Tuesday 12th April 2016

Mercedes-AMG S63 Cabriolet: Review

Well of course we went straight for the AMG version

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It's been so long since Mercedes-Benz killed off the W111/112 Cabriolet even it can't quite remember the reason it never replaced one of the world's more glamorous drop-tops. It might have been the oil crisis, or perhaps it was the general recession around the same time that did it in. Rumours of 'dangerous' convertibles being outlawed in the US certainly can't have helped. Whatever the reason, five decades is a long time to wait.

Quietly cruising a boulevard on the French Riviera on a chilly April day as the heated steering wheel lightly grills my fingers, the centre armrest roasts my left elbow and the driver's seat fans my buttocks I'm willing to forgive and forget. Stylish, classy, quiet and sophisticated; I am none of these. But the S-Class Cabriolet is all of the above and, among the Ferraris, Rollers and Lamborghinis, looks right at home.

I've never felt more of a fraud behind the wheel. But, as Airscarf breathes warm air down my neck, first impressions are that Mercedes has absolutely nailed it.

Big top
Featuring what's claimed to be the largest fabric roof ever fitted to a production car, the S-Class Cabriolet switches from drop-down poseur to cosseting roof-up recluse in just 20 seconds. It'll do it at speeds of up to 31mph too. All as expected. But what about those V8 BiTurbo badges on the wings and the liberal smattering of AMG logos?

Surely even Affalterbach's finest can't make a sports car out of what is, by any stretch, a whale of a machine? Expecting a thousand-yard stare when I meet the man in charge of the AMG S-Class project, Oliver Wiech isn't the nervous chain-smoking wreck you might imagine. Asking him if both the S63 and S65 has been his toughest gig yet he laughs.

"Absolutely not, not even close. The S-Class Cabriolet was actually pretty straightforward," he says. "For sure, early on we were very worried when we heard it might be a four-door convertible, but as soon as we saw the final plans we knew we could make a pretty good car."

The work began with the engine. The standard S500 has a surprisingly powerful 455hp twin-turbo 4.6-litre V8 but AMG junked it for its own 585hp twin-turbo 5.5-litre V8. If that's not enough the structure is also beefy enough to cope with the 630hp 6.0-litre twin-turbo V12.

The S63 shrugs off any ounce of respectability and launches itself to 62mph in an exceedingly rapid 4.2 seconds. The monstrous S65 is, unsurprisingly, quicker still but by just a tenth, the engineers admitting it is "traction limited" by the 737lb ft of torque.

Weighting game
To help tame weight - all things relative - engineers ditched the S500's lead acid battery and replaced it with a lithium ion pack - this alone shaves around 23kg off the kerbweight. Lightweight forged wheels and 20 per cent lighter ceramic brakes (optional) also help but in the scheme of things the changes are only modest and the S63 weighs in at 2,170kg, 55kg heavier than the S500.

So the chassis has its work cut out, Oliver and his team increasing camber stiffness, fitting chunkier suspension knuckles and adding thicker anti-roll bars and firmer bushings. The steering rack is also quicker. The subsequent increase in cornering speeds meant a redesigned lower A-arm, while at the back there's a stiffer subframe carrier. All S-Class cabs come with Mercedes adaptive Airmatic suspension but the S63 gets burlier pistons and AMG specific calibration.

The S500's new 9G-Tronic gearbox is also left on the shelf, AMG sticking with the tried and tested seven-speeder with its lock-up clutch. For left-hand drive markets almost all S63 versions will be all-wheel drive. Rear-driven right-hand drive markets aside almost 90 per cent of all AMGs now sold are all-wheel drive, suggesting the end of another era will come when this car is replaced.

Run for the hills
Wafting about on the seafront the V8 burbles a low, bassy tone ideal for posing. But it still doesn't suggest a sports car. Leaving town, Sport mode unlocks its full vocal range but it still sounds a little grown-up and mature for a full-fat AMG. The pace certainly meets expectations though. This 4Matic version is faster than the rear-driven one we'll get, taking just 3.9 seconds for 0-62 - two-tenths faster than the range-topping S65.

In normal conditions the system is rear-biased, shuffling 33 per cent of available torque to the front axle and the remaining 67 per cent to the rear. By now it's raining but not a single horsepower is wasted. This has the unusual effect of actually making the 585hp feel quite sedate.

When the long straights give way to sweeping bends it's easy to feel the benefits of the suspension updates. The safety understeer and roll in the S500 is notably reduced, the steering is sharper and - yes - the S63 feels smaller than its intimidating dimensions suggest.

Hauling iron
A special mention must also go to the optional ceramic brakes. Quite why you'd want, or need, them on your S-Class cab I'll never know - but at low speeds they're progressive with plenty of initial bite and, even with severe abuse, never show any signs of strain. As the road slows and the corners tighten, the inevitable weight of the S-Class cab catches up with us. Any hopes of traditional AMG hooliganism are dashed by the amount of traffic and traction of the 4Matic powertrain - there's a degree of slip but a born entertainer it is not.

That said, it easily edges the equivalent and 310kg heavier Bentley Continental GT Convertible. The S63 also rides better, even on its optional 20-inch rims, and steers and goes harder. Don't kid yourself though; it still lacks an important component for a true sports car (namely a roof) and is simply too hefty to hustle.

Our man Weich accepts the point but reckons the target audience will be more than satisfied. Better for us, he reckons the rear-driven ones we will get in the UK will be a little more engaging to drive.

So he's happy. But having said this car was relatively easy to develop, the temptation to ask him what was his most difficult project is impossible to resist. He replies without hesitation before staring into the middle distance. "Oh my god, it's the E-Class!" he laughs. "It's a car that has to be comfortable for business but be capable of being driven very fast on track."

The tension in his face relaxes into a grin though. "You will absolutely love the new one!"

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MERCEDES-AMG S63 CABRIOLET 4MATIC
Engine: 5,461cc, V8 biturbo
Transmission: 7-speed auto, four-wheel drive
Power (hp): 585@5,500rpm
Torque (lb ft): 664@2,250-3,750rpm
0-62mph: 3.9sec
Top speed: 155mph
Weight: 2,185kg (EU, with driver)
MPG: 27.2 (NEDC combined)
CO2: 244g/km
Price: £135,765*
*Pricing for rear-wheel drive S63

[anonymous-user]

Oh I like this, a reminder of what Mercedes used to be before they started chasing the money with tasteless, chintzy, poorly made FWD dross for social climbers.

Come on depreciation, do your work.