Audi RS5 2018 - ARABGT

The new Audi RS5: larger, lighter, quicker, cleaner and cleverer than the six-year-old model it replaces.

It is most of these things because alongside the latest MLB platform, Audi has finally swapped out the old naturally aspirated 4.2-litre V8 for the cutting-edge 2.9-litre twin-turbocharged V6 it has spent the last few years co-developing with Porsche.

Naturally, its superior numbers in almost every facet count as reasons to be cheerful – but history dictates caution here, and no little regret.

The previous unit was far more than just a tightly wound bundle of numbers; it was arguably one of the last great atmospheric engines, with a throttle response to die for and the kind of lean, caterwauling soundtrack that effectively had your vein spiked at 8250rpm.

We’d therefore be remiss not to sound a rhetoric last post at its departure and neon signpost the fact that it was easily the best thing about the last model, which fit Ingolstadt’s starchy stereotype about as accurately as a Paulaner brewer fits into lederhosen.

Broadly speaking, the old RS5 was too heavy, too anti-engagement and, over time, too obviously overawed by its rear-driven rivals from BMW and Mercedes.

The differences between new and old Audi RS5

A couple of the new car’s modifications, then, are notable out of the gate. It's lighter by 60kg in its regular format (thanks mostly to the 31kg-lighter V6), and UK examples get the mechanical rear Sport differential as standard to better compliment the quattro all-wheel-drive system and wheel-selective torque control.

The chassis is new, too, with a five-link arrangement at the front and back, paired with adaptive dampers (RS Sport suspension with Dynamic Ride Control is an additional option; ditto the RS exhaust system and the traditionally undesirable dynamic steering set-up).

There’s also a transmission change, with the V8’s dual-clutch seven-speed automatic making way for a ZF eight-speed torque converter.

That means the car shares an engine with the second-generation Porsche Panamera 4S, but not an entire driveline – the auto is a tweaked version of the S5’s automatic.

The V6’s output is different, too: Audi has eked out 10bhp more so it can claim to match the outgoing V8’s 444bhp. Peak torque, predictably, is dramatically superior, with the V6 summoning up 442lb ft from 1900rpm. At the same time, CO2 emissions have been slashed by 17 percent. 

This being Audi Sport, and an RS model to boot, it naturally looks the business. It signals a mild overhaul of the brand’s styling approach - although with its blistered arches, lacerated air intakes and porthole-big oval exhaust pipes, it establishes a familiar scene. The proportions feel about the same, too, despite the 74mm of additional length, which is predominately donated by the MLB’s larger wheelbase.

The RS5's interior also conforms to type: it's immaculate and brilliantly made and utterly endearing to touch and look at. UK models get Audi’s excellent Virtual Cockpit digital instrument panel as standard, and the test car we drove in Andorra had enough Alcantara on the door cards, steering wheel and gear shifter to neatly distinguish the RS5 from the closely related S5.

Other standard fitments on the RS5 include 19in alloy wheels, LED head and rear lights, an acoustically glazed windscreen and a wealth of Audi’s latest safety technology. Inside there is a pair of Super Sport electrically adjustable and heated front seats, tri-zone climate control, ambient interior LED lighting, and Audi’s MMI infotainment system with an 8.3in display, sat nav, DVD player, 10GB hard drive storage, DAB radio, smartphone integration and a 10-speaker audio system.

Firing up the Audi RS5’s twin-turbo V6

Start-up is slightly less auspicious. Audi Sport has persevered with the soundtrack –boldly equating it to the turbocharged V6 that powered the B5-generation RS4 – but its bass-edged waffle doesn’t cover the sound or reality of two substantial blowers whistling away betwixt the cylinder banks. The engine isn’t necessary captive to the rise and fall of the Sirocco, yet nor is it an unchained melody on the V8’s Richter scale.

That’s to be expected. And so is the type of performance, cranked like buttermilk from the distant churn once you’re underway. Where its predecessor dispensed progress in escalating staccato lunges at the redline, the V6 unfurls itself through the medium of the mid-range. Its surge is prodigious, unthreatening and seamless – any concern about the Tiptronic box’s lacklustre showing in the S5 is swept away by its sure handling of the many rhythmic upshifts required.

Around this entirely different sort of engine, Audi has moulded a palpably different sort of car. Claims made of its Gran Turismo status within the line-up are not (wildly, at least) overblown. Tested on super-heated stretches of deserted French autoroute, the RS5 can be characterised as easily the most comfortable car in Audi's line-up.

In Comfort mode, the traditionally nagging short-wave stiffness has been uncoiled by adaptive dampers with enough latitude to finally deliver a sympathetic and supple primary ride.

Tie in a dynamic steering system which actually comes good at outside-lane motorway speeds – i.e. competent and thickly accurate – and suddenly you’ve got a two-door RS car persuasively capable of crossing a continent. That the new V6 plays as compelling a part in that narrative as the V8 did in the old car’s motley charm is a massive plus in its favour.

Where the minuses occur, they do so with a predictable sense of inevitability. It hardly needs saying that the new RS5 is quicker than the old, and it feels it (there’s simply too much torque fermenting in the engine bay for it not to be) but there isn’t the same accompanying theatrical fizz to its high-rev function, nor the same pockmarked mechanical shunt to its paddle-operated gear changes.

That it proves less than mesmerising in such moments is hardly a shock, and it feeds into the RS5’s wider major shortcoming; specifically in handling which still gently refuses to ever come enthralling to life.

That’s not to say that progress hasn’t been confidently made: with less weight over the front axle and the locking rear differential in play, the car is plainly more agile than it’s ever been and can at least be goaded into delivering more drive to the outside back wheel.

But the adjustability is fleeting, and very promptly tidied up by the drivetrain even with the stability control switched out. Immodest amounts of speed or throttle will simply result in Audi’s age-old understeer remedy.

Perhaps that’s all forgivable against the backdrop of its maker’s penchant for massive directional stability – it’s rather less easy to absolve the ‘dynamic’ end of the dampers' settings (too firm even for Andorra’s roads) or the steering (too impenetrably frustrating for any road). 

Should you choose a V6 RS5 over a V8 RS5?

The best reason for doing so previously was to access the last resting place of the Audi 4.2-litre V8; a reason now manifestly gone. 

And to buy the latest RS5 solely for its new engine would probably be a mistake: the V6 is as consistent as treacle, and about as satisfying when warmly spooned into your life – but it’s not the kind of engine that stands dramatically out from the rest of the driving experience.

Any deeper appreciation of the new RS5 rests on a preference for the model’s tactful repositioning. Dig the monster GT vibe, and the car’s established gifts for interior splendour, technical prowess and sharp-edged looks start to make considerable sense – as does the generosity and seamlessness of the twin-turbo lump.

Seen from this alternative vantage point, which has almost nothing to do with the hard-charging, handling flair that exemplifies its rivals, the RS5 simultaneously appears limited and perhaps more appealing than it ever has.