Mercedes-Benz SLS AMG
Debut: 2009 |
||||||||||||||||
From 2003 to 2009, Mercedes-McLaren built about 2,100 units of SLR, making it the highest selling supercar ever made. However, the SLR has never got the admiration Mercedes expected. People criticized its excess weight, stiff ride, numb steering and brake. No one regarded it as great as contemporary supercars like Porsche Carrera GT, Ferrari Enzo or Bugatti Veyron, and most prefer to drive a (much cheaper) Ferrari 599 GTB instead. It's no secret that the Anglo-German partnership has never been a happy memory to both parties. Although they did not blame each other openly, they thought they could do much better had they went on their own. Eventually, they broke up – both in F1 and road car – and started their own ventures. On September 8th, 2009, McLaren unveiled its own supercar, MP4-12C, to the public. Interestingly, in less than 24 hours, Mercedes responded with its new SLS supercar. The SLS is the first car developed by AMG division from ground up, rather than modified from Mercedes' mainstream models. Costing an estimated £150,000, it will compete with the McLaren supercar as well as established rivals like Ferrari 458 Italia, Lamborghini Gallardo LP560-4, Porsche 911 GT2 and Audi R8 V10. However, I suppose most comparison will be drawn with the new McLaren. Now both companies are given full freedom to design their cars, which one will be better? We won't get the answer until the McLaren goes on sale in 2011, but right now the Mercedes supercar is available for our evaluation.
At first glance, the SLS does not look like a proper supercar. This is because it has an ancient appearance deliberately resembling the 1950s 300SL Gullwing, which is still the definitive Mercedes sports car until today. It has a big mouth, followed by a long long bonnet, an upright windscreen and a small cockpit that sits near the rear axle. This profile speaks little about speed and aerodynamic efficiency. Moreover, its low, sloping tail clearly works against the requirement for downforce, so it needs a retractable rear spoiler to provide the necessary stability at speed. Modern aerodynamics usually shape supercars like wedges. In contrast, the SLS looks like a big German sausage, especially in red. This is easily one of the most distinctive cars in the world since Weinermobile. A beauty it may not be, but the SLS is unquestionably very well engineered. Its wide and long-wheelbase chassis is constructed entirely from aluminum, i.e. extrusions, castings and pressed sheets, as are the outer body panels. Lacking carbon fiber in its construction does not prevent it from undercutting SLR on the scale – at 1620 kg with fuel and coolant, it is between 30 and 70 kilograms lighter than its carbon-fiber predecessor, although you may say Ferrari 458 and Lamborghini Gallardo are lighter still.
The AMG chassis is also very well balanced - or indeed perfectly balanced - with 47:53 weight distribution front to rear. This is easily understandable when you see its engineering drawing. The whole engine is mounted well behind the front axle (that explains why the bonnet is so long) and counter-balanced by a transaxle mounted at the rear axle. Linking between them is a strong aluminum torque tube, inside which a lightweight carbon-fiber drive shaft is spinning at engine speed to drive the gearbox and rear wheels. This arrangement can be seen in every front-engined Ferrari or manual-box Maserati. It goes without saying that it delivers excellent balance and low polar moment of inertia. Worth noting is that, unlike Ferrari or Maserati, AMG puts the gearbox aft of the rear axle in order to achieve the rear-biased weight distribution. This theoretically increases its polar moment of inertia a bit. Compared to SLR, the biggest advancement of SLS is probably its gearbox. Here comes a modern 7-speed dual-clutch gearbox, versus the outgoing 5-speed automatic. It compensates the reduced torque output of the naturally aspirated engine with its closer ratios and far quicker gearshift. The gearbox is supplied by Getrag based on the one debuted in Ferrari California. About 70 percent of its components are common to the Ferrari's, but the ratios and program are unique to AMG.
At first, I was a little bit disappointed to hear that the SLS engine is again that AMG 6.3-liter V8. You know, these days there are no less than eight AMG models employ this engine, including the entry-level C63 and the mud-on-your-face ML63. It sounds not exotic enough for AMG's flagship supercar, doesn't it ? Think twice, however, there seems to be nothing wrong. We always regard the 6208 cc V8 as one of the world's best engines. It has great horsepower, great torque and great sound to shut up the unbelievers. Moreover, the new version codenamed M159 (instead of M156 in other AMG models) has undergone considerable improvements. Now the V8 is converted to dry-sump lubrication in order to lower its center of gravity. Its intake manifolds, intake ports and exhaust are modified to enhance breathing, while hotter cams and valvetrain, lighter forged pistons and stronger crankshaft also contribute to extra power. The result is 571 horsepower at 6800 rpm, 46 ponies higher than the most powerful version of its siblings. Maximum torque inches up 14 pound-feet to 479 lb-ft, and appears earlier at 4750 rpm instead of 5200 rpm. This makes the SLS slightly more powerful than rivals 458 Italia and Gallardo, and significantly more torquey than them. It is not as powerful as the V12-powered 599 GTB though, but it has more twisting force to haul a lighter body, so theoretically its performance should be comparable to the flagship Ferrari GT.
