Audi RS 4 Avant 2018 Review

Audi has a fine pedigree of creating savagely fast wagons. It began almost a quarter of a century ago with the legendary Porsche-developed RS 2 and continues to this day with the supercar-baiting RS 6 Avant. The latest, is the fourth instalment of the RS 4 that, on paper at least, reads like another victim of downsizing. That's right, the new RS 4 misses out on the old car's glorious V8 but, in reality, the move to a biturbo V6 has helped create the best RS wagon since the sublime B7 RS 4. Read on to find out if you'd pick it over a Mercedes-AMG C 63 S.

Audi struck performance car gold in 2006 when it created the B7 RS 4. The formula was simple: shoe-horn the R8 supercar's 4.2-litre V8 into the nose of the seven-gen A4 sedan and wagon, combine it with a slick manual gearshift and then gift the red-hot Audi with a supple well-damped ride and ensure its all-wheel drive directed most of its torque to the rear wheels. It was a winner.

The sequel in 2008? Not so much. To give it credit, the B8 RS 4 was a fine car, but only in isolation. Its V8, for example, remained a joy and super-quick dual-clutch 'box was easily a match for its frenetic nature, but beside far more muscular opposition like the Mercedes-AMG C 63 S, it was simply outgunned and had to be worked hard to keep up.

For the fourth-gen RS 4, Audi Sport (formerly quattro Gmbh), made some difficult decisions. First was to pension off the old V8.

To replace it, initially the mighty twin-turbo V8 that powers the RS 6 was considered but, ultimately, all its turbo gubbins meant it couldn't quite fit under the nose of the B9.

And the danger of the little RS wagon out-accelerating its flagship RS 6 wouldn't be good for business.

The next best thing was to use the far smaller 2.9-litre twin-turbo V6 that was co-developed with Porsche.

Featuring a shorter stroke than the 3.0-litre V6 that powers the lesser S4 and S5, the full-fat RS 4 mounts its twin turbos within the ‘hot vee’ for quicker responses.

The headline figure is the smaller, lighter twin-turbo V6 matches the 331kW peak power of the V8 but produces a whopping 600Nm – 170Nm more than the old naturally-aspirated 4.2-litre.

The transformative effect of all that extra pulling power is reflected in the performance delivered.

Dishing up all that punch from just 1900rpm, the all-wheel drive RS 4 now hits 100km/h in just 4.1 seconds and tops out, with the optional Audi Dynamic pack fitted, at 280km/h – 0.6sec quicker and 30km/h faster than the car it replaces.

That’s all the more impressive when you hear the RS 4 no longer employs the lightning-quick dual-clutch tranny, but uses a conventional eight-speed torque-converter automatic.

Like before, the small powerful Audi wagon comes with the German car-maker's famous quattro all-wheel drive system that, in normal conditions, sends 60 per cent of its power to the rear wheels. In more extreme conditions this changes to up to 85 per cent or, alternatively, up to 70 per cent to the front axle.

To help maximise performance, Audi claims to have shed 80kg over the last model, partly because – like the A5/A5 on which it’s based – it rides on the company’s latest ‘MLB evo’ platform.

But most of the saving has come from the small V6 that, alone, sheds 31kg over the V8. A further 15kg is lost using a lighter body, 3.4kg from a more compact electric power steering system, another 12.5kg thanks to a redesigned all-wheel drive and a single kilo from the new rear diff.

There’s another 8kg saved by ultra-lightweight 20-inch wheels and a further 8kg thanks to the new carbon ceramic brakes – although both are optional extras, with the latter likely to cost a ludicrous $11,900.

After all that, you might expect a stunning kerb weight figure but, alas, the RS 4 still manages to tip the scales at 1715kg (dry) about the same as a Mercedes-AMG C63 S wagon.

Sitting a further 7mm lower than the S4, the RS 4 comes with Audi's latest Dynamic Ride Control (DRC) that promises a clearer spread of ride quality between its Comfort, Auto and Dynamic modes.

