New A6: lighter, leaner but with room to move

Audi has turned the tables on the trend to automotive obesity, using aluminium to make its new generation A6 at least 80kg lighter than the outgoing machine. And while it has resisted a push for radically new styling for the A6 sedan, the world's fastest growing prestige brand has also made the new car shorter, lower and far more economical than the series it replaces.

Due to be launched early next year, the new A6 range's eco-cred will be headlined by a 2.0-litre turbodiesel with an emissions figure of 129 grams of CO2/km and just 4.9 litres/100km on the combined consumption cycle.

At 1575kg, the much-revised baby diesel is the family's featherweight. With both a manual transmission and front-wheel drive, it's primarily targeted to Europe's fleet markets. There are four other engine options, though (each of which will hit 100km/h in under 7.7 seconds) but Audi will wait until 2012 before it launches a hybrid version, using a variant of the Volkswagen Audi Group's 2.0-litre TFSI turbocharged petrol four-cylinder engine.

As with the A7 Sportback, Audi has declined to offer a V8 within the standard A6 range. That engine will arrive with the RS version in two years time.

Instead, Audi will offer the 2.0-litre TDI, two versions of the 3.0-litre TDI and two petrol V6s: a direct-injection 2.8-litre and the range-topping 3.0-litre supercharged, direct-injection V6.

The 220kW, 3.0-litre TFSI, which will haul the four-door from 0-100km/h in 5.5 seconds and a limited top speed of 250km/h. It is considerably heavier than the 2.0-litre TDI, however, with all-wheel drive and the seven-speed, double-clutch gearbox bulking it up to 1740kg.

For all that, and its 440Nm of torque, it still revs to 6500rpm yet uses 13 per cent less fuel than its predecessor, even though it has 7kW more power.

It's a story repeated across the board, with the improvements ranging from the 2.8-litre petrol car's 12 per cent economy improvement to the base 3.0-litre TDI's 19 per cent saving.

It's more than just engines, too, with Audi developing a new Efficiency program to join Normal, Comfort, Automatic and Dynamic modes in the computer-controlled Audi Drive Select equipped models.

This system has a software map specifically set up to give the best possible economy, altering everything from the engine mapping to the gearshift points, the steering, the cruise control and it even lowers the ride height to reduce the aerodynamic drag.

For all its oomph, the 220kW TFSI doesn't look like the best all-rounder on the A6 books. That title could well go to the more-powerful of the 3.0-litre TDI twins. The oiler's 180kW might be the headline number, but the key to its performance is 500Nm from just 1400rpm, which should mean it will punch hard any time you push the accelerator pedal.

The 'big' turbodiesel is only a fraction slower than the best petrol engine in the sprints, too, posting a 6.1 second 0-100km/h time and sharing the same 250km/h top speed.

Yet, where the biggest petrol motor uses 8.2L/100km on the combined cycle and weighs 1740kg, the more-powerful 3.0-litre TDI uses just 6.0L/100km, weighs 1720kg and has a combined emission figure of only 158 grams compared to 190.

Both the petrol and diesel rangetoppers use similar double-clutch gearboxes and all-wheel drive. The less-powerful 3.0-litre TDI and the 2.8-litre FSI petrol motor will use Multitronic (constantly variable transmission) gearboxes and front-drive.

While the new A6's profile looks disturbingly like this year's A8 limousine, Audi insists it shares its underbody architecture with the A7 luxury hatchback, so it can come with either conventional or adjustable air springs in its suspension system.

That also means about 20 per cent of its under-skin materials are aluminium. The lightweight metal is also used for the bonnet, front wings, boot lid and all four doors.

Yet, while it's 12mm shorter than the old A6, cabin space has increased markedly. New architecture means its engines can now sit further back in the engine bay, so it has slashed 82mm from the front overhang and pumped the wheelbase out by a significant 69mm to 2912mm. Much of the increase has been translated into rear-seat legroom.

There's also more shoulder room in both rows and the luggage area is, typically, ridiculously large. There's 530 litres of very useful luggage space, with a flat floor, and that bumps out to 995 litres when the rear seats are folded flat (though some of it disappears with the massive bass box the optional Bang and Olufsen sound system uses).

With plenty of extra space in the rear, the A6 gives the rear passengers not only more foot space beneath the front seats, but (in response to US requests) also provides two DC charging sockets for everything from laptops to computer games.

Up front, there's a wonderfully three-dimensional feel to its dash layout that just can't be replicated with LCD screens, as the two major instruments just forward from the central digital display.

The overall theme and button layout will be familiar to anybody who's ever driven an Audi, but it's been refined and tidied up here and there, and it also carries over the A7's wrap-around line at the front-edge of the dash.

The A6 will trump BMW's new 5-Series for storage space, especially with a combination of door pockets that comfortably carry 1.5-litre water bottles, two cupholders in the console and an enormous, covered oddments hole where the optional ashtray would normally be. Unusually, too, the glovebox is larger than the one in the old car.

The car is also a rolling wireless hotspot and you can order your new A6 with a small MMI screen or large one. Audi has intentionally shied away from split-screen technology that allows the passenger to watch TV on the run, for fears that dumb drivers (guess where from?) might be tempted to lean across to watch, then crash, then sue Audi. They should be looking at the optional head-up display!

The new A6 is the third car to use Audi's new grille design (after the A7 and the A8). The wider graphic and headlights combine to give a greater impression of width in a rear-view mirror. Yet, the headlights aren't exactly how the designers wanted them to be, because Audi's had to compromise their shape to accommodate halogen, bi-Xenon and full LED lighting systems.

It's a complicated setup, with halogen lights dictated by the lower-end of the range that sees the base car line up at €38,500 ($A52,450)in Germany. The bi-Xenon lights turn with the car, but not necessarily with the steering wheel (as has been the traditional way to engineer such things). This car hooks its satnav into the central computer, so it knows exactly where it is and what parts of the road it should light up.

The LED system provides the best lighting, though unlike halogens or bi-Xenons that generate their heat at the front of the light (which can easily be cooled by the passing air), LEDs get hot at the back and need their own cooling fans, which makes them more expensive.

They won't need replacing, though, because their lifespan is rated beyond the scheduled life of the car.

And even if they can't illuminate the road, that doesn't mean you won't be able to see, because the A6 also has the option of military-spec infra-red camera vision, complete with an algorithm that can identify errant pedestrians and warn the driver before they even reach the light cone.

That won't help in some countries, though, because the United Nations has a list of nations where it won't let Audi sell the infra-red option, because of fears it could be used for military or guerrilla purposes.

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