Audi S6 and BMW 550i xDrive in the comparison test: Sporty businessmen with V8 biturbos

With V8 biturbos, 444 HP and all-wheel drive, the BMW 550i xDrive and the Audi S6 possess the same assets, but interpret them in entirely different ways. Two power saloons in the comparison test.

You are certain to remember: not all that long ago the four-litre V8 from Audi arrived – in the S7 Sportback. That's right, that was the edition in which it was put to the test with the Porsche Panamera GTS (hier, from which it received a proper beating in honour of the added power. And in fact such a beating that many people could only explain it as being a personal preference on the part of the author towards the Porsche brand.

The Audi S6 with a fighting weight of 1,952 kilograms

One reader's letter said that you got the impression, "that a Fiat 500 was being compared with a supernatural car". Quite honestly: in some regards this was actually how it seemed. Three seconds separated the two cars in Hockenheim - and an equally hefty 40,000 Euros in price. Opinions are of course divided as to how important each of these two aspects in within this vehicle category.

We are interested primarily in the former - as always, the name says it all. The latter is more a means to an end. And especially with cars such as this, the athleticism of which is not physical, you have to get your wallet out: torque vectoring systems, ceramic brakes, the chassis - only with these features are the cars any use. That is to say: a Panamera like this is not simply fast and expensive - it is essentially as fast as it is expensive.

On this basis, this race is to be a close one. Both - this much is anticipated - on the final straight and on the starting grid, where there is only around 2,000 Euros separating the Audi S6 and a BMW 550i with xDrive and a sports automatic. On the one hand the Audi S6 will be put to the test: with essentially the same build as the S7, with the accosted four-litre V8, 550 Nm of torque and a fighting weight of 1,952 kilograms.

n the other hand the BMW 550i xDrive: likewise featuring a biturbo engine, likewise with eight cylinders, but with an additional 0.4-litres of engine capacity, an additional 100 Nm of torque and 69 extra kilos. In short: a dual between two self-confessed businessmen. Refined, high-classed, sophisticated - one might think. However, behind the façade there's rages a veritable kindergarten fight: between Audi and BMW in general and here specifically.

A more aggressive outfit for the Audi S6

The pair are continually pestering one another, especially when it comes to horse power: the 4.4-litre biturbo in the BMW 550i initially began with 401 HP, then along came Audi with 414 HP, before both have now officially agreed on 444 HP. On peaceful terms? What do you think?! For with its hefty 330 kW, strictly speaking the BMW comes in at 443 rather the communicated 444 HP (rounded up to 450 rather than 449 in the German metric system), on account of which Ingolstadt gladly pointed out that since the model upgrade, the Audi S6 does actually have over 331 kW. Only marginally: my son is five and with him, squabbling like this is generally followed by a cry of "nah-nah-na-na-nah!"

In any case, the difference here is really not a matter of power, but rather in the respective direction – and in the resulting contrast of appearance. BMW understands the 550i to be a rather conservative car: CEO-types, single-breasted suits, neckties, perhaps a little podgy, completely self-assured and confident, but maintaining a respectful distance from M GmbH. The Audi S6 is completely different. As the second most powerful V8 within the A6 range, it essentially does fill the same position, but performs the role while looking visibly more on the offensive: more aggressive dress, unambiguous dialogue and a much more harsh approach when dealing with others and itself. Motto: Get the job done rather than sit twiddling your thumbs

And the Audi S6 executes this in ice-cold fashion. So too in the interior: diamond-stitched seats, an Alcantara roof liner, perforated leather steering wheel, inlays made from carbon and contrasting stitching in moon-silver - better known as light grey. All of this seems modern and stylish, and ultimately invites you to drive rather than linger Barely behind the wheel of the Audi S6 and you reach for the start button as if being remotely controlled, and simply want to get going. Your fumble for your belt and make your way down from the pit area, so that you can really shake the dust off your bones.

The fully animated instruments are irritating in the BMW 550i

The BMW 550 i xDrive takes an entirely different approach to stress management. It is less a getaway car and more a haven of peace. With a soft-close feature, the door gently clicks into place – and you are already detached from the hectic goings-on outside. And then you sit there, sealed off by the rear blind and acoustic glass, and pull on the slider controllers of the zig-zag seats, before the V8 steps up with a tender purr to perform its duties in the test. Throttle response, power distribution, gear-shifting tactics – everything is perfectly harmonised in the BMW 550i xDrive, feels smooth, completely slowed down, but nonetheless still sweeps you away.

