For perspective, that acceleration puts the D3 diesel soundly in H3 territory and a fraction to one second slower than an Escape V-6, Liberty CRD, H2, and Prius. None of those weighs 5500 pounds and none carries seven people; we're not convinced they can all do 112 mph, either, and shorter gearing would likely make a TDV6 brisker with next to no penalty in fuel economy.
At a steady 65 mph, the TDV6 computer displayed an average fuel use of 29.8 mpg, and despite our repeated top-speed verification, acceleration runs, generally driving exactly the opposite you should in a three-ton 4WD, and less-then-ideal conditions, typically in 30-degree wet weather, fully loaded, we still averaged more than 20 mpg. In city stop-and-go or less aggressive use, we'd expect close to 25 overall.
The Ultimate Diesel Machine?
One might argue that BMW knows as much about diesels as Mercedes, having brought one to the U.S. market, offering them in every sedan (even the long-wheelbase 7 Series), and entering a twin-turbo diesel in the Paris-Dakar rally.
BMW makes more than one 3.0-liter turbodiesel and multiple ratings. This second-generation unit has an aluminum block and head with a single turbo, EGR, and diesel catalyst. Ratings are about 214 U.S. horsepower at 4000 rpm and 368 pound-feet of torque from 2000 through 2750 rpm, again comparable torque at lower rpm than the 4.4-liter gasoline V-8 choice.
A handheld stopwatch recorded 0-to-62 mph in 8.74 seconds while the trip computer's stopwatch gave us the same 8.8 that BMW quotes for the automatic. This is about one second slower than an X5 3.0 gas engine we tested in 2002, but that X5 benefited from a manual gearbox (with 5.09:1 first and direct-drive fifth) and 4.10:1 gears; the diesel tested had 3.91:1 gears that, like the D3, might sensibly be swapped for something a bit shorter for the North American market. Top speed is given as 210 kph (close to 130 mph), an indication that proved easy to reach unless the snow dictated slowing down. A certain amusement comes from driving at top speed with a trip computer showing mileage in the teens, whether or not it's precise.
BMW's gas 3.0-liter carries EPA ratings of 15/21, and we were able to record 19.8 on one highway cruise. The 3.0-liter diesel, routinely tested in city traffic or close to its top speed, roughly twice as fast as the gas tester, averaged better than 21 mpg. Official figures give the diesel a 50-percent economy advantage in the urban cycle and a smaller gain in the city; CO2 values are similarly lower.