Mercedes-Benz SL 63 AMG 2012 Review - International

Mercedes-Benz SL 63 AMG

The original SL 55 AMG came within one ultra-tricky, technical corner of winning MOTOR magazine’s Performance Car of the Year award in 2001. I know, I was there.

Up until it arrived in Shepparton on the last day, the SL 55 was engaged in a five-day arm wrestle with the Porsche Boxster S. It was a struggle that outlasted blasts up the Avalon airstrip, Victorian mountain roads, cruises on highways and whipping laps around Winton.

Anybody who has pushed a Boxster S hard knows what high praise that is, and the SL 55 is still held in high regard for its layer of utter luxury underpinned by balanced handling, driver feedback and an engine note that melts paint.

AMG sold 21,500 of them up to 2007, then sold another 5000 of its naturally aspirated, 6.2-litre successors up until last year.

Yet hopes of a like-minded replacement faded significantly when we drove the all-new SL 500 a couple of months ago. Technically brilliant, the new car used a lot less fuel, weighed a lot less and introduced a chassis that dripped with cleverness. The downside was that its design was old before it emerged, pre-dating both the current Benz design boss, Gordon Wagener, and last year’s SLK by a couple of years each.

The other downside was that the SL’s combination of a Active Body Control and electro-mechanical power steering effectively reduced the driver to a mere occupant.

AMG promised to right such wrongs. Though the powertrain stood up as one of the SL500’s highlights, it was never going to be enough for the Masters of Excess at AMG. Up front in the SL 63 AMG is a 5.5-litre, twin-turbo V8 that is not only almost as powerful as AMG’s own 6.0-litre, twin-turbo V12, but far more advanced. It not only has direct fuel-injection, but variable valve timing and it’s mostly made from advanced alloys.

In base form, it offers 395kW and 800Nm (yes, 800!). This is enough to fling it to 100km/h in 4.3 seconds.

It also has its own version of the maligned Active Body Control, and its own electro-mechanical steering system that does away with the variable ratio bit for a linear ratio. It sounds good on paper…

PRICE AND EQUIPMENT

Anyway, the SL 55 was a better car at a fifth the price and about the same weight. So I choose to ignore the SLR.

No, for the first time it has a viable, proper production AMG sitting above it. Now there is the roofless version of the stupendous SLS and it’s not only the most expensive AMG you can buy, but it’s also been pinned as the most outwardly sporty AMG convertible, too.

The hard fact is that, being about the same size as the SLS roadster, AMG felt like it had to find a new role for the SL 63 and that role is as AMG’s Grand Touring two-seat convertible. Boo, hiss, I hear you say, but the SLS’s existence, coupled with the lighter-but-lardy-feeling donor car made this new positioning inevitable.

Still, it’s not cheap. At €157,675 in Europe, it’s comfortably atop the SL 500, so you could expect a $300,000-plus price in Australia. Then there’s the Performance Pack which, in AMG’s tradition, adds more power and torque and, in Germany, another €14,280 to the bottom line.

Besides AMG’s own suspension and steering systems, it also gets AMG’s own braking system, a different gearbox, lots of unique hardware bits and some design tweaks.

The first of these is a standard set of 19-inch wheels and tyres (more of which later) with the option of a 20-inch rear setup as well. There is also a compound aluminium-cast iron brake system as standard fit, which you can change for the addition of serious-but-as-yet-undisclosed money to a big carbon-ceramic setup instead.

Around the body, it comes with LED running lights inside the SL’s disturbingly big headlights and a twin-blade horizontal strip across the grille, designed (as AMG development boss, Tobias Moers, said) to resemble two aeroplane wings.

At the back, there are four chromed exhaust tips, a lip spoiler and a diffuser, all surrounding a bootlid with a carbon-fibre structure bonded to a plastic panel, saving 5kg.

The roof comes in three versions, and all three fold away in 20 seconds (but you have to be almost stationary to get it done). The first is a metal roof, the second is clear glass and the third (and most expensive) version is the Magic Sky glass roof, which clears or darkens at the touch of a button.

MECHANICAL

At the heart of this particular AMG is the twin-turbo, 5.5-litre V8, code-named the M157, and it’s a terrific engine, even if it only revs to 6500rpm. At 5461cc, it’s a big bore motor, with a 98mm bore playing a 90.5mm short stroke to produce 395kW at 5500rpm.

