“The most powerful production Audi of all time” is how the manufacturer started the C6 RS6’s original 2008 UK press release. In 2020, the car starts from cold with a half a second of slow-motion whir. Both announce much the same thing: size, chaps, very much matters. Twelve years ago the world had been slightly inured to the idea of a V10-powered prestige car by the E60 M5, the first production saloon through the ten-cylinder looking glass in 2005. In 2020, the notion of a 5.0-litre bi-turbo V10 in a large estate car has recaptured its ridiculousness.
Of course, in 2008 all those moving parts were a means to an end. Now everyone wants to look under the bonnet and marvel at the leviathan packed, sardine-like, into an engine bay also accustomed to housing 2.0-litre four-pot diesels. Back in the day Ingolstadt wanted the headline and bragging rights over its nearest rivals, which included the Mercedes E63 launched a year before and packing AMG’s decidedly epic 514hp 6.2-litre V8.
The wet sump M156 was as naturally aspirated as a racehorse and made your eyes roll back in your head. The Volkswagen Group already possessed a V10 which did the same thing, but the even-firing, direct injected, all-aluminium unit Audi fitted to the RS6 was different. The parallel water-cooled turbochargers were there to deliver the death blow: 579hp and 479lb ft of torque from 1,500rpm - 95lb ft more than the M5 produced at 6,100rpm; even slightly more than the larger capacity E63 motor managed at 5,200rpm.
Twinned with the latest generation of torque biasing Torsen centre diff and a six-speed tiptronic automatic, the two-tonne RS6 was claimed to hit 62mph in 4.6 seconds and certainly needed its limiter to step in at 155mph. But that was all grist to the mill: really it was all about that easy-to-find horizontal wall of peak twist, permanently at action stations should you suddenly want to whisk the family from 30-70mph in a single, wife-upsetting mega-waft.
Sound familiar? It won’t surprise you to learn that the V10’s capacity for in-gear ferocity is by far the most contemporary thing about the C6 in 2020. Virtually every mainstream performance saloon or wagon launched in the subsequent decade mimics its absurdly brawny mid range. Sure, there’s even less turbo lag now and much cleverer, quicker gearboxes (not mention smaller, faster revving engines) but the upshot is much the same: the RS6 is custom-built to make improbably fast driving accessible.
The kicker, unsurprisingly, is the sheer size of the motor. The V10 hardly bothers to shout - it is impressively refined on a motorway and not much louder under load anywhere else - yet its outlandish proportions remain front of mind. Naturally there is heft, the inimitable feeling of something substantial and expensive rotating behind the bulkhead, but even this doesn’t fully account for the interesting ink blot the V10 leaves on the psyche. It’s remarkably difficult to drive the C6 without a trace of swagger. It’s like packing heat.
It probably helps that the car now blends in. The current iteration of RS6 spurns any pretence of subtlety; it wants desperately to be on the radar of anyone in glaring range. In contrast the C6 doesn’t boast much about its blistered arches or bigger wheels. The front and rear are only lightly embellished. Debadge the boot lid and an anglican vicar could arrive at Sunday mass in Audi’s heritage car without drawing significant comment.
The interior hardly threatens to turn saint into sinner either. Sure, there’s a flat-bottomed steering wheel and fancy leather pews and the speedo tops out at 200mph, but otherwise the C6 is all business. That the car generally predates the industry’s predilection for drive modes is honestly a relief (the V10 has two settings: rapaciously thirsty and off) although it is comfortably new enough to deliver Bluetooth connectivity, rudimentary sat nav and even a DAB tuner.
Driving the C6 casually in 2020 requires no expectation reset. The step off is confident and while the V10 has many fewer ratios to play with than the modern equivalent, it hardly needs them. Gently encouraging more from it doesn’t inevitably result in a downshift; often the tiptronic will be inclined to let you lug it out. And that’s absolutely fine. Not least because it makes the paddles seem less redundant than then are in the current RS6. Pulling on one because you genuinely need a lower gear is rather novel.
Generally though you’ll be pulling on it to light the touch paper. Doing this with some lock on is the best way to highlight the C6’s advancing years. The car is furnished with Audi’s hydraulic Dynamic Ride Control system which lets the dampers confer with each other across the diagonal via a central valve and deploy additional force when required. Plenty sophisticated enough for 2008 when we all had middling, earthbound expectations for how much weight and lateral stress an estate car chassis ought to handle. In 2020, not so much.
A dozen years of bar raising has left the nose heavy C6 far behind the torque vectored and active roll-barred and obviously more rigid C8. The old stager steers no more pleasantly either; its stodgy power assistance an unwanted reminder that Audi faired little better with hydraulic systems than it does with electric ones. Fight through the weirdly contrived resistance and you’ll eventually locate the usual surfeit of mechanical grip underneath - but more often than not it is weight you notice carrying rather than speed.
All of which doesn’t hobble the C6’s claim to hero status one bit. Being merely able on a B road is acceptable when your reason for being was hoovering up autobahn at a prodigious rate. In that endeavour the car feels no less adept than it must’ve done at launch, which is some feat when you consider that the C8 delivers an additional 111lb ft of torque from its own twin-turbocharged V8. Unlike the chassis, the V10 was not merely a stand-in until its maker dreamed up something more capable; its output was intended as the car’s standout feature, and still feels it more than a decade down the line. That Audi declined to share it with another model, and wouldn’t build a more powerful engine for years says much about the V10’s legacy. That half a second of whir tells you the rest.
SPECIFICATION | AUDI RS6 (C6) / AVANT
Engine: 4,991cc, V10 twin-turbocharged
Transmission: 6-speed automatic, all-wheel drive
Power (hp): 580@6,250-6,700rpm
Torque (lb ft): 479@1,500-6,250rpm
0-62mph: 4.5sec / 4.6sec
Top speed: 155mph (limited)
Weight: 1,985kg / 2,025kg
MPG: 20
CO2: 331g/km / 333g/km
On sale: 2008-2010
Price new: c. £77,400 / £79,400
Price now: from £16,000
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