Mercedes-Benz SLS AMG 2009 Review - International
AMG's first standalone model is a performance standout and already a modern classicMercedes-Benz SLS AMG
Monterey, California USA
What we liked
>> Outstanding engine performance and sound
>> Prodigious grip and idiot-proof handling
>> Classy cabin
Not so much
>> Rear-end styling doesn't quite match frontal aggression
>> DCT response needs to be sharper to match best
>> Stability control could be a touch freer in Sport setting
Overall rating: 3.0/5.0
Engine and Drivetrain: 4.5/5.0
Price, Packaging and Practicality: 3.0/5.0
Safety: 4.0/5.0
Behind the wheel: 4.5/5.0
X-factor: 5.0/5.0
OVERVIEW
-- AMG's first is old made new again
It's a measure of the confidence of Mercedes-Benz in its in-house performance brand, AMG that this car has made it to the road. For in trusting AMG to build its brand's range-topping sportscar as a standalone AMG-only model, the upper echelons of Daimler AG have very publicly anointed the Affalterbach-based operation. To do so at a time when the global economy is still shaky only makes the endorsement even stronger.
In planning since 2005 and finally launched last week in its production-ready form after almost two years of teasers, spy shots and more misinformation than facts, the Mercedes-Benz SLS AMG is AMG's first unique model. Though it shares aspects of its engine with other AMG models -- as well as electrical platforms and ancillaries -- that's essentially the extent of the crossover...
You won't find many C or E 63 components onboard the CLS. Underneath the skin there's an alloy spaceframe chassis, suspension and rear-mounted transaxle-housed dual-clutch automated gearbox that are all purpose-built for the car.
AMG and Benz refrain from calling the SLS a Gullwing officially but they are the only ones. Interestingly, according to AMG insiders, the roof-hinged doors were not on the car from day one. It was only after the car's basic structure was defined that the Mercedes-Benz stylists proposed to the AMG engineering team the adoption of the trademark doors.
Though trumpeted as AMG's own, the SLS is nonetheless still very much a Mercedes. Its styling was the work of the iconic German marque's 'central' design team, tweaked by AMG. And though the engines are hand assembled at Affalterbach, the car itself is built at M-B's main plant at Sindelfingen.
Thus it's hard not to notice that the largest three-pointed star to be fitted to a M-B passenger car takes pride of place on the 300SL-aping grille. And to punctuate the point there's another tri-star on the topside of the front clip just a few centimetres away.
PRICE AND EQUIPMENT
-- If you have to ask...
Just one SLS model will be offered initially -- a two-door, two-seater coupe. There are no engine or gearbox options. In the rarified world of bespoke sportscars this is not uncommon, but it won't be a permanent situation either. Next year AMG will launch a convertible variant of the SLS -- probably at the Geneva show in March (although that could be stretched to later in the year) -- and down the track there will be a Black Series with more performance and, almost certainly, a racetrack ready version to take on the likes of Porsche, Aston Martin and Maserati in the FIA GT series.
The SLS is motivated by AMG's own 6.2-litre naturally aspirated fuel-injected V8 coupled with AMG's new SPEEDSHIFT DCT automated manual dual-clutch seven-speed gearbox. The latter is rear-mounted and shares its alloy casing with the final drive unit -- hence the term transaxle.
An electric E-Drive version has been talked about, although it's not clear whether AMG will build these in any numbers, nor sell it outright. We expect it to be leased to 'owners' in the same way Smart has trialled EV versions of the Fortwo and Honda's its FCX Clarity fuel cell.
The SLS officially went on sale in Germany this month with a pricetag of Euro 177,310 including sales tax. In straight conversion terms that's around A$284,000. With local luxury car taxes, GST and the like, the pricetag is likely to be closer to $500,000 when it arrives sometime next year.
Befitting its role as a rangetopper the SLS is very well equipped, but there will also be a wide range of options available. Standard equipment includes high-end satnav and audio system, multifunction electric seats, cruise control and all the usual mod cons.
The surprisingly spacious cabin is trimmed in rich leather and features real alloy highlights. Those with healthy chequebooks will, however, be able to further option up the interior and exterior with a bevy of carbonfibre trim items as well as special bespoke leather combinations and racetrack-ready sports seats.
Key performance options will include a lowered and slightly stiffer sports suspension set-up (not that the standard damper and spring settings are anything other than firm), a brake upgrade featuring lightweight carbon-ceramic rotors and higher performance calipers and lighter forged alloy ten-spoke wheels.
