Of course we expected an AMG to join the line-ups of most of the Mercedes-Benz range, but one so soon after the launch of the CLS-Class was unexpected. AMG also hinted that models positioned below the C-Class would receive its special treatment in future.
The styling of the new CLS might seem a little too loud and sporty in basic CLS350 form, but it’s just perfect as a CLS63. The extra bulges and contouring work well with the car’s lowered, widened stance.
The entire suspension system was comprehensively retooled – the front air springs were replaced by a set of steel springs, while the rear end retains the original Airmatic suspension but with revised AMG settings. AMG replaced the original components and control arms with its own, which widened the front track by 24mm. More negative camber was dialled into the front end to enhance grip and reduce understeer in corners.
AMG’s retention of the Airmatic suspension at the rear allows for ride levelling to compensate for any extra load in the boot or on the back seat. The dynamics are a function of AMG Ride Control, which instantly varies the damper settings of the sports suspension. There are, of course, user settings for the dampers, either directly via a button marked with the damper icon or indirectly through the AMG Drive Unit, which tailors the ride according to Comfort, Sport or Sport Plus. Each mode alters the steering, engine and transmission responses, too.
At the heart of every AMG car is the AMG engine, each hand-assembled by a single technician. This new V8 unit adds to the naming confusion because it is still badged as “CLS63”, but the powerplant is actually a 5.5-litre V8, and it isn’t the same one as in the previous CLS55. It is bi-turboed to deliver performance exceeding that of the outgoing CLS63 (which has a 514bhp naturally aspirated V8). Output reaches 525bhp and 700Nm of torque in standard spec, with the highly recommended “Performance Package” option boosting the figures to 557bhp and a massive 800Nm.
The corresponding 0-100km/h timing improves in 0.1-second increments. The outgoing CLS63 manages the benchmark sprint in 4.5 seconds, the new CLS63 drops this to 4.4 seconds, and this goes down to 4.3 seconds with the Performance Package. These seem like small improvements on paper, but on the road the acceleration improvement is quite obvious, especially with the up-specced engine that adds 32bhp and 100Nm to the total tally. This is because the extra torque is spread throughout the engine’s power band, making the added punch felt when one floors the accelerator.
Overtaking is now ridiculously easy – just ensure a clear road ahead, then open the throttle. As this is still a traditional automatic, the gearchanges down the ’box are not sequential. Indeed, the gearbox will drop a few gears at a time for instantaneous kickdown. The AMG’s epicyclic transmission shifts in 100 milliseconds or less, equalling DCT or F1-type gearboxes in shift speeds.
There are the ubiquitous paddle shifters for manual override, and the transmission is near-flawless in auto mode. This characteristic is made possible by the fact that Mercedes AMG models always depend on massive torque from superior engine displacement rather than on high-rpm power like some competitors. This results in a less frenzied driving experience, yet it still delivers storming performance.
This turbocharged CLS63 has a narrower power band than its naturally aspirated predecessor, being redlined at 6400rpm instead of 7400rpm. However, thanks to its twin turbochargers, the 5.5-litre V8 (with the Performance Package) behaves more like a 7-litre engine and easily shades the 630Nm of its forebear. In fact, this new turbocharged engine behaves like the old CLS55’s supercharged V8 in terms of throttle response and power delivery, but without the parasitic load of a whirling supercharger running off the crank.
The 32bhp increase in horsepower is accompanied by a 32 per cent reduction in fuel consumption to 10.1km per litre. This mega-Merc drinks gas like a 2-litre saloon. Amazingly, AMG engineers claim that the car’s fuel efficiency is unaffected by the Performance Package. Still, drive the CLS63 enthusiastically, and its economy will most certainly take a dive.
Vocally, the V8 is pretty toned down, thanks to the two turbos residing in the exhaust pathway. But the powerplant still plays an angry staccato beat as it charges up to the redline.
With the boost set at 1.3 bar rather than the standard 1 bar, the Performance option delivers 800Nm of torque, appearing at just 2000rpm and taxing the traction control at every step-off. This is not Race Start (AMG-speak for launch control), but merely an exuberant full-bore take-off from the traffic lights, with the little traction warning lamp blinking away. This makes the actual Race Start function seem superfluous, as just flooring the loud pedal elicits nearly the same excitement without the forethought required to perform a proper Race Start.
