2011 Mercedes-Benz SLS AMG
We're flat-out on Germany's Sachsenring race track in the new Mercedes SLS AMG, chassis number 00045, a mildly camouflaged pre-production model. Ahead is an SL65 AMG Black Series--twin-turbo V-12, 670 hp, 738 lb-ft of torque--driven by Tobias Moers, head of AMG's r&d division, seasoned race instructor and today's pace-setter. Filling his mirrors, our red gullwing keeps pushing harder and harder, even though its normally aspirated 6.2-liter V-8 is rated at a comparably modest 571 hp and 479 lb-ft. The Sachsenring has plenty of slow corners, lots of climbs and descents, two long straights and two very fast and very blind fourth-gear bends.
As our session progresses, this track is becoming a nightmare for the wide, fat SL, and dreamland for the light and nimble SLS. Despite the Black Series car's four more cylinders, 100 extra hp and 259 lb-ft of added torque, it's punished by its 551-lb weight penalty. The SLS not only uses a significantly lighter double-wishbone aluminium suspension, it also boasts a featherweight spaceframe body which tips the scales at a mere 531 lbs. Perhaps even more significant is the weight distribution. In contrast to the nose-heavy SL, the new gullwing places only 48 percent of its mass on the front axle and 52 percent on the driven wheels.
In this match, the Black Series SL doesn't stand a chance. It understeers early, and after only ten laps it has practically run out of front tires. The momentum gained on the straights can never compensate the speed lost on the approach to and through the infield.
The SLS is a totally different animal. It is 49 inches low and 76 inches wide, with cab-backward proportions that emphasize the front-mid-engine layout. The boxy light-alloy skin is draped over a long, 105-inch wheelbase. The gullwing doors open at a large 70-degree angle, but even when fully deployed, the maximum clearance is a scalp-threatening 5 feet, so that short people can still reach the inner grab handles from their seats. The power-operated buckets, which feature lightweight magnesium backrests, are comfortable and supportive. The steering wheel's squared off bottom is a bit of a nuisance through the esses, and in a car this sporty, the shift paddles should be attached to the column--not the wheel.
Instead of a conventional transmission lever, the SLS features a small T-handle gear selector. Push it forward to engage reverse, pull it backwards to select drive, hit the button marked P for park. To the left are five buttons marked engine start, transmission mode (controlled efficiency, sport, sport plus, manual), ESP (on, off or sport), rear spoiler (it automatically extends at 75 mph) and AMG (to store your favorite settings). The familiar Comand system controls the various communication, navigation and entertainment functions. Like every AMG car, the SLS offers a choice of in-dash readouts which relay the coolant, engine and gearbox oil temperatures, the current ESP setting and the most recent lap and trip times. Above the two large main round instruments, there is a supplementary digital LED rev counter with one amber warning segment at 6900 rpm and two red warning dots which come on at 7100 and 7200 rpm.
The exterior design of the new gullwing incorporates modern and retro elements. The large grille, the side cooling gills, and the signature doors all mimic the original 1954 silver arrow. The cleverly packaged and neatly finished interior charms with its rather unique cocoon effect provided by the clamshell doors and the extra-tall sills. The cabin feel is snug but by no means claustrophobic. Standard equipment includes keyless ignition, heated seats trimmed in soft Designo leather, parking aids complete with rear-view camera, and lightweight pedals with rubber studs. Extra money buys speakers by Bang & Olufsen, carbon fiber trim, memory seats, a DVD changer, and your choice of multi-hued color schemes with contrasting stitching and piping. This is definitely not your father's Benz.
Thumbs up? Let's go! This time, there is no Black Series lead car. We're on our own now, for eight more hot laps. Time to hit the AMG button and summon the preferred set-up: transmission in sport plus, ESP in sport. There is no choice of setting for the dampers or the steering, the latter of which takes only 2.7 turns from lock to lock. In sport plus, the seven-speed dual clutch transmission swaps the gears with the same brutality as in the Ferrari California, and it also blips the throttle during downshifts. Engine and gearbox are connected via a carbon-fiber torque tube, which distributes the power to the rear wheels via a 100 percent mechanical limited-slip differential.
