to spread its chassis delights throughout the automotive cosmos. At tiremaker Michelin's proving grounds here, ZF cut us loose in a development car — a BMW 5 Series wagon — with the entire gamut of the X6's electromechanical handling enhancers, including the Active Steering system that is optional for the X6. And just like the X6, ZF's "Intelligent Wheel Dynamics" test car just keeps turning and turning, while the body stays pool-table flat, even at stupid speeds.
All this stuff ain't cheap, of course (that DPC rear axle alone looks like it costs about the same as a midsize Kia), which means ZF's chassis-magic components probably will remain in the premium-car sector for a while. But as with most automotive technologies, time and higher production volumes will drive the technology into lower-priced vehicles.
What this means to you: Everyone should get the chance to toss around BMW's X6 just to experience what's possible with today's best chassis-control technology. We can only wait for the day this kind of handling ability is as common and affordable as an automatic transmission. — Bill Visnic, senior editor, Edmunds AutoObserver
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