We've seen dramatically good mileage in diesel cars, such as the BMW 335d and the Volkswagen Jetta TDI, but the 2009 Volkswagen Touareg TDI doesn't meet the possibly unrealistic expectations given to us by these other cars. This SUV shows diesel's ridiculously high torque, while delivering the kind of acceleration and general drivability we've come to expect from gasoline-powered cars. But we wanted to see fuel economy in at least the high 20s.
Besides the diesel engine, the Volkwagen Touareg TDI is the same as its gasoline-powered siblings. The cabin incorporates a luxury that puts the Touareg almost into Audi territory. This Touareg TDI also came equipped with Volkswagen's new navigation system, a hard-drive-based unit we first saw in the Volkswagen CC sedan. Unfortunately, the more time we spent with this navigation system, the more we grew to hate it. For other cabin tech, the Touareg TDI gets a special audio port that can interface with iPods, other MP3 players, and USB drives, very similar to the Audi Music Interface.
The Touareg TDI that arrived in our garage came equipped with the navigation system and iPod integration, but lacked other available tech features. Volkswagen offers a Bluetooth phone system option, although that's a feature we think should be standard on all cars by now. There is also an interesting array of driver aid equipment, including adaptive cruise control and blind-spot detection. For off-roading, the Touareg TDI can also be had with an adjustable air suspension. Its standard equipment includes all-wheel-drive with low range and locking controls for the differentials.
Equipped with the standard suspension, our car sat moderately high with 8.3 inches of ground clearance. Its curved body lines give it a European look, unlike the boxy, truck-like SUVs from U.S. automakers. The white paint was only marred by a green D sticker on the fuel filler lid, a reminder not to put gasoline in the tank. On the back of the car, Volkswagen colored the I in the TDI logo blue, designating the AdBlue emissions clean-up technology, which uses urea to break up nitrogen oxide from the engine into nitrogen and oxygen. The urea tank needs to be refilled every 6,000 to 10,000 miles.
From the driver's seat, a redline of 4,300rpm on the tachometer also gives a clue that the Touareg TDI is a diesel. But you wouldn't know it from the sound of the engine. The well-insulated cabin of the Touareg TDI keeps the clatter of the diesel engine to a minimum. For slow to moderate starts, the car feels eager to move, showing no turbo lag or diesel hesitation. Although the turbocharged 3-liter diesel engine only makes 221 horsepower, its 406 pound-feet of torque gets all four wheels turning quickly. At 8.5 seconds to 60 mph, the Touareg TDI is no speed demon, but it will keep up with most cars on the road.
Around town, the Touareg TDI proved very drivable, maneuverable enough to negotiate obstacles, and parking assisted by sonar and a rear-view camera. Trying out a few sprints, the car starts off with leisurely acceleration, but the big torque figure means the power doesn't diminish at higher speeds. That attribute of diesel pays off on the freeway, too, where the Touareg TDI performs passing maneuvers at 65 or 70 mph with ease.
But we also noticed that the tachometer sticks around 2,000rpm at freeway speeds, about halfway to redline. A better overdrive gear from the six-speed automatic could lower the engine speed, but will probably result in a sacrifice of power. The weight of the Touareg and this high engine speed while cruising lessens the car's fuel economy. The EPA rates it at 17 mpg city and 25 mpg highway. During our week with the car we averaged 20.6 mpg. That's a big jump from the 13.4 mpg we averaged with a gasoline-powered V-8 Touareg, but our experiences in diesel cars have given us unrealistic expectations for SUV diesels.
The Touareg TDI's six-speed automatic has sport and manual modes along with the standard drive mode. In an SUV of this bulk, we weren't inclined to use sport or manual mode much beyond our typical testing. This car isn't made for cornering, its high center of gravity contributing to plenty of lean when the inertial forces start pulling it to the side. The standard suspension is designed for comfort, not sport, although the optional air suspension will hunker down an extra inch as speed increases.
Besides the fuel economy, we also had high expectations for the navigation system, as Volkswagen's previous system is dismal. But right from the moment we tried programming in some destinations, we found the system strangely slow to respond. Usually, a hard-drive-based navigation system means fast response times, but Volkswagen must have cheapened out on the processor. The system's touch-screen interface proved easy to use, with an onscreen keyboard allowing direct input for destinations. However, entering destinations using the map was made frustrating by the slow processor, as the map cursor moves too slowly.