In fact, confusingly, when describing a 331kW RS 4, Audi seemed most proud that the B9 is the "most comfortable RS ever".

From its gaping front air-dams to its 30mm wider body panels and added front and rear fender air vents (fake), it leaves you in no doubt of its performance car credentials.

Inside, the RS 4's cabin walks it for fit finish and sheer quality but it's behind the wheel that counts. However, fresh from our latest experience of the mechanically identical RS 5 coupe, will the Audi RS wagon be damned by another 'fast but not much fun' verdict?

Early impressions, around town, are concerning. In comfort mode, the RS 4 feels too quiet, too comfortable and too grown up for its own good. In other words, it plays the role of executive chariot perfectly.

Predictably, the blown V6 doesn't deliver the inspiring soundtrack of the old bent-eight, but that's small beer because behind the wheel you never miss the V8.

Same goes for the old car's dual-clutch box. The new eight-speed is so much smoother, still quick and intuitive and makes full use of the torque available and the all-wheel drive that seems astonishingly capable of deploying all that 600Nm with barely a tyre squeal.

Leaving the city limits we get the chance to stretch the small Audi's legs on long country roads. It's here that the comfort mode falls flat.

On roads that aren't billiard table smooth, the slightest bump creates an unchecked oscillation that gradually get worse and worse. It's not AU Falcon cab with half a million kays on the clock bad, but if you have kids and own an RS 4, expect a messy clean-up operation in your future.

'Auto' is a far better compromise and still perfectly comfortable, at least on the Spanish roads we drove.

'Dynamic' is best suited for tight and twisty corners but the extra weight it adds to the steering is unwanted. That and the sports exhaust begins to do a faintly embarrassing vuvzela impression.

Mercifully, there's an 'Individual' setting allowing you to customise all engine, transmission and chassis settings -- quieten down the racket made by the exhaust.

Back to the steering. All the cars we drove had the optional Dynamic Steering system that varies the ratio on the move in Comfort and Auto modes, but fixes it in its fastest ratio in Dynamic mode.

In the past, the system has robbed drivers of the connection between input and response but in the latest RS 4 it seems to be less intrusive.

Without a back-to-back comparison of a car with the standard rack it's hard to recommend it, but at least it isn't a barrier to driving enjoyment.

The little 2.9-litre twin-turbo is a joy and seems to always be on-boost and never caught out. When you reach your favourite road the new auto has an uncanny ability of sensing what gear is appropriate when.

Occasionally when using the paddles it can be reluctant to shuffle down the 'box in hard driving but the engine and transmission combination – plus mighty all-wheel drive traction -- translates into devastating cross-country pace.

On the tight, twisting alpine roads we drove, a keen driver pedalling a rear-wheel drive Mercedes-AMG C 63 S wouldn’t stand a chance of keeping the RS 4 in sight.

Helping make it such a rapid device is the phenomenal grip levels dished up by the Hankook tyres that manage to resist understeer at all costs -- even at unspeakable entry speeds into slow corners.

Pick up the throttle early and the RS 4 is happy to adjust its line with the throttle, but it's no oversteer hero -- at least on public roads at relatively sane speeds.

This might make the little RS sound a little one-dimensional but it still manages to be both involving and even a little intoxicating.

Factor in that this is a practical, comfortable mid-size wagon that can carry four, has a decent boot (505 litres) and can average 8.8L/100km at a push, and it's hard not to love the prospect of life with an RS 4.

No doubt the more theatrical Mercedes-AMG would offer greater thrills with its heroic soundtrack but living with one -- between epic full-bore acceleration and naughty drifts -- would be punctuated with your family hating you for its appalling ride.

Set to be priced around $155,000, all models Australian models will be well-equipped, coming with larger 20-inch wheels, the raspy, slightly annoying sports exhaust and the agility-boosting quattro sports differential.

The RS 4 is truly a return to form for the small RS wagon. Our roads will prove a far sterner test of its dynamics abilities, but after two days behind the wheel it's hard to think of a faster family car with greater all-round appeal for the performance enthusiast.