And its pair of turbochargers ensures there is torque as well -- not normally the way of short-stroke engines. This one thumps out 800Nm from 2000rpm and holds it to 4500.

It’s enough engine to throw the SL 63 to 100km/h in 4.3 seconds and keep throwing it so that it only takes another 8.6 second to hit 200km/h. It’s limited to 250km/h, too, though there is a added-cost pack you can buy that ratchets that limit up to 300km/h.

Even so, it only uses 9.9L/100km on the combined cycle (about 0.8 litres worse than the stock Benz SL 500). Not bad, considering…

But there’s more. As with all AMGs, you can buy the Performance Pack that lifts the turbo boost from 1.0 bar to 1.3. It crunches out 415kW at the same 5500rpm, and hikes the torque up to a level that would make most truck drivers jealous. There is a small compromise, though, because its 900Nm arrives slightly higher, at 2250rpm, than the stock SL 63, and drops off earlier, at 3750rpm, though that seems a small price to pay.

The SL-PP claims the same emission and fuel consumption numbers, too, and slices a tenth off the 0-100km/h time but it’s, you know, more, so it’s better… Still, it’s 5kW less than the same engine’s Performance Pack delivers in the S-Class (though it’s more than you get in the E-Class), largely because the S-Class has more space to package more cooling stuff.

Both versions of the engine drive the rear wheels through AMG’s take on the seven-speed Benz automatic, which means they keep the basic casing, change the ratios, toughen up the cogs and rip the hydraulic torque converter off and replace it with an electronically-controlled clutch pack.

It’s one of the core things you’ll tweak with a fiddle of the knob marked C, S, S+ and M (for, respectively, Comfort, Sport, Sport Plus and Manual). The others include throttle response and steering.

But the biggest change is underneath, where it picks up the core of the SL’s upgrade, including an aluminium-based chassis that’s 110kg lighter than the.

Where the SL 500 gets Active Body Control (steer clear of it, if you’re in the market) or steel springs (better), the SL 63 has AMG’s own sports suspension, which takes ABC and AMG-izes it. It’s supposed to have more negative camber than the SL, along with stiffer damping and better dynamics.

The SL’s much-maligned variable rate electro-mechanical steering has gone, replaced by a fixed (and sharper-) rate electro-mechanical setup. It has three-stage stability control, too, while you can spend more for a more-sporty suspension setup and a locking diff.

The standard anchors are a composite of aluminium hats and cast-iron rotors, boosted to 390mm x 36mm, with six-piston front calipers, while 360mm x 26mm solid discs and single-piston calipers work the rear end.

The stock rubber is a 255/35 R19 up front with a 285/30 R19 at the back, and AMG honchos admitted the steering system (which relies heavily on detailed electronic mapping for its feedback and tuning) works best with this stock setup, especially on Continental rubber.

On the optional up-rated gear (255/35 R19 up front combined with 285/30 R20 rears), it’s not so convincing.

PACKAGING

It’s a spacious cabin, with useful storage spaces behind the front seats and in the console, but the marketing guys had some wins in critical areas. The most obvious of these is the siting of the cup holders, right where intuition suggests the gear lever and system control knobs and buttons should be.

There are other disappointments, including the carry over of the old SL’s now-clunky ventilation system, which is now 11 years old.

COMPETITORS

Its predecessor handled so well, without compromising its ride, that people quite reasonably cross-shopped it with far-more serious sports car stuff. That won’t happen anymore. Besides, one of its obvious foes, the Porsche 911, doesn’t have a convertible yet and, even when it does, it won’t have the sort of straight-line urge the SL 63 offers.

Another former rival, the Aston Martin DB9, is trending towards ancient.

You can stretch up in athleticism to things like the Audi R8 V8 and V10, or the Lamborghini Gallardo or the Ferrari California if you like, but they’re not the same style of machine. Something like an M6 Cabrio is more the style, but the BMW is a bit beneath the SL’s traditional heartland.

It didn’t.

Our first taste of the SL 63 was with the bigger rear boots attached and the Performance Pack’s gruntier smokehouse lurking up front. And, by jingoes, does it hammer. It’s relatively quite when you fire it up in Comfort mode, but it gets louder, quick, in Sport and Sport +. It’s a deep, rumbling V8 more in keeping with the SL 55 and the old 6.2, but the turbos muffle it when you crank it hard.

And you will want to crank it hard, because that’s what it was born to do. And it does it stupendously well.

