Solid, sensible, dependable. As the 1970s drew to a close Audi was a widely-respected marque – but not one which would have car enthusiasts drooling. German cars which were capable of raising the pulse rate were the preserve of Porsche, BMW, even Mercedes-Benz, and the crowds which packed their motor show stands each year proved the point. The cars Audi had on display were often quietly impressive, but there was never a crush around its stand. Until Geneva, 1980.

Pride of place on Audi's Geneva Motor Show show stand that year was taken by an angular coupe which boasted a new turbocharged version of the quirky five-cylinder engine. It was bound to be fast and exciting – but most interesting of all, it had four-wheel drive.

Driving all four wheels was nothing new, of course. The Range Rover was well-known, and there had been four-wheel drive off-road vehicles long before that. The Ferguson Formula four-wheel drive system had been around since the '50s. But few manufacturers of high-performance cars explored the possibilities, Jensen being the exception with its FF, which was based on Ferguson technology.

Most engineers thought four-wheel drive systems were too heavy, bulky and inefficient for use in performance cars. When a car corners, its inside wheels take a tighter line than its outer wheels, and the outer wheels have to travel faster to keep up. The differential feeds power to both wheels but still allows them to rotate at different speeds. In a four-wheel drive transmission there naturally has to be a differential in each axle. But there must also be a central diff to allow for differences between the speeds of the front and rear axles, as the rear wheels tend to follow a tighter line than the fronts. These additional diffs add weight and take up space.

Audi’s breakthrough was to integrate the centre differential into the gearbox. The gearbox output shaft was hollow, not solid, and drove the centre diff's pinion cage. The pinions drove a pair of bevel gears, just as in a conventional differential. One bevel gear took drive to the rear wheels, while the other was connected to a shaft which ran forwards, though the centre of the hollow gearbox output shaft, to the front axle.

With the car travelling in a straight line, the centre diff rotated at the same speed as the gearbox output shaft, so there was little extra frictional loss. Compared to previous four-wheel drive layouts the Audi system was beautifully light and compact.

Mated to that turbocharged five-cylinder engine, which developed 200bhp, the result was a drivetrain which made the quattro astonishingly swift and sure-footed, regardless of the conditions. The more inclement the weather and the more friable the road surface, the more impressive it became. Audi soon added four-wheel drive versions of other models to its range. And confusion reigned.

All of them carried the quattro moniker; eventually the normally-aspirated Audi Coupé became available as a quattro – so Audi had a Coupé quattro and a quattro coupé, but they were very different cars. The term 'ur-quattro' meaning 'original quattro' soon came to denote the earlier car.

The ur-quattro was soon upsetting the World Rally Championship applecart in the hands of Hannu Mikkola, Michele Mouton and Stig Blomqvist. But it was unnecessarily large for rallying, so Audi created the Sport quattro, a shorter-wheelbase limited edition version – a kind of quattro caricature. A foot was lopped out of the wheelbase and overall length was reduced by 10in, but the wheel arch blisters were bigger, the windscreen was more upright and the bonnet was distended in a huge bulge. Under it sat an all-alloy straight five engine with four valves per cylinder, developing 306bhp in road trim and a colossal 450bhp in the rally cars.

Never before had a rally machine developed – and been able to utilise – so much sheer grunt. Sadly the Group B-homologated Sport quattro and the even more extreme S1 which developed from it had a short-lived career, as Group B was abandoned following Henri Toivenen's fatal accident in Corsica in 1986. What survived was the idea of a multi-valve head for the in-line five as a route to higher output. Eventually, in 1990, the quattro was given the later 2226cc version of the five-pot engine, with a twin-cam, 20-valve cylinder head, and by this time the quattro transmission had been revised to include an automatically-locking Torsen centre diff, leaving the driver with manual control over just the rear differential. 'Our' car – Audi (UK)'s own ur-quattro – is one of these later 20V models, a well-kept 1990 car in pearlescent white, with less than 56,000 miles recorded on its digital dash.

Back then this was a £30,000 car, but as you take your seat you'll be wondering what they spent it on. The moulded plastic dash seems pedestrian, the column stalks feel cheap, and the door shuts with tinny clang that's more like a Metro than a Mercedes.

It can be difficult to get comfortable, too, as the steering wheel is offset to the left, so its hub is directly above the clutch pedal. Still, there are compensations – half-leather seat trim with unique 'quattro' cloth for the seat facings, for example, and a small, heavily-sculptured, leather-bound steering wheel which fits comfortably into the hands. The steering itself is pleasantly light, but also irritatingly noisy. Turn the wheel a few degrees from the straight ahead, and it clicks. Turn it further, or back again, and it clicks once more. It's as though each manoeuvre is being recorded by a microswitch, for later analysis by some humourless Teutonic statistician. Maybe a warning light comes on after 10 million clicks, indicating that the steering rack needs greasing. Or maybe not.

