2002 Audi A6; Continuously better.(Statistical Data Included)(Evaluation)

While the Audi A6 line has been updated with new front and rear fascias for the 2002 model year, the biggest change in what Audi North America's marketing chief Marc Trahan described as the marque's ``center of gravity'' is beneath the hood. The present-generation A6, introduced in the fall of '97 as a '98 model, will be available this fall with a new 3.0-liter V6 engine and an in-house-developed continuously variable transmission, dubbed multitronic.

The 3.0-liter engine, developing 220 hp at 6300 rpm and 221 lb-ft at 3200 rpm, is a result of the VW Group's purchase of Cosworth Engineering. Cosworth's rollover-casting technology was used in producing the aluminum block that is 44 pounds lighter than a similar-sized cast-iron block and 26.5 pounds lighter than the 2.8-liter engine it replaces in the Audi lineup. The new powerplant is also available in the A4 (AW, Cover Story, July 30).

The five-valves-per-cylinder engine features variable camshafts and a two-stage variable intake manifold. While the peak torque of the engine is at 3200 rpm, 90 percent of the torque is available from 2200 rpm all the way up to 5200 rpm.

The new A6 will also be available in the United States with the current two upgrade powerplants, a 250-hp, twin-turbo 2.7-liter V6 and a 300-hp 4.2-liter V8.

The 3.0-liter engine is silky smooth and has been tuned for a pleasant exhaust note. It's an improvement over the 2.8-liter engine it replaces, especially in regard to its strong torque curve. But the multitronic transmission will have people reassessing their views of continuously variable transmissions.

The multitronic transmission (that's with a lowercase ``m,'' like the lowercase ``q'' in the company's popular quattro) has been available in Europe for more than a year, but makes its U.S. debut in the 3.0-liter Audi A6 and A4. Continuously variable transmissions are more efficient than standard automatic transmissions, but have been limited in their use due to the amount of torque they have been able to control. Audi's multitronic can handle the 221 lb-ft of the 3.0-liter engine, but that number is at the upper limits of its ability. To handle more torque would require a physically bigger transmission, and the subsequent gains in efficiency would be lost.

Transmissions, whether manual or geared automatics, normally have specific transmission stages inside the transmission casing. These stages are in the form of four, five or six or more gears or planetary gear trains. On a CVT, there is just one pair of gears with a flexible transmission belt (in the case of the multitronic, it's a flexible chain) that permits an infinite number of transmission ratios. The gear changes-though they're not really gear changes as we know them-are done seamlessly.