The Audi S6 is a phenomenal combination of immensely strong and tractable power, absolute precision in chassis dynamics - and luxury that starts at the in-car TV and doesn't stop until you reach the electric Recaros. Simply, the ability of the Audi to cover ground lightning fast with the utmost comfort, stability and safety is second probably to no other large four-door in the world. After all, how many other 250kW V8-powered sedans use constant four-wheel drive and also add to the mix the electronic ingredients of ABS, Traction Control and Automatic Stability Control?
In the way of all good cars, the S6 flatters the driver - but it is the sheer accessibility of its performance which is breathtaking. Put your foot flat to the floor and the five-speed auto will instantly drop back to a gear that starts the 40-valve 4.2 litre V8 torquing its infinitely rewarding journey to the redline. Listen to that utterly glorious note and you'll feel an involuntary smile tug at your lips as you revel in an engine that has immediately usable performance literally from idle to the 7500 rpm rev-cut. If you have an acute ear, on each gear change you'll sense the electronic throttle momentarily closing, the hard-edged sound again swelling once each ratio has been selected. But as with the other electronic aids, the slight dip in power on each gear change is not a source of annoyance; nope, it's simply another example of Audi's engineers integrating the mechanical and electronic systems to give you the very best in real-world performance.
And - unlike some other Audis - here is a car that is a totally cohesive package. At speed the steering is precise and well-weighted, the ride strongly damped and poised, and the car's ability to put its prodigious power down as it nonchalantly exits corners at full throttle almost beyond belief. The brakes are strong and progressive, the instrumentation clear and precise, and the controls well placed and logical. From moving at a walking pace in urban traffic jams - TV switched on and outside noises a subdued hum - to flicking the Tiptronic back to third as you turn at 110 km/h into a rural corner marked at 40, this is a car that achieves at a rarefied level indeed.
No, the S6 isn't perfect, but it's still the best car that we have ever driven...
The AUD$166,000 S6 joins the other Audi 'S' cars as the ultimate performance version of each family. Based on the V8 version of the A6, the S6 ups the ante from 220 to 250kW, adds wheel guards flared to accommodate the 17 x 8 Avus alloys, a more aggressive grille, aluminium fenders and bonnet, and upgraded lighting. The suspension is revised with new aluminium subframes front and rear and lowered progressive rate springs are fitted. Inside, the trim level jumps another step over the already luxo A6 4.2, with carbon fibre inlays on the doors, dash and centre console.
But the heart of the car is that incredible engine. The long-stroke design (B&S is 84.5 x 93mm) uses five-valves per cylinder, variable camshaft timing on the intakes, and a two-stage variable intake manifold cast in magnesium. The peak power of 250kW is developed at 7000 rpm, with 420Nm of torque developed at 3400 rpm and over 300Nm available "from only slightly above idle speed". Backing the engine in all the Australian-delivered cars is a 5-speed Tiptronic auto, which also boasts gear change buttons integrated into the steering wheel. Fourth is a 1:1 ratio, with fifth a 0.803 overdrive. Combined with a final drive of 3.511:1, the result is relaxed cruising and wonderful acceleration and response everywhere.
While others may hanker for a manual 'box, the auto trans and superb engine work together in scintillating accord. And vital to their cohesion is the electronic throttle software. As mentioned earlier, the throttle momentarily closes on gear changes - even when you're holding your foot flat to the floor. But the relationship between the engine, transmission and throttle goes much deeper than that. The Bosch 7.1 engine management ("The Bosch ME-Motronic System - Part 1" ) looks at the accelerator pedal position simply as a driver torque request, rather than the accelerator position dictating the actual torque outcome. In other words, the management software - rather than the driver - decides how much torque the engine will deliver. The responsiveness of the engine is therefore very much under the control of the engineers and software programmers - and on the S6, they have done a marvellous job.
About the only downer to the electronic throttle is that, until you get used to it, the sheer grunt available with small foot movements can fool you into being disappointed with the top-end performance. In fact, the power development of the engine is almost linear - but of course once you've asked for full throttle, the management system cannot give you any more that that...
Quantified performance includes a 0-100 km/h time in the high sixes, a standing 400 metres in the high fourteens, and a top speed of 245 km/h. On the road, the car feels faster than that - a corollary of the way in which the auto trans always has the engine working in its range of strong power delivery. Unfortunately, the flip side is fuel consumption that's difficult to get below 15 litres per 100km - in any type of driving.
The 5-speed trans is generally quite happy being left to do its own thing - the only notable deficiency is that just occasionally it audibly clunks into gear on trailing throttle. Otherwise it is creamy smooth both up and down the gears, the trans also being programmed to do some subtle engine braking on decel. But if you want manual control, simply move the selector lever across to the right to activate the Tiptronic function. Pushing the lever forward up-changes a gear; pulling back on the lever knocks you back a cog. However, even with the gear manually selected, full throttle will still cause a kickdown if a lower gear is capable of providing more acceleration, and the box will also up-change if you reach the redline. In practice this lack of definitive driver control is not a problem; if you want to really hold the car in a single gear you can always move out of Tiptronic and pull the main gear lever back. That way, if you select second gear, you'll stay in it until the engine hits the 7500 rpm soft rev cut.
