MOTORING : AUTO BIOGRAPHY

THE AUDI A6 2.5 TDI 140 ESTATE IN 0-60 SECONDS BY JOHN FORDHAM

LAST spring, Audi finally proved it could rival BMW on criteria other than common sense, ruggedness and efficiency. The advertising hoardings for the Audi A4's imaginative launch showed the elegant new saloon as an X-ray, emphasising that it definitely was a book you could judge by its cover. This, together with a stream of rave reviews in the motoring press, showed the company had caught up with its arch-rival on both panache and performance. The A4 was an attractive and beautifully engineered machine, and it was fun to drive.

The next model up, the A6, emerged at the same time - though inevitably in its groovier sibling's shadow, and thus to a more muted round of applause. The A4 was, if you like, the much improved descendant of the Audi 80 while the A6 was the former 100's offspring. The difference between those two older models was that the 80 was perceived as zippy, youthful and energetic while the 100 exuded a more considered, senior-exec gravitas. Likewise the A6. Though it wasn't as pretty as its smaller relative, it radiated refined predictability. On closer scrutiny, though, the only features that were significantly different were its front bodywork, lower cockpit and standard airbag.

With the addition of a 2.5-litre, 140bhp turbo-diesel engine, the A6 becomes a substantially different vehicle. For a start, this remarkable engine enables the car to accelerate to 60mph in just under 10 seconds, and pass the hazard of a lumbering pantechnicon in less than seven. But it's economical, too, achieving over 40mpg on a motorway cruise.

At anything other than idle speed or starting from cold, the A6 diesel engine is quiet enough to persuade you that it's petrol-driven. Its six- speed gearbox allows the engine to turn over so slowly in the top ratio (just 2,000 revs per minute at the top legal motorway speed) that it never sounds strained in fast use - and therein lies the explanation for the car's unusual fuel economy, too.

Audi's current range of diesel engines is a major improvement on its predecessors, and most of its rivals, the result of beefing up the pistons and injectors and refining the plumbing and electronic management. The result is a lot more clout and pulling power at low engine revs, permitting smooth, even progress with fewer gear changes.

Couple this fine engine with a very graceful estate bodyshell, and the Audi A6 finds itself up against another European rival - Volvo. There's not much to choose between the two marques for solidity and strength, and lately Volvos have moved into a different league of handling and performance from their cumbersome ante-cedents. But there isn't a Volvo power unit as economical as this one, and though the Swedish estates are legendary for swallowing a couple of three-piece suites and still leaving room for your pet elephant, this Audi estate has reasonable load-carrying capacity, too, and a much more luxurious and inviting interior. Audi instrumentation and facia design, of course, has the measure of just about any of its competitors.

Is the A6 diesel estate perfect? Well, no. Though the machinery isn't noisy at high speeds, the bodyshell and tyres are - and the handling is nothing like the silky A4 in terms of effortless agility. But at pounds 24,800, this is a very high-quality car at what, in this sector of the market, counts as a pretty fair price. Inciden-tally caravan-owners might like to know that the 2.5 TDi has just been voted "Diesel Towcar of the Year" by the Caravan Club.

GOING PLACES: Very sophisticated and powerful turbo-diesel unit; 0.60mph in approx 10 seconds, 50-70mph overtaking burst in fourth in approx 7 secs. Very slick gearshift, six-speed gearbox, giving quiet operation and fuel economy at high road speeds. Torque (pulling-power) excellent, with maximum clout of 214lb/ft at only 1,900 revs per minute.

STAYING ALIVE: Traditionally chunky Audi body, based on the earlier 100 model and complying with American side-impact protection not yet in force. Anti-lock braking, including the sophisticated electronic braking- force distribution (EDS) system, which adjusts braking effort to cornering factors and road condition. Steer-ing a little inert, likewise handling, but general safety and roadcraft standards excellent.

CREATURE COMFORTS: Very comfortable interior, with supportive seats. Adjustable steering column, driver's seat height adjustment, power steering, high-security central locking, split folding rear seats. Front and rear adjustable head restraints, electric tilt/slide sunroof, electric windows and mirrors, on-board computerised driver-info system on SE models.

BANGS PER BUCK: pounds 24,800 not a bad price for the quality, specification and frugality. Fuel economy 35mpg plus in urban use, 40mpg plus on motorways. Three-year dealer warranty, three-year paint defect warranty, six-year on-call roadside assistance and recovery.

STAR QUALITY: Build, cabin refinements, superb engine.

TURKEY QUOTIENT: A face-lifted Audi 100, apart from the engine. Handling unremarkable.

AND ON MY RIGHT: Ford Scorpio 2.5 TD Estate (pounds 21,760) - big luggage area, good ride, not so classy, unprepossessing front end; Volvo 940 2.4 TD Estate (pounds 22,100) - huge luggage area, quite smooth and speedy, old- fashioned looking, ugly interior; Vauxhall Omega Estate 2.5 Turbo (pounds 22,900) - big, surprisingly agile, attractive, but with some tacky trim items.