In standard trim the SLS rides on seven-spoke alloys. Signature AMG twin-element five-spoke alloys and forged ten-spoke alloys will be optional. All wheel sizes are identical -- 9.5 x 19-inch up front and massive 11 x 20-inch at the rear.
The pricing of all the SLS options are still to be confirmed. We'd be surprised if there was any change from $25,000 for the brake upgrade but it's money well spent. While the SLS's standard steel anchors are very good, the ceramic composite jobbies are in another world.
MECHANICAL
-- Alloy wonder
The SLS shares some of its engine architecture with other Affalterbach models, but that's the extent of the componentry transfer. The two-seater features a unique (for AMG and M-B) front/mid-engined layout and a rear-mounted dual-clutch seven-speed gearbox transaxle unit that helps deliver a static 53:47 weight distribution and racecar-like balance.
The twin-clutch automated manual AMG SPEEDSHIFT DCT gearbox is in the same housing as the SLS's mechanical limited slip differential (brake traction control is also used to supplement the LSD). Unlike the SPEEDSHIFT MCT auto transmission fitted to the SL and E 63 models, this is a true manual gearbox. The seven-speeder and transaxle were developed in conjunction with Getrag and share their basic design with the unit featured in Ferrari's California GT. For its use in the SLS, AMG developed bespoke software and settings for the gearbox. It's also beefed up substantially to cope with the SLS's considerable extra power and torque.
At 420kW at 6800rpm and 650Nm at 4700rpm, the hand-built dry-sumped 6.2-litre AMG naturally-aspirated engine is AMG's most powerful yet and wears the designation M159 (the standard 6.2-litre is the M156). It's still 100hp or thereabouts shy of the ballistic biturbo V12 in the SL 65 AMG Black but the SLS in toto is scores of kilograms lighter than the big Black bomber.
AMG claims a power-to-weight ratio of 2.8kg per horsepower for the SLS. That ensures the 1620kg SLS accelerates from 0-100km/h in 3.8 seconds and 0-200km/h in under 12sec. It has an electronically limited top speed of 317km/h.
Weighing in at just over 200kg, the tuneful fuel-injected V8 differs from the engines used in the rest of the AMG 63s by dint of the fact it features a new dry-sump oiling system. It also gets unique forged pistons (saving 500g), new cams with revised timing, a stronger, stiffer crankshaft and other detailed changes including the use of lighter alloy fasteners.
The efficiency of the drivetrain is highlighted by its fuel economy -- at least when it's not being pushed hard at a racetrack. In Euro testing the SLS returns a combined economy figure of just 13.2L/100km.
The engine is mounted lower and further rearwards than would be considered conventional for a front-engined car– thanks to the long-wheelbase, long bonnet and dry sump system. It is bolted to the transaxle unit via a structural alloy torque tube, inside of which a carbonfibre tailshaft spins at crankshaft speed and transfers drive rearwards. Though the layout in part mirrors that used by Nissan in its GT-R, the SLS is resolutely rear-drive only. The ultra compact nature of the V8 installation also does away with the Nissan's step-up gears.
The architecture of the SLS allowed the engineers to maximise the intake efficiency of the high-revving eight. Straight tuned-length induction tracts maximise output. Says AMG's senior powertrain engineer and SLS team leader Dr Martin Hart, the engine is merely "loping" at its current output. There's plenty more to come, it seems.
PACKAGING
Not surprisingly the SLS's aerodynamic numbers are not all that flash. While the latest E-Class sedan can achieve a Prius matching Cd of 0.25, the SLS comes in at around 0.34. Tight packaging ensures an almost flat bottom but there are no aero aids under the car per se.
Under the skin, the structure of the SLS is unique and save for ultra high strength steel in the A-pillars, is almost entirely fashioned from aluminium. The chassis comprises a central spaceframe cockpit constructed using a mix of forged, cast and extruded alloy components, upon which front and rear subassemblies are grafted. Major panels are alloy with the exception of the boot lid which is composite (its complex shape hides a speed-activated pop-up spoiler).
All four corners get double wishbone fully independent suspension with conventional steel spring/damper units. These are not adjustable from the cabin. Wishbones, steering knuckles and hub carriers are all forged alloy.