Then how fast is it ? AMG claims it can sprint from 0-60 mph in 3.7 seconds if you activate the "Race Start" gearbox mode. That rests on the same level as the outgoing SLR and the absurdly expensive Lexus LF-A. However, if the manufacturer's figure is accurate, it won't be as quick as Ferrari 458 and 599 in straight line acceleration. These Ferraris utilize their ultra-responsive gearbox and sophisticated traction control to achieve 0-60 in the range of 3.2 to 3.4 seconds, and 0-124 mph in less than 11 seconds. The latter is 1 full second quicker than the AMG. They can also easily crack into the 200 mph barrier. Strangely, AMG claims SLS is "electronically regulated" to 197 mph, some 12 mph slower than the outgoing SLR 722, so it won't be the fastest Mercedes-Benz road car in history. I suspect even with regulator disabled, its top speed would be much the same due to its poor aerodynamic drag of 0.36. Adding speed regulation is just a way to save its face. Other aspects of the car are quite conventional. Its suspensions are all-round aluminum double-wishbones with fixed rate dampers. Standard stoppers are large steel brakes (390mm discs and 6-pot calipers up front, 360mm discs and 4-pot calipers at the rear), while ceramic brakes are optional. The AMG design wheels are 19-inch and 20-inch front and rear respectively. They wear Continental high-performance tires measuring 265/35 and 295/30 respectively. Electronics are simpler than Ferrari's. You get ABS, ESP and four choices of transmission mode (including the aforementioned "Race Start" launch control), but it lacks an integrated chassis control system, or the ability to alter suspension or differential setting, because both are passive devices.
On the Road Visually, the SLS is the most beautiful when it is parked stationary and has its gullwing doors opened. In this form, few cars can cause as much sensation. The original 300SL adopted gullwing doors because of its unusually wide sills, which required the driver to climb from above, hence the need of opening part of the roof. The new car's sills are much narrower. You sit on the sill, thread your legs into the footwell and drop yourself into the deep bucket seat. Now you may wonder how to close the door. Mercedes should have installed power doors, but for weight saving it didn't, so you will need to climb back to the sill, grab the door handle and close the door while dropping into the seat. Fortunately, the aluminum doors are fairly light and easy to close. Once you are in the cockpit, you will find a very snug environment. The dashboard and the upright windscreen are very close to you. There is no space behind the seats, so fore and aft adjustment is limited. People over 6 feet tall may find headroom and legroom tight. Interior storage is limited to a tiny glovebox. The dashboard design is classical, with some chromed gauges and air vents, aluminum or carbon-fiber decors on the center console. You can order red stitched leather to enhance the classical ambience further. Anyway, it doesn't look very like a supercar cabin as it lacks the exotic factor. Visibility is another problem. Forward view is hampered by a long bonnet. Rearward view is better, but the swoopy tail means you can hardly judge its exact location. Parking takes special precaution.
However, all these faults become insignificant when the motor roars into life. Those accustomed to the SLR's supercharged V8 will immediately notice its new found enthusiasm - the throttle response much sharper, the power delivery more linear and the sound more delicious. The bottom-end punch might be softer, but once into 2000 rpm, where 369 lb-ft is available for disposal, it becomes really really strong, and the car accelerates with the urgency you would expect for a junior supercar. Its smoothness and its enthusiasm for rev are remarkable for such a big-capacity V8. As rev rises, the V8 rumble is gradually substituted by a race car thunder towards its 7200 rpm cut-out. Having said that, the AMG V8 is not the best sounding engine in the class. Ferrari's V8, Lamborghini's V10 and Toyota's V10 produce more addictive sound when they approach 8000 or even 9000 rpm. The AMG voice and linear power delivery are also slightly hampered by the 7-speed dual-clutch gearbox. While its smoothness is beyond criticism, the gearchange has noticeable delay compare with the dual-clutch gearboxes on Ferrari or Porsche. Although AMG said its calibration is yet to finalize, I suspect the tremendous torque of its engine may present greater difficulties to quicken its gearchange.
The big surprise is its chassis. AMG cars used to be big on power and weak on chassis. The SLS is totally different. Storm it on a race track, you will be amazed with its great balance and immense stability. The low center of gravity is obvious, as is the incredible stiffness of its chassis and the formidable brakes. You can go very fast and deep into bends without breaking its grip or distorting its neutral attitude. Its steering is swiss-watch accurate, if not as sharp as the helm of Ferrari or as tactile as Porsche's. Being a front-mid-engined machine, its handling is inherently tidier than its mid or rear-engined rivals. You have to be really aggressive to swing it into oversteer. If you succeed to do so, you may discover the raw side of its handling, because the way its tail break loose is sudden and unpredictable. However, on public roads it will be very difficult to approach its limit, especially with the safeguard of ESP. The most impressive of all is its combination of fluid handling and a forgiving ride. The lack of adaptive suspension is compensated with well-judged damping, so the SLS is a terrific long-distance cruiser. In many ways the SLS is a strong rival to Ferrari 599. Ultimately, it is not as sharp or as engaging to drive as the Ferrari. However, it is unquestionably the best sports car Mercedes has ever built, one that easily wash away the unhappy memory of SLR. Well done AMG. |
||||||||||||||||
| The above report was last updated on 21 Dec 2009. All Rights Reserved. |
| AutoZine Rating | ||
 SLS AMG |
| Specifications | ||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||
| Performance
tested by: *Quattroruote,
**C&D, ***R&T, ****Autocar |
Copyright©
1997-2009
by Mark Wan @ AutoZine