Just when we thought BMW’s “Sports Activity Coupe” couldn’t make any less sense, BMW announces official details on the 2010 ActiveHybrid X6, proudly proclaiming it “the most powerful hybrid vehicle in the world.” Um, okay? Seems a bit like striving to be the most foul-mouthed nun in the world—it’s not really the point.

But if we’ve come to expect anything from the weird, off-road, four-door coupe/sports car, it’s that we won’t understand it but we will appreciate it. And, truth be told, there appears to be much to appreciate about the upcoming hybrid X6. It’s powered by the 400-hp, 450-lb-ft twin-turbo V-8 from the (relatively) normal X6 xDrive50i, supplemented with two electric motors: the first makes 91 hp and 192 lb-ft of torque and the second produces 86 hp and 206 lb-ft. If calling it the “ActiveHybrid” seems contrived, consider that, compared to the X6 hybrid’s combined system power of 480 hp and 575 lb-ft of torque, most other hybrids will indeed seem sedentary. In addition to a 20-percent increase in fuel economy in the European cycle, BMW claims a 0–60 time of 5.4 seconds. That’s just one tenth behind the company’s 5.3-second claim for the nonhybrid V-8 X6 (although we’ve clocked that version to 60 in just 5.1 seconds). That the more powerful hybrid is slower is likely due to the significant weight of the hybrid equipment. Top speed is governed at a very environmentally unfriendly 130 mph.

One of These Things is Not Like the Other

This X6 and also-just-announced BMW ActiveHybrid 7 share the honor of being BMW’s first-ever hybrids, but they share little else. Although both boast componentry co-developed with competitors—and share the 4.4-liter twin-turbo V-8—the systems are dramatically different. The 7 uses a mild hybrid system created with Daimler and utilizing just one electric motor. The X6, on the other hand, boasts two electric motors and is a full hybrid capable of operating on electric power alone up to 37 mph or for 1.6 miles. (We would guess people interested in “the most powerful hybrid vehicle in the world” aren’t going to be the type to featherfoot their BMW to maintain electric-only propulsion.)

The X6 hybrid gets its hybrid capabilities from a two-mode hybrid transmission co-developed with General Motors and Daimler. The same transmission is used in the Chevrolet Tahoe, GMC Yukon, and Cadillac Escalade hybrids, as well as the short-lived Dodge Durango and Chrysler Aspen hybrids. (It will also appear in the upcoming Mercedes-Benz ML450 hybrid.) It combines an electronically controlled, continuously variable transmission and a conventional automatic to optimize fuel efficiency around town without sacrificing highway fuel economy.

The high internal friction of CVTs means that, although they provide infinite flexibility and can hold the engine at its most efficient (or powerful) speed for a given situation, their highway fuel-economy benefit is minimal. A conventional automatic, on the other hand, takes less energy to spin, and accordingly uses less gas on the highway. While it still sounds strange to use “BMW,” “Chrysler,” “GM,” “Mercedes” and “co-develop” in the same sentence, the transmission works quite well in the GM hybrids, and we admit a small sense of pride in the home team for its role in the project. Of course, since this is a BMW, X6 hybrid drivers will be able to manually shift among seven pre-programmed gear ratios. Stuff wearing a roundel has to be more complicated, right?

Few Visual Clues

A 2.4-kWh nickel-metal hydride battery—as opposed to the ActiveHybrid 7’s compact lithium-ion unit—hides under the floor in the cargo area in the space usually reserved for a spare tire (the ActiveHybrid X6 wears run-flat rubber to compensate), and a dedicated cooling system utilizes both outside air and the air-conditioning system to keep the battery comfy. The usual, ahem, battery of hybrid equipment includes regenerative braking, variable electronic steering, and automatic start/stop functionality for the engine.

Externally, the hybrid is differentiated from other X6s by a domed hood à la M3 and “ActiveHybrid” badging on the doors that is strangely smaller than the usual “xDrive50i” banners. Unique 20-inch wheels are standard (and said to have an aerodynamic design), and 19s with all-season tires will be optional.

The world’s most powerful hybrid vehicle will debut at the Frankfurt auto show in September, and U.S. sales will commence late in 2009. BMW isn’t talking pricing yet, but with a V-8 X6 starting above $67,000 and the also recently announced X6 M basing at almost $90,000, we’d put the ActiveHybrid X6’s base price right around $80,000. As Sister Mary Harriet once said about the Vatican’s art collection, that shit ain’t cheap.

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