Straight ahead is the digital dash which the quattro gained in 1983, and which seems to have been irritating people ever since. The big digital speedo didn't bother me much, but I did find the bar graph voltmeter and oil temperature gauge difficult to interpret at a glance.

And oil temperature is important, because it's good form to give the engine oil a chance to warm up before giving the motor any hard work to do – something which applies to any engine, but particularly a turbocharged one. Once the bar graph has clicked upwards a notch or two, it's safe to deploy another inch of right toe.

The 20-valve engine develops its maximum torque at just 1950rpm, so there's always a half decent response to the throttle. But it's at its most impressive if you keep it spinning at 3000-4000rpm, where the rather flatulent low-rev engine note hardens into a metallic howl and the quattro launches itself towards the next corner.

Swift gearchanges need care thanks to an occasionally-notchy gearbox and a clutch which bites near the top of its travel. If you're clumsy with the clutch you'll be rewarded with one of the quattro's extensive range of characterful little noises, in this case a metallic clenk from somewhere underneath, presumably the noise of the centre diff taking up the slack. Shortly after this you will probably apply the brakes, and hear a tswit which is, no doubt, servo-related. Cruise at just the right speed and – there it is, it's a vibratory nark from somewhere. We're still trying to figure out the muffled tunk tunk which sometimes emerged from the general direction of the back seat – and before you ask, they were unoccupied at the time.

A sound you are unlikely to hear is the squeal of tortured rubber. A standing start using lots of revs might cause the wheels to spin for about half a turn, then the quattro just bites into the tarmac and hurls itself down the road. If you're committed or careless you can turn in aggressively enough for the outside front tyre to complain, but mostly the quattro just takes the bends you throw at it and deals with them, with a hint of stabilizing understeer but absolutely no fuss.

If you want fuss, though, the quattro will happily provide it: just burble gently down a busy high street and watch people's reaction to the car. Petrolheads will recognise the quattro and turn to watch it until you disappear from view. Even the less well-informed seem to get the message from the Audi's purposeful stance and no-nonsense demeanour, created by English stylist Martin Smith and perfected in the 20V quattro, with its wider, more purposeful rubber and lower ride height. The pearlescent white paint helps, too: it's nothing if not eyecatching.

Since the days of the ur-quattro Audi has proved, with cars like the RS2 and the TT, that it is capable of making cars to quicken the pulse. And the quattro? It still has the ability to draw a crowd. Just like it did in Geneva, 20 years ago.

Ten years of the q-cars

The subtle improvements – and wild derivatives

The first quattros used a 2144cc five cylinder engine, which had 10 valves driven by a single overhead cam. Power was distributed through a centre differential to the front and rear axles, the centre and rear diffs being manually lockable. For 1983, cable operation of the diff locks was replaced by a pneumatic system. A two stage pull-out knob locked the centre or centre and rear diffs.

Audi's rally drivers complained that the quattro was too big for twisty stages, so a Sport quattro with a 12.5in shorter wheelbase and an all-alloy 20-valve engine was introduced at the '83 Frankfurt show. Rally versions boasted 450bhp – the road-going version made do with just 306bhp.

Reacting to criticism of the normal quattro's gearing, Audi revised the ratios at the end of 1983, adding anti-lock braking at the same time. Wider tyres in modified arches and uprated suspension were added in '84, and the styling was tidied up.

A Torsen diff replaced the conventional centre diff for 1988, and the manual rear diff lock now disengaged automatically at 25km/h (about 15mph).

The big news for 1990 was a 2226cc, 20-valve dohc engine that the 20V quattro shared with the softer Coupé S2 – which effectively replaced it in 1991.

Traction in Action

The quattro turned rallying into a four-wheel drive sport

Michele Mouton and Hannu Mikkola gave the quattro its World Championship debut at the 1981 Monte Carlo Rally, and by February Mikkola had taken the team's maiden win in Sweden. Mouton won in San Remo – the first World rally win by a woman – and Mikkola was victorious in the RAC Rally despite rolling the car. Audi went on to win the manufacturer's title in 1982, with wins for Mouton, Mikkola and Stig Blomqvist. The quattro also dominated the British championship, winning five times.

Four more British wins and the '83 title went to Blomqvist – who celebrated by winning the RAC outright in Audi Sport UK's car, beating the official Audi World Championship team. Mikkola, meanwhile, won four World Championship events and wrapped up his first World title.

The Sport quattro helped Audi to another manufacturer's World Championship in 1984. The 500bhp Sport quattro S1 debuted at the 1000 Lakes in '85, finishing second. In Britain, quattros were successful in the hands of Malcolm Wilson and Walter Röhrl. The S1 was rendered obsolete when Group B was abandoned in 1986. Audi returned in 1987 with Group A cars, but the ur-quattro's rallying career was over.

Published in Classics magazine, August 2000