Independent Road Test: So light, it slinks without slurping

Gavin Green on the abstemious new Audi A8

In all the recent brouhaha about new Jaguars and new Range Rovers and other ``mould-breaking'' luxury cars, little has been written about fuel economy improvements. The simple reason for this is: there have been none.

Oh yes, there have been some gains in small-and medium-sized cars, and even in the executive sector (four-cylinder versions of the new Vauxhall Omega, for instance, are commendably abstemious). But at the top end, where flash badges and big engines and acres of interior room and leather and polished tree are all the rage, fuel economy has never been much of an issue.

Why? Because it does not sell cars. If you can afford to spend 30-grand or more on a car, then you can afford to pump in as much unleaded fuel as necessary.

One of the reasons why cars in the luxury class continue to slurp as they slink along, is that they are so heavy. This is one of the things that makes the new Audi A8 so refreshing. It is much lighter than its rivals. (It is also beautifully sculpted - one of the most handsome luxury cars ever launched - which is probably a much greater sales card.)

The Audi is light, because it is made from aluminium. And it is not only the outer panels that are aluminium: Land Rover has been using that trick for years. Rather, it is used for the sheet metal and the chassis. The chassis is a complex lattice-type frame on to which sheet aluminium panels are integrated, sharing the load bearing. Audi reckons body weight had been reduced by about 140kg compared with conventional steel. The basic A8, for instance, weighs 1,500kg, about 300kg less than the latest Jaguar saloon.

Less weight means lower fuel consumption - partly because smaller, more frugal engines can be used. The basic A8 model, as tested, gets by with only a 2.8-litre V6 - very small for a car that is meant to do battle with 4.0-litre Jaguars. It is also pleasingly brisk, if no tearaway.

But aluminium is expensive. Ask most rival car companies what they think of the Audi A8, and they will laud the company's technological boldness while predicting commercial suicide. Even Audi admits that, at present, the technology is only suitable for low-volume cars; it will be years before a Mondeo or a Cavalier could be made from anything other than steel.

The stance of the A8 is superb. While Ford has gone to great lengths to make its controversial new Scorpio eye-catching, by styling an odd-looking grille and tail, Audi has made its new charge eye-catching by simply getting the basic proportions right. There is nothing gimmicky about the A8, it is simply a singular piece of architecture.

The cabin is pretty good, too: roomy, beautifully finished and well appointed, although some of the switchgear is too small and fiddly. The boot is vast, and the lightweight lid opens completely upright, facilitating loading.

Sad to report, then, that as a driver's car the 2.8 version of the A8 is unexceptional. It goes well enough and uses fuel parsimoniously for so large and roomy a car. But it seems to me that Audi has put so much effort into getting its top-range flagship model right - the 4.2-litre V8 quattro - that it has rather forgotten about the bread-and-butter front-drive V6 - pounds 12,200 less and likely to outsell the quattro by four-to-one.

The quattro has four-wheel drive, which gives it superb handling and traction, and a special rear suspension to match. It is breathtakingly fast for so big a car, helped by the light weight, and has a peach of a gearbox - Porsche's Tiptronic automatic, which has a separate selection plane for manual shifting.

The basic V6 gets none of these goodies. Like all big front-drive cars, the handling balance is never quite right; it always feels nose-heavy. The auto shift is good but sometimes, such as entering a village after a cross-country dash, the ``thinking'' auto box will not keep up with your mood swings, and you will have a real jolt of a gear change. The V6 engine is fine, smooth and fast enough, but when you drive the V8 you soon realise what performance you are missing. It is also a little flaccid in the middle ranges compared with the brawniest competing six-cylinder engines.

Normally, it is better to buy the bottom car in the range. Flashier badges and bigger engines usually mean more profit for the maker and less value for you. But with the Audi A8, there is only one model to aim for: the pounds 46,699 V8 quattro. It is probably the best luxury car in the world, as well as being the most advanced.

The A8 2.8 V6, on the other hand, is an almost car. A technological tour de force on paper, it does not feel as special on the move. But it is economical.

COMPARISONS

BMW 730i, pounds 39,800

Faster, better to drive, but very conservative to look at. Much pricier, and not worth the extra over the A8.

Jaguar XJ6 4.05, pounds 34,950

Traditionally, rather than progressively, styled. Better ride and handling than the Audi, but not nearly as roomy. Faster, thirstier. Good value, and our choice in this price bracket.

Lexus GS300, pounds 31,950

Little brother to the superb LS400 - and not nearly as good. Cannot compete in this company.

Mercedes-Benz S280, pounds 37,500 Vastly roomy, quiet, but rather a slug. Gawky looks. Beautifully built, though.

SPECIFICATIONS

Audi A8 2.8 pounds 34,499

V6 engine, 2771cc, 174bhp. Four-speed automatic gearbox. Top speed 140mph, 0-60mph in 10.0 seconds. Average fuel consumption 26.7mpg.

(Photograph omitted)