Ingolstadt, Germany – For its mid-cycle freshening, the had its face lifted, its suspension stiffened slightly, its power steering reworked for a bit more effort, its standard equipment bolstered (with a six-disc in-dash CD player, side curtain air bags, brake assist, stability control), and, most interestingly, its base powertrain replaced with one that’s both new and novel.
The 2.8-liter V-6 in the base A6 (and also in the new A4) has been replaced by a 3.0-liter V-6. The 3.0-liter also uses a 90-degree V angle and five valves per cylinder but is otherwise all new. Unlike the outgoing engine, it is all aluminum and employs a balance shaft for smoothness. Its 220 hp and 221 lb-ft of torque wouldn’t seem to be a great leap over the 2.8-liter’s 200 hp and 207 lb-ft, but with its broader torque curve the A6 3.0 has a liveliness that the A6 2.8 did not.
The new engine must share credit for the increased spunk with what is technically the most interesting aspect of the revised A6: its continuously variable transmission. This Audi-developed unit, called Multitronic, uses a steel chain operating in tension between a pair of two-piece, variable-diameter pulleys. The new chain concept allows this CVT to handle more torque (up to 221 lb-ft) compared with previous CVTs which used drive belts operating in compression. Audi’s Multitronic is also interesting in that it’s designed to mimic some of the characteristics of a conventional automatic. When in drive, the Multitronic provides some forward “creep,” although not when you have your foot on the brake. Under acceleration, engine speed does not stay constant but climbs as with a conventional transmission–except under full throttle, when it will reach and hold a set rpm to provide maximal acceleration. Also, the Multitronic will select a lower or higher ratio (six have been programmed) in response to input from the Tiptronic-style gearshift. Multitronic also uses computer mapping to adapt to individual driving styles and can use engine braking to help the cruise control hold a preset speed down hills. All this happens so seamlessly that most drivers might never suspect they were driving anything other than a conventional automatic. The only difference is that the Multitronic’s changes in ratio are so smooth as to be imperceptible. Furthermore, Audi claims the CVT should get better fuel economy than a five-speed manual. That’s at least partly because while the Multitronic’s lowest ratio is nearly the same as a five-speed manual’s first gear, its tallest is much higher than a manual’s fifth.
For now, the Multitronic replaces the Tiptronic manu-matic gearbox only in the front-wheel-drive versions of the A6 3.0, the A4 3.0, and the A4 1.8T. Audi is working to engineer Multitronic for Quattro all-wheel-drive applications but isn’t likely to have it ready until 2004.