The SLS's wheelbase of 2680mm places it between the rangy 2750mm of Ferrari's 599GTB and the stubby 2350mm of Porsche's 911 Turbo. Front and rear tracks of 1682 and 1653mm lineball with the Italian (1690/1618) but considerably wider than the German turbo six mentioned above (1515/1550). At 4638mm long the SLS is shorter than the 599 (4665) and longer than the GT2 4469. It's wider than both cars.
Steering is via normal hydraulically assisted speed-sensitive power steering -- albeit with a particularly quick though single ratio rack.
Inside, the two-seater cabin is surprisingly spacious -- in terms of both width and length. A strict two-seater, the cabin easily accommodated the tallest of AMG's invited guests at the car's Laguna Seca launch. There's modest storage available within the car though door pockets aren't the perfect solution in a gullwing set-up.
A simple leather-covered wing-section dashpad runs the width of the cockpit, punctuated only by a classical instrument binnacle that closely traces the instrument panel. The latter comprises of speedo and tacho and central digital information display. Above this a staged shift light lets you know when to bang the next upchange through when in manual max-attack mode.
The SLS's four 'bulls-eye' vents are disappointingly 'plasticky' to touch but the simple centre stack and console with alloy highlights (carbonfibre is optional) is classy. This houses the HVAC, audio, satnav screen and other controls. Benz's excellent COMAND control system is used to control most of the functions.
There's a small T-bar style PRND gearshifter on the console with a push-to-actuate park setting. There's no facility to change gears manually at the shifter; that's all done via the alloy paddles on the electrically-adjustable steering column. Cruise control, audio and information displays are all pure Benz and steering-wheel control or stalk operated.
Also on the centre console are the controls for the SPEEDSHIFT DCT's four modes. A simple dial allows the driver to select a choice of four different driving modes: C (Con-trolled Efficiency), S (Sport), S+ (Sport plus) or M (Manual). In the Sport, Sport plus and Manual modes the throttle blips on downchanges. AMG claims a shift time of 100 milliseconds and has even used special ignition timing maps to simulate the burping and crackling highly tuned engines have on overrun -- this is active in S, S+ and manual modes.
There is also the stop/start button, a button to activate the sports setting or fully disable the SLS's standard stability control. Other buttons are controls for the speed-sensitive rear spoiler and an AMG button. The latter is similar to BMW's M-button and is, we assume, programmable. Truth is we were too busy driving the SLS to spend time on working out how this worked.
Those trademark gullwing doors latch onto a wide sill rail that initially makes entry and exit to the low-set and heavily bolstered seats a little awkward. Once you jumped in and out a few times things got a little easier. There's definitely a knack to the process, including grabbing the door and bringing it down with you if you're a little on the short side. If you forget, the open gullwing door's grab handle is a fair reach up.
AMG used new super-plastic alloy forming techniques to press the trademark Gullwing doors' complex shapes. In a tangible link to the past, experience from original 300SL Gullwing owners is incorporated in the doors' design to ensure industry-best weather sealing, functionality and NVH. Chief Engineer, Dr Frank Emhardt told the Carsales Network. Owners need not fear rainwater puddles.
SAFETY
Extensive safety features include three-point seat belts with belt tensioners and belt force limiters, and eight airbags -- adaptive front air-bags for the driver and passenger, a kneebag for each, two seat-integrated sidebags and two windowbags deploying from the gullwing doors.
The SLS's braking system features the latest suite of antilock and brake effectiveness technologies. Stability control is standard and in ESP Sport mode allows reasonable leeway for enthusiastic drivers to enjoy the drive without completely deserting the safety net of driver aids.
A tyre pressure monitoring system is fitted as standard.
COMPETITORS
In terms of performance and handling prowess, it's cars like the already mentioned Ferrari 599GTB and Porsche 911 GT2 that will be pitted against it. You can add in the Aston V12 Vantage and the Audi R8 V10 while you're at it. In sheer dollar terms there are cars like Bentley's Continental that will also vie for attention.
AMG firmly believes the car will attract new (and blue) blood to the brand. Where perhaps even AMG versions of the SL were too soft for buyers of brands like Lamborghini and Porsche, the SLS should deliver the harder edge these types of buyers crave.
It almost goes without saying the SLS is rapid -- indeed, it's prodigiously quick. What perhaps surprised more is how resolved the car is on both road and track.
On the road the SLS has almost 'unbreachable' levels of grip. You have to be hamfisted or deliberately provocative to get the ESP light anywhere near flashing -- even on fog-dampened roads. Steering feel is a little odd just off centre (the steering goes momentarily light like the car wants to 'fall' into the corner) but then it settles down, weights up and bites. It is a corner carver extraordinaire with ne'er a hint of body roll and nothing of the dithering feel midst change of direction you get from lesser vehicles. Point and it shoots.