At one-quarter throttle, the engine rests, as a silent reserve that you are keeping up your sleeve, it rockets forward seamlessly and overwhelms everything around it with torque. A generous 650 Nm surge forth into the all-wheel drive system. Sustained and as soft as it is soft as it is hefty. Tip: order the BMW 550i without a model badge, then it won't cause a stir, but will arouse passion all the more.

But even if you are just going with the flow - with your sleeves rolled up, easy listening playing from the B & O sound system, the speedometer at the end stop -, you won't quite achieve perfect bliss. The most irritating thing with the fully animated - thank God optional - instruments. They are neither in keeping with the cockpit ambience with piano lacquer, cinnamon-brown leather and ceramic features, and nor with the mindset of the tradition-loving BMW clientèle, who until now only had the digitalisation of the consumption display to complain about.

The Audi S6 is more dynamic and more direct

In addition to this, as author of this story, you are continually struggling with the thought as to how a genuine all-rounder, as such that you really can't win. We'll make it quick, as it won't be painless: the BMW 550i xDrive may be an exceptional car, and a fast one that is not too portly to boot, however, in the test the Audi S6 is out in front in every regard. At least in every regard that is of relevance here. It's all in the name - as you well know.

In principle it is the same story as two months ago with the Panamera and the S7. As was the case back then, the second-placed car didn't actually do anything wrong in and of itself. And like back then ,the basic differences in the drive dynamics were only large on account of the performance extras. Two things made the primary contribution to the dominance of the Audi S6: firstly the dynamic steering and secondly the sports differential, which supplements the variable power distribution of the all-wheel drive with wheel-specific power distribution along the rear axle.

If both systems are set to "Comfort", the Audi S6's advantage is reduced largely to the superior feeling - the firmer overall tuning and the more intense, if not particularly sensitive feedback. If you switch to "Dynamic" in the test, then the Audi S6 fulfils everything that its appearance promises: the almost two tonnes of unladen weight and their top-heavy distribution are, of course only up to a certain point, let loose. In comparison to the BMW 550i xDrive, however, the Audi doesn't throw itself into the corner with much more spirit, but does develop much more body tension during the course of the corner. In other words: the Audi takes corners, the BMW gets them over and done with.

BMW 550i xDrive completes the Short Circuit in 1:16.8 mins

The paradox with the BMW 550i xDrive: as in normal life, when the casual power distribution palms one or two dozen km/h off on you, as it progresses the fast lap feels more subdued that it actually is. First of all, the steering lulls you in – or to put it better, its entirely indirect transmission. In contrast to the Audi S6, which you consciously pull into the corners from your wrist, in the BMW 550i it sometimes feels like you are flicking through the pages of a folded newspaper.

Pretend that's what you're doing and then you'll understand what I mean. To get to the point: based on the sluggish steering response, the tendency towards understeer and the roll-ristance-optimised Michelin tyres, the time of 1:16/8 on the Short Circuit is more than acceptable for the BMW 550i. Especially – a legitimate objection – seeing as the car stepped onto the ring with no M equipment whatsoever. However, BMW doesn't offer much that is of drive dynamic relevance for the 550i either. Mixed tyres and 19-inch rims were installed, with only the sharper integral rear-axle steering and the M sports chassis. The former is superfluous on account of the all-wheel drive; and the latter – optimistically calculated – would have perhaps knocked off half a second, which would have meant that the Audi S6, with its time of 1:15.2, would have safely won the contest in the test either way.

And there's more: according to points, Audi even manages to gain revenge for the botched opening match against the Panamera GTS. Granted, on the track it can't come close to the Porsche, however, with its – in comparison to the S7 – more focussed cornering in the dynamics disciplines it got close enough to pip it to the post thanks to the price section. In so doing the Audi S6 is not counted among the career-oriented, who strive for success above all else. On the contrary: it knows how to convey performance, even in more casual settings, roaring, rocking and rumbling through the optional sports exhaust with a wonderful lack of inhibition and, in spite of the puffed out turbo-charging, it still lets you feel the rhythm of the pistons.

Thus, the author's preference should be fairly obvious, even though as was already the case regarding his reported love affair with the it is not a personal preference, but rather a professional one.



10 May 2016
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