Last week I got the chance to spend plenty of time in Audi’s diesel Q7, both behind the wheel and in the passenger seat. By plenty of time I mean somewhere in the order of 10 hours a day for three days. Across two time zones and three states I slogged mile after mile in the big-daddy SUV, stopping only for photos and fuel. That amount of time serves up all of a vehicle’s quirks as well as its attributes, and over all I’ve got to say I liked what I saw and felt. With plenty of grunt, unbelievable fuel economy and room for seven inside, this rig is almost enough to make me give into the waning SUV craze. Jump for more of my thoughts.

Engine and Drivetrain
This is where the Q7 3.0 TDI differs from its petrol brethren. Our model gets to speed thanks to a 3.0-liter turbo-diesel V6 engine that puts out 225 horsepower — just 55 less than the gasoline version — and 405 lb-ft of torque. That last number is a full 139 lb-ft more than the 3.6-liter gasoline engine at 266 lb-ft, and you can feel it in your chest once the turbo gets going.

Speaking of the turbo, my only real gripe with the engine is the small amount of turbo lag that comes with the TDI. Mash the throttle during panic traffic maneuvers and power just isn’t instantaneous. Of course, that’s just about the only time you notice the diesel mill up front at all. During normal motoring the power plant sings happily along. Noise is on par with the gasoline engine and the putrid cloud of black smoke we Americans tend to associate with diesels is gone forever.

Green Machine
The 2009 Q7 3.0 TDI earns big time marks in the green category thanks not only to its superb fuel economy when compared to the gasoline version, but also thanks to Audi’s innovations on the emissions front. According to Audi, the oil-burning Q7 gets 17 mpg city and 24 mpg highway while the petrol 3.6-liter gasoline version manages 14 mpg city and 20 mpg highway. That’s all fine and dandy, but we found that during normal driving, the diesel could happily crank out an average 27 or 28 mpg, and that’s phenomenal.

Diesels have long had to deal with the emissions stumbling block here in the states. That’s due largely to the heavy amount of nitrous oxides the fuel emits when burned compressed. Audi has countered this obstacle with the Mercedes BlueTec method — a urea compound into the catalytic converter. The urine-based compound encounters the nitrous oxides and along with the heat from the exhaust gasses combines to form just ammonia and water. According to Audi, the system has reduced diesel emissions by 95 percent.

Pages: 1 2