Both the steel and ceramic composite brakes are confidence inspiring, delivering plenty of power and good feel. In the case of the ceramic brakes the best compliment we can think of is that they feel just like super powerful steel stoppers.
While some exotic brake set-ups are disconcertingly slow to respond from cold and offer little initial bite (the Merc McLaren SLR is shocker in this respect), the SLS's ceramic stoppers were consistent and predictable -- and never once looked like going away around Laguna's brake-battering layout. On the road the steel brakes will cope with anything you throw at them.
The long bonnet and low seating position takes some getting used to on the road, but overall sight lines are good. Over the shoulder checks when merging in traffic require a little extra care thanks to the width of the SLS's B-pillar but that's a trait with which most coupe owners learn to deal.
Nothing short of a motorcycle will give you a clear sight line through Laguna's infamous Turn Eight, The Corkscrew, however. Here even when following another SLS at less than a car length's distance, the car in front disappears as the road literally drops away. After a hard stop and squaring off the first left-hander of the corner complex, as a driver you need total confidence in the precision of the car and its levels of grip as you pitch it right and over the edge blindly. That confidence was there from lap one in the SLS -- and continued to build throughout our sessions on track.
Add to this quite forgiving responses at the limit and you have a recipe for a track day love affair. In its Sport setting the stability control system delivers some latitude to slide the car into and out of corners but not as much as say Porsche or BMW's equivalent systems. This is one area that perhaps AMG has been a little too conservative.
That the car worked well on the track wasn't entirely a surprise. Brand ambassador, GT world champ, true racing hero and AMG development driver Bernd Schneider was on hand for the Laguna launch and confirmed the standard SLS laps the Nordschleife at under 7:40 -- 15-16sec quicker than the SL65 AMG Black and better than 10sec quicker than the car the SLS effectively replaces, the Mercedes McLaren AMG SLR. And that's with two engineers onboard and a full cabin of computer data logging equipment.
At Laguna Seca it easily lapped in our hands in the low 1:40 range with Schneider's best time around 1:36. That journalists new to the track could lap within cooeee of Bernd is a testament to the competence of the SLS and its sheer pace.
On the road it was no less impressive. Though there's no mistaking the car for a soft cruiser, Mercedes has struck an excellent balance of ride and handling. The car rides hard (like all true sporties) but its response even to sharp-edged bumps and US freeways' legendary expansion joints was never harsh. It'll be interesting to see how the car copes with local conditions. We expect it to be noisy on our coarse chip roads but the ride/handling balance should translate well.
Possessed of a V8 soundtrack that should be bottled for future generations, the engine is smooth and the power delivery absolutely glitch free -- even on the preproduction cars we were driving. You could see the odd unpolished edge on some aspects of the panel fit on some of the cars used at Laguna Seca, but the powertrain calibrations were spot on.
From a slow rolling start, the SLS powers to 100mph (160km/h) in no time at all and feels like it's ready to keep charging to double that speed. Left to its own devices the gearbox shifts smartly and passing manoeuvres need just a flick of the ankle -- even in the transmission's softest mode.
On the track or in very sporty road driving the S+ mode is wonderfully predictive and pro-active, snapping downchanges under brakes of its own accord. In our initial laps at Laguna, the 'smart' transmission mode allowed us to concentrate on other aspects of the car as well as learn the track.
Though the changes themselves are lightning quick, in manual mode there's often a delay between squeezing the left-hand downchange paddle and the gearbox getting into action. AMG's engineers explained this is to protect the gearbox and that the total time (delay plus change) for the gearchange was little different than other similar systems. We don't buy this -- talking to Schneider and even powertrain boss, Dr Hart, both agree that there's still some tweaks to be done on this.
As Porsche has massaged its 911 range to span a range of buyers, so we expect AMG to tweak the SLS offer over time. The company didn't invest four years and countless Euros to develop a car that will be here today gone tomorrow.
The convertible will likely arrive in a (slightly) softer level of tune and probably get niceties like adjustable suspension in the bargain. The Black Series SLS is a beast for road and track waiting in the wings.
For now, however, the standalone SLS coupe is no less than a very polished and very serious piece of kit -- and one that is ready to serve it up to the very best supercars and coupes on sale today.
It's a fitting descendant to the sportscar that helped define the Mercedes legend.
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