Driving the Supercharged A6

It's not easy to get too excited by the 2009 Audi A6. Yes, some 234,000 examples of Audi's executive barge were sold around the world last year, more than either the BMW 5 Series or the Mercedes-Benz E-Class. But while the A6 sets the tone of Audi's styling look, it lacks the luxury chutzpah of the Audi A8 or the sporting finesse of the smaller Audi A4.

This car has always been eminently sensible, and so perhaps it's in keeping with the brand that this face-lift for the 2009 Audi A6 should be subtle. The aesthetic changes are so miniscule that if Audi's stylists were cosmetic surgeons, you'd be asking for your money back.

And yet the thing that has always held back the A6 has been under the hood, as the long-stroke Audi V6 lacks any trace of personality even as it goes about its duties with perfect composure. That's why the introduction of the new 2,995cc TFSI V6 could be really significant. This is a supercharged engine, and it's all about a bid to combine improved power and response with lower fuel consumption.

Back to the Future
The last time this car company dabbled with supercharging, it was known as Auto Union, and Professor Porsche's V12- and V16-powered midengine monsters were fighting Mercedes-Benz in titanic battles for grand prix supremacy during the 1930s.

Now there's the supercharged 2,995cc TFSI V6 for the 2009 Audi A6. (While the "T" should indicate turbocharging, the forced induction is provided by a supercharger, and even Audi is apologetic about this misnomer apparently forced upon it by some bright spark in the marketing department.) And like the Auto Union engines of the 1930s, it's actually meant to provide a wide, docile power band, not peak power.

Like the latest-generation superchargers we've seen lately, this compact Roots-type blower nestles inside the 90-degree Vee between the V6's cylinder banks, taking the place of the intake manifold. Two contra-rotating, four-vane shafts turn at up to 23,000 rpm, delivering maximum boost of 11.5 psi. Twin water-to-air intercoolers help improve charge density.

Audi's direct injection technology has been applied here, and a common-rail unit sends fuel into the combustion chambers at as much as 2,200 psi. The direct injection system also has packaging advantages, enabling the supercharger to be located behind the throttle in an area of low-density air. As a result, the supercharger is less of a mechanical drag on the engine. Plus the throttle response is good, because the location of the supercharger between the cylinder banks offers very short intake tracts.

The net result of all this technical trickery is an engine that delivers 286 horsepower from 4,850 rpm to 6,800 rpm, not to mention 310 pound-feet of torque from 2,500-4,850 rpm. Audi says the revised A6 will accelerate to 100 km/h (62 mph) in 5.9 seconds and then on to an electronically limited top speed of 155 mph.

Measured Against the Competition
The supercharged V6's power figures bear comparison with the 4.2-liter Audi V8, which musters 350 hp and 325 lb-ft of torque. The acceleration times of the V6- and V8-powered cars to 100 km/h are identical, yet the V8 uses substantially more fuel on the European driving cycle — 23.1 mpg for the V8 versus 25 mpg for the supercharged V6.

The new supercharged V6 also trounces the Mercedes-Benz E350's 3.5-liter V6 with its 268 hp and 258 lb-ft of torque, and can stand toe-to-toe with the BMW 535i's twin-turbo 3.0-liter inline-6 with its 300 hp and 300 lb-ft of torque.

The V6 even sounds good. The deep bass rumble of the V8 might be missing, but it's been replaced by a baritone voice of considerable clarity. Audi has clearly spent a lot of time tuning the exhaust and induction noises while dialing out the sound of the supercharger. Listen hard and you can make out a subtle whine, but it's hardly intrusive.

Meanwhile, Audi's six-speed automatic is standard with this engine and it proves an ideal foil. It's been tweaked slightly and it disengages the torque convertor at a standstill in a bid to reduce fuel consumption. It automatically reengages when you lift off the brakes. It's a slick companion and it's good to see shift paddles fitted as standard equipment, because if Audi is serious about building sport sedans, then such details matter.

Driving While German
The A6 has always been a big car. At 194.4 inches in overall length, it's 3.3 inches longer than a 5 Series and 3.2 inches longer than an E-Class, largely a consequence of its all-wheel-drive powertrain. And at 79.9 inches across the beam, this is also a wide car. You're always conscious of the 2009 Audi A6's bulk; this is not a car that seems to shrink around you like a Jaguar XF.

The Quattro four-wheel-drive system has been reworked in tune with the rest of the Audi range so that 60 percent of the available torque is now sent to the rear wheels and 40 percent to the front. In theory, this should alter the handling characteristics to make the A6 feel more like a rear-wheel-drive car, but in practice the difference is miniscule. The A6 is still a car that responds best to measured, precise and subtle inputs, a trait not helped by steering that still feels disappointingly vague.

Audi's engineers have also been to work on the A6's suspension in a bid to improve its much-criticized ride quality, and larger-volume front dampers help offer improved action with more precise control. Meanwhile, every test car at our disposal had been fitted with the optional air suspension, which offers Comfort, Dynamic and Automatic settings. Dynamic is downright harsh, while even Comfort fails to offer the bump absorption of an E-Class or XF. In our view, calling a car a "sport sedan" is no excuse for an overly firm ride.

The Audi Look
You'll need to be a dedicated Audi spotter to tell the difference between the old A6 and the new. There are changes to the grille, foglights and air intakes at the front, but you'd be hard-pressed to notice. The only obvious change is the introduction of six LED daytime driving lights in each headlight, an optional feature.

At the rear, the changes are more significant. You get distinctive, angular LED-type rear lamps, a more pronounced spoiler on the trunk and an aero diffuser beneath the bumper. The latter, one suspects, has more to do with the need to look different than significantly improved aerodynamic efficiency.

Within the cabin, you'll find some new materials, a bit more chrome and a reworked Multi Media Interface (MMI) that still sets the standard for these automotive joysticks, although it's now becoming a bit too complicated as more features are added.

The 2009 Audi A6 remains a very spacious, comfortable car that's beautifully built, but it can also seem somewhat stark and uninviting depending on the way it's equipped. There are too many blank buttons for a car in this price range and it lacks the cozy, accommodating feel of the Jaguar.

Updated but Maybe Not Improved
Let's get to the point. The new engine is a treat that should soon be successfully employed in the rest of the Audi range. (An Audi TT with this engine would be something to behold.)

The new motor is certainly well employed in the 2009 Audi A6. Audi's executive transport remains a finely crafted machine that scores highly for space and quality. The face-lift plays to the A6's strengths, but it fails to significantly address its key failings — namely an overly firm ride and a cabin that's still not as enticing as a car at this price level needs to be.

The 2009 Audi A6 continues to be exactly the right sort of package for the U.S.: spacious, easy to drive and sure-footed in every kind of weather. And yet just 12,000 examples hit the road in America last year. Clearly this car lacks some kind of magic, and we're not sure it's found it with this makeover.