It doesn’t lift and drop revs like a typical turbocharged engine. It feels like a naturally aspirated motor as you pop neutral, cruising through the St Tropez streets to give the appreciative workers a snapping blip on the noise, shaking the windows they’ve just fitted.

There is a launch control fitted to the system, too. It’s nasty. Dial up the revs to a surprisingly low figure (around the 2000 mark is plenty) and it bites, spits, attempts to snap sideways and bites again, blistering hard on its rear air springs and bellowing off the scenery.

And it’s fast. AMG claims 4.2 seconds to 100km/h and if it’s any slower than that, it sure doesn’t feel it. The thing is a jet. The only moderate disappointment is that it doesn’t rev higher, preferring to shift up around 6000rpm or stretching to a 6500rpm limit if you use manual mode. But it’s only a moderate disappointment and you can forgive it many a sin for this engine alone.

It’s smooth too, without a hint of tremor and the turbos can’t be heard either, regardless of how much air they’re cramming into unfeasibly small spaces. But it works from any rpm and it’s never wrong-footed by a bad gearshift. It is just as happy – and nearly as effective – firing on full throttle from 1500rpm as it is from 5000.

It’s hampered, though, by a gearbox that’s hopefully nearing the end of its life. There are hints that this is the last time we’ll see this seven-speed unit in a new AMG and, to be fair, the stop-gap measure of sticking a clutch pack on the back of the seven-speed Benz unit has surprised even AMG with its effectiveness.

But we regularly caught our SL 63 out demanding upshifts a full thousand revs shy of the limiter, so long did the messages take to get through to the gearbox brain. AMG claims it will shift in 100 milliseconds, but that’s a purely mechanical engagement number and seems to discount the seconds our thing took to get the message from paddle to gearbox in the first place.

It’s odd, because the gear-shift paddles are, effectively, light switches and the light switches in my house work in a pretty instant kinda way.

It was the same with its downshifts, which left us constantly flicking at the left paddle in the hope of grabbing a lower gear whenever we attacked into a corner, but the message seemed awfully slow in delivery.

To be fair, on the standard (i.e: no Performance Pack) version we drove the next day, this problem didn’t reoccur and the thing whipped up gears much quicker and blipped and roared down again like a champ, but not like a super-smooth champ. Just a more-predictable champ.

There are issues with the gearbox unit in light-throttle settings and it can be caught out in mid-throttle take-offs and it’s just not smooth. AMG knows this and it’s hanging on as best it can. It did think it had a double-clutch gearbox all lined up a couple of years ago, but they didn’t it passed muster (instead, that unit now lurks inside the Ferrari California and 458 Italia).

But if the SL-AMG fulfills most of its promises in a straight line, a sportscar’s life isn’t all about straight lines. Its predecessor might have been 125kg heavier, but it didn’t feel it. This one, in corners, feels just strange.

Admittedly, it’s better on the smaller wheels and tyres and, as the boffins admit, on the Continental rubber. The issue, according to AMG, is that electro-mechanical steering systems require enormous and accurate mapping to achieve accuracy and feedback and weighting that competes with full mechanical systems, which makes them incredibly sensitive to whatever tyres are under the car. And they’ve not yet done the mapping for the optional, bigger boots…

They’re sure to get it done before the SL 63 gets to the Australian market, because it feels pretty ordinary right now on the Michelins we tested.

It didn’t matter how many miles we logged, it still demanded two or three bites at any corner, especially the front half of a corner. Part of this was the new rack ratio, because it’s much faster than the SL500’s system, but partly because the front end has zero feedback.

It’s almost like turning a spoon in a cup of tea, except that if you turn a spoon hard enough, you find some resistance. Not so here, even on the mapped rubber.

It just ends up feeling a lot lighter than you expect out of a car this big and heavy – it’s 1845kg, after all. True, they’ve done too good a job of disguising the heftbut in doing so the SL might as well be a glorified, two-seat, convertible version of the S-Class (albeit a very fast S-Class) rather than a successor to the old SL 55 or the old SL 63.

To be fair, it rides well. And it’s got plenty of grip beneath it all. And its safety systems mean it’s hugely trustworthy. And all the computer tests AMG has done prove it’s dynamically better than its predecessors. It just doesn’t feel like it.

For that sort of driving, AMG wants you to go upstairs to the SLS. For apart from that cracking engine note, you’re not going to feel like a driving god in the SL 63 anymore.

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