Mercedes SLS AMG Black Series Debuts

Mercedes SLS AMG Black Series Debuts

Just the Facts:
  • AMG claims its fifth Black Series model will bring the handling package of its SLS GT3 racecar onto the road.
  • The standard SLS Coupe's 6.2-liter V8 has been tweaked to peak at 622 horsepower.
  • Top speed is 196 mph.

AFFALTERBACH, Germany — The fastest Mercedes-Benz-badged car in the world is about to get a whole lot hotter. And more expensive.

With the paint still wet on its SLS GT, AMG is showing the world the even faster, even angrier SLS Black Series.

With more power, less weight, tauter handling and, bizarrely, a lower top speed, AMG claims its fifth Black Series model will bring the handling package of its SLS GT3 racecar onto the road.

Another 59 horsepower has been tickled out of the 6.2-liter V8 relative to the standard SLS to peak at 622 hp, a figure that is also 39 hp upstream of the just-released SLS GT. Weighing in at 3,417 pounds, the Black Series process has slashed 154 pounds from the standard SLS AMG.

AMG combines this with an upgraded version of its seven-speed paddle-shift transmission, a coil-over suspension system, carbon-ceramic brakes, stickier tires and an electronically locking differential to create one of the most potent rear-wheel-drive cars it's ever built.

It results in a snarling, snorting monster that tops out at 196 mph, but AMG insists the SLS Black Series does its best work in corners. It also has a shorter final-drive ratio than the standard SLS or the SLS GT (which explains its slightly slower top speed).

It features wider, more aggressive bodywork, bigger air intakes, darkened headlights, deep front and rear undertrays, a massive air outlet carved into the hood and a large rear diffuser. For those who aren't so concerned with elegance, there's also the option of a huge, race-bred rear wing.

The already lean internals of the all-alloy V8 have been overhauled, with a new valvetrain comprising more aggressive camshafts and motorsports-style lightweight bucket tappets.

A freer breathing intake tract helps the engine's maximum speed jump from 7,200 rpm to a more racelike 8,000 rpm. However, the Black Series pays a price in peak torque, which not only falls from the SLS GT's 479 pound-feet to 468 lb-ft, but arrives 750 rpm later in the rev range, too.

The Black Series AMG's bottom end has also been modified. Larger-diameter oil galleys have been drilled in the crankshaft, and new bearings and stronger connecting rod bolts have been fitted to cope with the higher peak engine pressures. The entire oil and water pumping systems are upgraded, including a new oil pump.

But the most innovative change to the engine is actually outside the block, with AMG adding a gas strut brace between the engine and the body to stop it from moving under load changes. On a racetrack, this system is supposed to stiffen or slacken to compensate for "undesired load change reactions in highly dynamic driving on the racetrack," according to AMG Development Boss Tobias Moers.

Oddly, though, while the repowered SLS Black Series is the most powerful normally aspirated car AMG has ever built, it's not the most powerful car on AMG's books. Its 622 hp looks astonishing until you consider that the electric version of the SLS cranks out 740 hp and 738 lb-ft of torque.

The search for performance doesn't end at the Black Series' exhaust manifold, either. AMG has developed a titanium exhaust for the Black Series that weighs just 37 pounds, cutting just over 28 pounds from the old steel system. It has mufflers in the center and at the rear of the car and uses fan-type exhaust pipes for less backpressure and improved responsiveness.

AMG has also taken extraordinary steps to help the handling, including lowering its seven-speed DCT transmission nearly 0.5 inch into the chassis and integrating smaller versions of the engine's gas strut to keep the gearbox locked in place regardless of the torque load on it.

Oddly, though, the Black Series transmission spreads its expertise across Comfort, Sport, Sport+ and Manual modes, even though the just-launched (and supposedly softer) SLS GT has dumped the Comfort setting altogether.

Nevertheless, the Black Series adopts the software developed for the SLS GT to cut its shift times to 60 milliseconds and introduces a double-declutching function for more aggressive downshifts. Not that the SLS has ever suffered from subtlety, but there's now an enormous blip on the throttle when changing down in Sport or Manual modes. It also has a new (and somewhat belated) "temporary manual" mode, so the driver can just pluck a shift paddle to change gear, even if the car is in one of its automatic modes.

One key to the improved performance is a shorter final-drive ratio, though some might find it odd that AMG has replaced the SLS's standard mechanical limited-slip diff with an electronic diff lock. Integrated into the transaxle unit, the newly developed unit can alter the torque bias ratio in acceleration and deceleration, and has more sensitive electronics than any system of its type.

The Black Series still rides on aluminium double wishbones all around, but that's about where its similarities to the standard car end. The hunt for better track performance resulted in revisions to the AMG Ride Control electronically variable dampers, which are now tauter and have just Sport and Sport+ settings. Adjustable perches for the coil-over springs provide the ability to adjust corner weighting and ride height for individual circuits or conditions.

AMG has stretched the track widths of the SLS by 0.78 inch at the front and 0.94 inch at the rear to increase grip, and it has stiffened the suspension bushings by 50 percent on the front axle and 42 percent on the rear.

Upgraded 10-spoke alloy wheels — 19-by-10 inches at the front and 20-by-12 inches at the rear — save the SLS Black Series almost 9 pounds in total. There's also a new front stabilizer bar and new front wheel carriers and revisions to the steering. It wears all-new Michelin Pilot Sport Cup 2 tires measuring 275/35R19 at the front and 325/30R20 at the back.

Inside the lighter wheels sits a monster set of carbon-ceramic rotors, stretching out to 15.8 inches at the front and 14.2 inches at the back. The ventilated rotors are harder than the optional carbon-ceramic brakes on the standard SLS and, at 35 pounds lighter than the conventional brakes, save around 40 percent in weight.

The weight cull has affected everything from the hood to the small panel behind the seats and the diagonal underbody braces. The torque tube that links the engine to the rear-mounted transaxle is now carbon-fiber, and is 29.3 pounds lighter than the 58.6-pound cast-aluminum standard part. The carbon-fiber-reinforced plastic drive shaft inside the torque tube is only 10.3 pounds.

Even the conventional battery has been thrown out and replaced by a lightweight lithium-ion unit, saving more than 17 pounds.

The cabin has also contributed to the lower weight, with AMG sport seats cutting 33 pounds from the standard electric units. Ditching the COMAND navigation and entertainment system has saved another 13 pounds.

Edmunds says: More power, less weight. That's all we needed to hear.

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