Alistair Weaver, VP of Editorial and Editor-in-Chief
"Nobody really cares about horsepower anymore, or the 0-60-mph times," says Tobias Moers, AMG's director of vehicle development. "That is gone and in the past." Today's customers, reckons Moers, are more interested in the driving experience than outright performance.
The days when AMG would simply shoehorn a large engine under the hood of a standard car are gone. Today, only a total vehicle concept will suffice. The 2009 Mercedes-Benz SL63 AMG is the reply to this new set of priorities.
We saw this revised philosophy in the critically acclaimed 2008 Mercedes-Benz C63 AMG, but it's been taken a stage further with the new 2009 Mercedes-Benz SL63 AMG. This car is much more than a face-lifted version of the previous Mercedes-Benz SL55 AMG; the 2009 Mercedes-Benz SL63 AMG is arguably the most ambitious car AMG has built to date.
The Philosophy of Power
For all the talk of a new beginning, the engine remains the focal point of any AMG. Peep under the hood of the 2009 Mercedes-Benz SL63 AMG and you'll find the naturally aspirated V8 used in almost every current AMG model. AMG calls this engine a 6.3 to pay tribute to the famous 6.3-liter Mercedes-Benz V8 that propelled an AMG-built Mercedes-Benz 300SEL 6.3 to 2nd overall at the 1971 Spa 24 Hours, a performance that established AMG's professional reputation. Of course, let us remind you that the new engine displaces just 6,208cc.
The AMG-engineered 6.2 V8 replaces the supercharged 5.5-liter Mercedes-Benz V8 of the Mercedes-Benz SL55 AMG. This naturally aspirated V8 is meant to express AMG's unique engineering capability. It's one of the highest-revving, large-displacement engines in a production car, and the combination of 6.2 liters and a redline of 7,200 rpm offsets the loss of forced induction.
For the record, the AMG 6.2-liter V8 develops 518 horsepower at 6,800 rpm and 465 pound-feet of torque at 5,200 rpm in the SL63. "This is as far as we need to go," says Moers. "It would be almost impossible to cool the engine of a normal road car that developed 800 hp. It's not necessary."
Plenty of Speeds, All Forward
Just as significant as the SL63's V8 is the seven-speed AMG Speedshift MCT transmission, which debuts here. MCT stands for "Multi-Clutch Technology" and replaces the former seven-speed automatic's torque converter. The new MCT incorporates a wet-clutch system in which a series of clutches (six in total) allows for the preselection of different gears.
There are four shift programs — Comfort, Sport, Sport Plus and Manual — with increasingly rapid shift times. In manual mode, the SL will swap cogs in just 100 milliseconds, as fast as the single-clutch automated manual transmission used in the Ferrari 599 GTB Fiorano. Gears are selected using either the paddles mounted on the steering wheel or via the traditional Mercedes lever on the center console.
The new transmission also features a Race Start function. Once you select Sport Plus, you place your left foot on the brake pedal and your right on the throttle. The car then decides the optimum engine speed for take-off before you launch the car at the horizon. It's great for the stoplight grand prix, even if it doesn't do much for the driver's skill set.
A New Animal
Let's cut to the chase. The 2009 Mercedes-Benz SL63 AMG is a quantum leap forward from the old supercharged SL55. Where the SL55 felt like just a faster version of the standard SL, the SL63 feels like a totally different animal. The sound, for example, is nothing less than riotous. Blip the throttle at a standstill and the exhaust crackles angrily. It's sensational, as if this engine has been tuned by people who spend their weekends watching V8 racecars. (Almost true, as AMG is involved with the creation of the Mercedes-Benz racing cars for the DTM series.)
The V8's throttle response is urgent without being nervous. And the new MCT transmission makes this arguably even easier to drive at low speed than the SL55 with its automatic because you don't have a build-up of inertia in the torque converter. Nor do you have the snatchy drivetrain issues associated with a single-clutch automated manual transmission. In the end, a judicious right foot is rewarded with an appropriate response.
This normally aspirated V8 lacks a little of the low-down pull of the supercharged 5.5-liter V8, but it still produces a mighty rapid package. Mercedes claims the 2009 Mercedes-Benz SL63 will accelerate to 100 km/h (62 mph) in 4.6 seconds, with an electronically limited top speed of 155 mph. And the more free-revving nature of this engine seems to suit the SL63's more focused, aggressive nature.
