To M purists, the BMW X6 M50d is an anathema. The vehicle breaks the all three of the sacred M laws: it's not gas-powered, it's not rear-drive, and it doesn't exhibit scalpel-like handling.
Before we send this not-for-the-U.S., diesel-powered beast to purgatory, let's give the all-wheel drive X6 M50d a chance to represent. After all, over the past couple of years, BMW's M crew has rolled out a slew of twin-turbocharged M cars. And although the M6, and the other M-badged X6, the X6 M (confused yet?) handle more like a chainsaw, they all are very good cars. Change is inevitable, and like Benz's AMG division, the M stamp is showing up on everything that moves in the BMW stable. Is it a good thing? BMW sure thinks so.
The X6 M50d isn't even a full-on M car. Instead, it's a product of BMW's new M Performance division, along with the M50d, M550d, and M135i -- high-performance models with a slightly softer edge. So the plan is keep making the hardcore M models, and offer other not-so-hardcore M models. Check. Now that that's all cleared up, let's see what this car is all about.
There's something unique under the hood of the M50d, namely three turbos stuffing air into the cylinders. The engine is an evolution of BMW's twin-turbo, 3.0-liter, straight-six diesel fitted to several models in the automaker's range. The tri-boosted six produces 381 horsepower and a brawny 545 lb-ft of torque, and helps the 2-and-a-half ton monster run to a low-5-second 0-60 mph time -- on par with boatload of lighter, more nimble sports cars, and yes, the X6 M.
The thinking behind three turbos is to simultaneously reduce lag and improve throttle response, while broadening the power band and strengthening the top end. At low revs, a small high-pressure turbo spins up quickly, reacting almost instantly to your right foot. At 1500 rpm, it's supported by a large, low-pressure turbo. The final small high-pressure turbo joins in between 2600 rpm and 5400 rpm and keeps the engine humming all the way to redline.
As a consequence, this is a diesel engine that loves to rev. Do so and you're treated to a sweet-sounding warble from the exhausts and a relentless shove in the back. The only thing I can compare it to is the Audi Q7 V12 TDI, a 12-cylinder, diesel-powered oddity that pulled so hard and gobbled up its narrow power band so quickly that the gearbox spent more time swapping cogs than it did sending power to the wheels. Here that's not a problem, as BMW's superb eight-speed auto is as fast as it is smooth, and that extended sweet spot allows you to hold each ratio a little bit longer.
BMW's adaptive air suspension, self-leveling at the rear, comes standard, and is augmented by M-specific firmer springs and electronically controlled dampers. While the X6 rides with classic BMW balance in its softest setting, when you crank up the dampers, the bumps in the road will send thuds through the chassis and up your spine. The payoff in the sportiest chassis settings is otherworldly body control for a vehicle so big and heavy and a center of gravity so far from the tarmac. Drive quickly down a narrow, twisting road, and you soon find yourself forgetting the X6's size and flinging it around like a sports car -- within reason, of course.
If you like being noticed, you'll like driving this car. The standard X6 is hardly a shrinking violet, but the M50d goes even further to elevate the hulking SUV coupe above the pack. A hood bulge; 20-inch, V-spoke rims; and the hallowed M badge on the rear lightly inflate the exterior, while the inside is cluster-bombed with M badges.
The X6 M50d is a brute of a car that in isolation is a fantastic place to spend time and is wonderful to drive, either slowly or at full tilt. It also cements BMW's position at the top of the engineering tree. (As BMW releases this tri-turbo diesel engine across Europe, Audi is simultaneously launching a bi-turbo unit.) But whether people will buy it is another matter.
The trouble is, for all its on-paper clout and clever branding, the X6 40d with the garden-variety 3.0-liter twin-turbo diesel is some $20,000 cheaper, almost as fast, and delivers similar sensations on the road. That means that while it's quick and more desirable, the X6 M50d is largely about bragging rights. But it's not a true M car. Close enough for some, maybe. In any event, U.S. customers won't have to worry about choosing between this and the X6 M, with its measly 4.4-liter, twin-turbo V-8 packing 555 horsepower.
| BMW X6 350d Euro Spec |
| BASE PRICE | $97,000 (MT est) |
| VEHICLE LAYOUT | Front-engine, AWD, 4-pass, 5-door, SUV |
| ENGINE | 3.0L/381hp, 545 lb-ft six-cylinder tri-turbodiesel |
| TRANSMISSION | 8-speed automatic |
| CURB WEIGHT | 4905 lb (mfr. est) |
| WHEELBASE | 115.5 in |
| LENGTH X WIDTH X HEIGHT | 192.0 x 78.1 x 66.5 in |
| 0-60 MPH | 5.2 sec (mfr. est) |
| FUEL ECON | N/A |
| CO2 EMISSIONS | N/A |
| ON SALE IN U.S. | No |