The sequence is complicated, to say the least. First, you need to find the button to activate the ESP Sports setting, and then press the brake pedal with your left foot. Having preselected the Race Start feature by setting the rotary dial to “RS”, a confirmation message now appears on the AMG central display. You need to reconfirm by pulling the “up” shift paddle just once. Now, fully depress the accelerator and quickly take your left foot off from the brake pedal.
The CLS63 will burn some expensive rubber as it scampers to 100km/h in 4.3 seconds. If you looked up at the traffic lights while doing the Race Start procedure, you would have noticed them turning green before you’d activated the RS mode. But as mentioned earlier, there is an easier way to do this – just floor the power pedal and go.
While the Race Start feature seems like a cruel joke, the rest of the car’s intent is deadly serious. The “Comfort” efficiency setting is meant for the wife, or when motoring about in town. The steering is a tad light, although still direct, and the dampers soften up to absorb more bumps at the expense of hard driving dynamics. In this “C” mode, the CLS63 behaves like the CLS500 with its almost flawless street manners – almost, because there’s a small but noticeable point of engagement during the initial move-off from standstill. But once the transmission is “hooked up” fully, it runs as smoothly as any traditional automatic.
AMG tradition is maintained by the rabid way in which the CLS63 launches forward. Opening the throttle pedal wide opens the floodgates to what is a veritable mountain of torque. In the previous CLS55 with 700Nm, one could sense the mechanical innards struggling to cope with the enormous twisting force. But there’s no such “problem” in the new CLS63, which delivers and handles its 800Nm effortlessly. Overtaking in the super-CLS is its crowning glory, putting away all manner of lesser machines as it slingshots past them.
Believe it or not, we found some almost European-like mountain roads in the San Bernardino mountains of our California test route. The car’s “C” setting is out of its depth here, so we switch to the Sport setting and leave the stability control system in its normal mode. With this configuration, the CLS63 is so capable and benign that it begins to feel a tad uninteresting. It seems the ESP always gives the car a safe, mild-understeer attitude no matter what the driver is doing with the steering and throttle. Undoubtedly, the limits are really high and ultimately safe in this “nanny” mode, but it defeats the point of such a high-performance vehicle.
The trick is to put the ESP into Sport-Handling mode. This keeps the electronic guardian away from the goings-on until the last moment, by which time the rears are drifting out a bit. Here, you will find both safety and entertainment. One can turn off the ESP, of course, but it’ll come back on when you hit the brakes. Leave it in Sport-Handling mode and the chassis really shows its stuff, moving around between mild understeer and mild oversteer but always telling you what is happening and providing feedback progressively.
Mercedes has come under a bit of flak for equipping the latest CLS range with electro-mechanical power steering, as it’s short on real feel. For the CLS63, AMG engineers cleverly specified a reduced level of assistance once you select the Sport setting. This makes the steering a bit heftier and marginally more informative.
The Airmatic front suspension was swopped for a set of steel-sprung struts and dampers to heighten handling accuracy and steering directness, and AMG gets full marks for this. However, it also means that ride comfort over expansion joints and potholes is not as good as afforded by the pure air suspension in the plush CLS500. But surely you would not buy the CLS63 for cruising comfort in the city.
All in all, the new CLS63 AMG is hugely accomplished at blending hardcore muscle car fun with day-to-day functionality. The marketing people at Mercedes-Benz have really exploited this niche, which will be the CLS63’s hunting ground until the competition responds with their contenders. The last two AMG CLS models were impressive in their respective debuts, and this new one has kept to the script.
Mercedes-Benz CLS63 AMG 5.5 (A)
ENGINE 5461cc, 32-valves, V8, turbocharged
MAX POWER 525bhp at 5250rpm
MAX TORQUE 700Nm at 1750-5000rpm
GEARBOX 7-speed automatic with manual select
0-100KM/H 4.4 seconds
TOP SPEED 250km/h (governed)
PRICE INCL. COE To be advised (as of March 2011)
Check out the successor to the Mercedes-Benz CLS63 AMG, the Mercedes-AMG CLS53 4Matic