This revised nature is also due in no small part to the gearbox. Pop it into the fully automatic Comfort mode and it makes a fine impression of a conventional automatic. Only occasionally, such as when slowing to a stop, do you feel a subtle jolt that serves as a reminder that there's no torque converter to smooth the transition between gears.
Turn the rotary knob to select Sport Plus or Manual, though, and you have a gearbox that will riffle through the cogs as fast as any on the market. It's much smoother than the former single-clutch SMG system found in the BMW M6, and downshifts are accompanied by an automatic blip of the throttle and a sonorous cry from the V8's exhausts.
Keep Your Body Under Control
As before, the 2009 Mercedes SL features Mercedes-Benz's Active Body Control (ABC), and there are two settings to choose from. Standard delivers a comfortable cruise, while Sport increases the damper rates and reduces the roll. In standard mode, this car rides at least as well as a standard SL and even in Sport, it's never less than comfortable. This might be an AMG-specification SL, but it has none of the harsh, stiff-legged feel of an M6.
Considering it weighs 4,343 pounds, the SL63 feels remarkably agile. Indeed, it feels more like the smaller, lighter SLK than a boulevard cruiser favored by those of advancing years. The grip is prodigious, the steering nicely weighted and communicative, and the brake pedal is tuned for easy modulation. You had to guide the old SL55 AMG, but you can hustle the SL63 AMG.
It's also good to report that for the first time on a modern SL, you can completely switch off the electronic stability control which allows the driver to perform massive tire smoking burnouts. Actually the system has three settings: Normal, Sport (with a higher threshold of intervention) and Off.
The styling of the newly revised Mercedes-Benz SL lends itself well to the AMG makeover. The whole car has been made much more aggressive and striking, and these changes are enhanced by the AMG styling package. You get a grille of black mesh, a bold new chin spoiler, side skirts, a trunk lid spoiler and a black diffuser at the rear, plus great-looking 19-inch aluminium wheels.
At the same time, opinions are also divided about the overall success of the restyled Mercedes SL. It certainly has more impact and it looks better on the road than it does on the show stand, but some of the elegance of the old model has been lost. And the rear aero diffuser of the AMG package doesn't help, as it seems awfully like an aftermarket piece, while the AMG engineers don't even pretend that it serves an aerodynamic purpose.
Inside the cabin, the AMG-equipped SL features carbon-fiber trim, AMG instrument dials (including a lap timer) and sport seats with AMG upholstery. The interior is comfortable and spacious, but some of the details seem a little inconsistent with the quality this car wants to project.
For customers looking to personalize their cars further, AMG is offering a Performance Studio package that includes carbon-fiber exterior details, different wheels and a new steering wheel. There's also an optional Performance Package includes a limited-slip differential, revised suspension, uprated brakes, lighter 19-inch forged wheels different wheels and of course a new steering wheel. The $14,070 option also raises the cars computer limited top speed from 155 mph to 186 mph.
Choose Your SL
The 2009 Mercedes-Benz SL63 AMG is not the only AMG version of the recently revised 2009 Mercedes-Benz SL. AMG is also continuing to offer the Mercedes-Benz SL65 AMG with its twin-turbo 6.0-liter V12 rated at 604 hp and 738 lb-ft of torque. Mechanically, this car is unchanged. It's more refined and ultimately faster than the SL63, but less satisfying to drive. Even AMG's own management accepts that the SL65 exists primarily to satiate the desires of customers who simply must have the fastest and the most expensive.
By contrast, the 2009 Mercedes-Benz SL63 AMG will appeal to an enthusiast who appreciates a broad range of abilities in his motor car. It is happy to play the grand touring role in the best SL tradition, but it's now also a much more effective performance tool with an impressive range of attributes. Ever since the AMG 6.3 V8 was introduced, AMG has been busily making over its line of Benzes in the engine's 500-hp image, and the result is not only a watershed in AMG's performance philosophy, but also a dramatic change in the personality of the Mercedes-Benz SL.
Edmunds attended a manufacturer-sponsored event, to which selected members of the press were invited, to facilitate this report.
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