The speed of gearchange is the same, regardless of whether you're Tiptronicing or simply leaving the trans in Drive. That's a touch disappointing - it would be nice to have firmer shifts when manually driving the car. Another minor criticism is that the steering wheel gear-change up/down buttons aren't sufficiently differentiated - knurling on either the '+' or the '-' would allow more sure selection when your hands are flying on the steering wheel. The wheel itself is a delightfully chunky, small diameter design. Disconcertingly light at parking speeds - you can literally steer with your little finger - the steering firms up at higher speeds. Unlike the Audi A3 Turbo tested a few weeks ago, the steering's linearity and precision are both excellent.
However, the driver is left with little feel for what the front wheels are doing, and when cornered over broken bitumen some steering rack rattle - not kickback - can be both felt and heard.
When compared with the sophistication of the engine and transmission, the four-wheel drive system uses a relatively simple approach. The nominal torque split is 50:50, with a centre Torsen diff mechanically controlling the power flow. This approach to constant four wheel driving gives a predictable, sure-footed feel - however, it is also a recipe for understeer, especially with the engine ahead of the front axle line. Sure enough, if you try to power into a tight hairpin, the S6 will (eventually) start to understeer. However, it can do no more than begin this process, because once the ESP system senses that the front is running wide, power is reduced and the inner rear wheel is braked, bringing the car back on course. And while the S6 can scramble through with the yellow warning triangle on the dash flashing, far better for both front tyre life and driving stability that very tight corners are negotiated with a relatively slow entrance - and then the awesome traction and power used to exit at a huge rate of knots.
It is a testament to the car that even when tossing it around tight mountain roads, the S6 never feels either large or heavy. At 1760kg and 4833mm long it is both, but the suspension control, brake feel and accurate steering convey the feeling of a much more nimble, lightweight car.
But even with its undoubted competence in this environment, it's not on narrow winding roads where the S6 shows its true brilliance. Instead, point it at a flowing strip of bitumen that ducks and weaves its way through verdant countryside; where even the steepest hills can be dispatched by a twitch of the right foot; where using the Tiptronic to select fourth gear gives a breadth of throttle control and power that allows the road to be reeled back at a rate that is simply astonishing; where the full-throttle kickdown makes passing moves - any passing move - a snack. We spent a week with the S6 mostly on the challenging and tricky roads of the Gold Coast hinterland; at times we shook shake our heads at the sheer brilliance of the car in that environment.
But a car wonderful on the open road but lousy around town wouldn't at all suit the 40 year old entrepreneur at whom Audi have aimed the S6 - just as well that around the city the Audi retains its brilliance. An almost soundproof car - even with the music system cranked up it's nearly inaudible from directly outside - the S6 excludes traffic, wind and road noise with the competence of a true luxury car. Only occasionally does the roar of the 255/40 Michelin Pilots intrude. And despite the firm suspension, the ride is quite acceptable - the electrically adjustable Recaro seats playing a major part in the overall comfort equation.
The combined Blaupunkt navigation, TV and satellite navigation system generally works well, although we have specific gripes with each function. The voice instructions of the nav system are irritatingly frequent - far more so than the rival VDO Dayton system, for example - however the system's speed of operation and the way in which data can be entered is very good. The radio has some functions that - even with a quick scan of the instruction book - remain hard to understand, while the CD stacker is still buried in the boot when other manufacturers can more conveniently locate multi-CD players in the dash or elsewhere in the cabin. When you're on the move, the TV screen blanks to carry an ungrammatical and slightly redundant warning, "For your own personal safety the TV picture will only be displayed while the vehicle is stationary". Finally, while the sound quality of the complete system is very good, it isn't quite up to the level that we would have expected given the presence of a boot-mounted Bose subwoofer and Bose speakers in each door.
Secondary safety is assured with a surfeit of airbags - frontal designs for the driver and passenger, side airbags integrated into the front and rear seat backs, and two front head-level airbags. Practicality includes the presence of a very long boot - complete with a luggage net - and plenty of room in both the front and back seats, although the driver's footwell is a little narrow. Unusually for a car of this type, the rear seat also split-folds flat, giving an enormous amount of luggage space. So not only do you get one of the world's best point-to-point performance machines, you also get the practicality and sheer usefulness of a booted, four-door car.
It's always easy to find fault - we don't like the fact that the car is provided with only a generic A6 - not a specific S6 - owner's handbook; the leather Alcantara trim used widely within the cabin will mark easily (it's even on the sunvisors!); the sunroof when fully open creates an unpleasant booming resonance when the car is moving; the telephone aerial is oddly unintegrated; the headlight high beam is woefully inadequate; and a car of this price and number of seat adjustments should have seat memories. And, more worryingly, our test car developed a front-end suspension clunk (later traced to a loose bolt) - just as well there's a 3-year unlimited kilometres warranty...
Part way through the test I was asked if I'd have tears in my eyes when I gave the S6 back. It turns out that I didn't, but I did feel a bit choked up....
This is simply one helluva car!
www.audi.com.au
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