First gear runs out of revs before you can say "Wow," second is only suitable for the slowest corner of the track, third is a wonderfully elastic ratio which perfectly matches the engine's 4750-rpm torque peak, fourth successfully conquers fear through the two heart-attack left-handers, fifth is just about all you need to reel in the short downhill stretch and the hunchback start-finish straight.
Unlike the tail-happy C63 and the slightly ponderous SL63 we drove to acquaint ourselves with the track, the SLS AMG is so stable and composed, it feels strangely uneventful and uninvolving. How come? Because the new dry sump lubrication helps provide an exceptionally low center of gravity, the transaxle layout ensures an amazingly neutral handling balance, and the staggered-size tires (265/35R19 in the front, 295/30R20 in the back) provide an almost insane amount of grip. As a result, the 3571-lb two-seater is as expressively dynamic in one direction as it is absolutely unshakeable in any other. Although confidence is quickly established, it takes at least half a day--and an eye-opening ride with the former DTM champ Bernd Schneider--to fathom the true potential of this very special Mercedes.
But even then, the prevailing impression is compiled of such pragmatic virtues as compliant ride, accessible performance, perfect balance, enough noise but no undue vibrations or harshness. For a rear-wheel-drive supercar, the SLS is incredibly benign and forgiving.
One key dynamic asset is the steering. Meatier and less damped than in other AMG models, it opens up a new level of man-machine dialogue. It's a precision tool that fuses minimum input and maximum control, even through that adrenalin-pumping 110 mph uphill kink where the coupe's fat rear end wants to play catch and release. Then there's the electronic throttle, which allows you to modulate and time the torque flow to perfection. The free-breathing, high-revving V-8 responds to the driver's right foot like a thoroughbred to the prose of a horse whisperer. Especially in manual mode, where the transmission holds the chosen gear no matter what, the SLS rides the torque surf so expertly that every approach is a trough, every apex is a crest, and every exit is a mighty tidal wave.
To boost the 6.2-liter V-8's power output from 525 hp to 571 hp, AMG developed a new larger-diameter intake plenum, hotter camshafts, a more ambitious lightweight valve train and a low-resistance multiple-pipe exhaust system. Other measures include slimmer forged pistons, reinforced crankshaft bearings, toughened reduced-friction piston liners, a stiffer crankcase, a shorter cooling circuit and a more efficient lubrication. Lighter, torquier and quite a bit more powerful, the tweaked 6.2-liter V-8 actually uses less fuel than the version in the E63 and S63 (though U.S. EPA figures are not yet available). Mercedes is quoting a 0-to-62 mph time 3.8 seconds and a top speed of 197 mph.
Equally impressive are the brakes. One can specify extra-large carbon-ceramic rotors which are immune to high temperatures and offer a 40 percent weight advantage, but even the standard steel discs are very good at neutralizing excess kinetic energy. Despite the commendably short pedal travel, the massive six- and four-pot calipers cover the complete deceleration spectrum from touch-then-go-again to all-anchors-dropped.
No, we don't know yet how the SLS fares on broken pavement, on twisty autobahn sections, or in stop-and-go traffic. If the performance on the track is any indication, the new AMG-Mercedes promises to be one of the true greats.
Look for the SLS to make its public debut at the Frankfurt auto show in September and U.S. sales to start next summer, with production capped at 5000 per year. Next in the five-year cycle of the project is the roadster, which goes on sale in early 2011. Three and a half years later, we are going to see a limited-edition farewell Black Series gullwing. And believe it or not, there is also a zero-emission version in the works for 2012.
Mercedes-Benz SLS AMG - Preliminary Specifications (per manufacturer)
Engine: 6.2-liter, 32-valve DOHC V-8
Power: 563 hp @ 6800 rpm
Torque: 479 lb-ft @ 4750 rpm(7200 rpm max engine speed)
Transmission: 7-speed dual-clutch automatic
Drive: rear-wheel
Wheels: 9.5 x 19 inch front, 11.0 x 20 inch rear
Tire size: 265/35 R19 front, 295/30 R 20 rear
Length: 183 in
Width: 76 in
Wheelbase: 105.5 in
Track front/rear: 66/65 in
Curb weight 3571 lbs
0-62 mph: 3.8 seconds
Top speed: 196 mph
Fuel economy: 18 mpg (city/hwy combined on Euro cycle)
