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AMG's SLS Gullwing driven

2010-07-19 09:32

Lance Branquinho

In case you’re wondering, pyrotechnics detonate (shearing the door bolts) to ensure you can get out even if the SLS is upside down – not that it is going to end up in such a posture considering its harmony of dynamic talents.

Vehicle Specs
Manufacturer Mercedes-Benz
Engine 6.2l V8
Power 420kW @ 6 800r/min
Torque 650Nm @ 4 750r/min
Transmission Seven-speed DCT
Zero To Hundred 3.8 sec
Top Speed 317km/h (limited)
Fuel Tank 84l
Fuel Consumption 13.2l/100km
Weight 1 620kg
Boot Size 176l
Tyres F: 265/35 R19 R: 295/30 R20
Front Suspension Aluminium double-wishbone suspension, coil springs
Rear Suspension Aluminium double-wishbone suspension, coil springs
You have to admire Christoph Jung’s fortitude.

As SLS project team leader Jung knew he had severely tempted fate the moment those roof-hinged doors were signed off.

Simply put, Jung and his team at AMG were attempting the unthinkable – reinventing a legend, the original 300SL Gullwing.

You may think six decades of technology hence would enable AMG to effortlessly usurp the appeal of the original Gullwing with a contemporary incarnation.

Fundamentally though, nobody likes a sequel – especially if the original was something as brilliant as the 300SL.

Forget the Gullwing doors for a moment; there were many technical features distinguishing the 300SL. This was a car which, for instance, fed its in-line six cylinder engine with direct fuel-injection. Back in 1955.

You can understand how AMG’s decision to produce a modern Gullwing performance two-door would be seen as design suicide by some. It would have to be a technological tour de force to do justice to its signature vertically-opening doors.

An in-house job

There is little doubt AMG was not exactly thrilled when Mercedes-Benz optioned to engage McLaren as a technology partner for its first supercar since the original 1950s 300SL. The SLR McLaren’s Woking roots were viewed as an affront to Affalterbach’s impeccable engineering pedigree.

As the agreement between McLaren and Mercedes-Benz waned, AMG saw its opportunity.

The SLS AMG concept germinated due to two reasons.

Firstly, Mercedes required an SLR McLaren replacement to round off its performance car portfolio. The second, and perhaps more urgent reason, was AMG’s desire to prove it could design, engineer and produce a performance car – dispelling its reputation simply as a source of oversized engines and elaborate wheels for Mercedes-Benz products.

After a pretty swift 37- month development period, Affalterbach rolled out its Gullwing reincarnate to local buyers.

For the first time ever Affalterbach had not simply slotted in a 6.2l V8 engine, reduced the ride height and added some fancy wheels to an existing Mercedes-Benz platform. The SLS AMG is all of its own doing.

In terms of styling and proportions the car cues a classic front-engined, rear-wheel drive silhouette. The front third of the car’s surfacing is quite geometric, whilst the rear tapers off neatly into a concave rump section.

From the rear it looks a trifle underwhelming (with the spoiler retracted), though the surfacing is very clean. The bodies are built by Magna Steyr in Austria, then shipped to Mercedes-Benz’s Sindelfingen plant for final assembly.

Peculiarly, though perhaps not completely by surprise, the SLS AMG looks quite fetching with its doors spread. Obviously you can’t drive with them open, as the car’s ECU unit halts Gullwing-pose progress at around 50km/h…

It may not be as elegant as the original Gullwing, yet the SLS AMG is neat and purposeful in execution. If you really wish to make a statement the R125 000 Alubeam Silver paint finish is an enticing individualising option.

Remove the 300SL-inspired styling and you’ll find a car bristling with debut Mercedes-Benz technology. In a way the SLS is, on an engineering level, a truer successor to the 300SL than McLaren’s SLR was.

Technically distinguished

The SLS debuts a raft of new technologies for Mercedes-Benz’s product portfolio. Chief amongst these is the transaxle seven-speed dual-clutch transmission (designed by Getrag) and carbon-ceramic brakes at each wheel corner. Contrasting these new features is a slightly sad engineering footnote – the SLS AMG’s engine.

Rated at 420kW this is set to be the final incarnation of Affalterbach’s legendary M156  6.2l V8. In future, AMGs are to benefit from forced induction.

To ensure the SLS AMG’s swansong 6.2l V8s are the most potent ever, engine development chief Friedrich Eichler commissioned a new magnesium intake, featuring eight individual velocity stacks, fed by two electronically controlled throttle plates.

Extracting the exhaust gases are a set of headers, replacing the stock 6.2l V8 cast exhaust manifold.

The SLS AMG’s valve-gear has been reengineered too, and the Gullwing car’s 102.2mm cylinder bores are inhabited by forged (instead of die-cast) aluminium pistons.

As mentioned, the changes swell peak output by 34 units to produce 420kW at 6 800r/min, backed by 650Nm of peak rotational force. In a car weighing only 1 620kg, this equates to 0-100km/h in a scant 3.8 seconds, with top speed limited at 317km/h in the interest of tyre longevity.

Featuring double-wishbone suspension at all four wheels and keeping things as dynamically pure as possible by not employing adaptive dampers, the SLS AMG’s key design features cue a car for the purist.

Works on the road

During our evaluation drive (lapping Kyalami and a short run from the circuit to Kromdraai and back) the SLS AMG’s design virtues were tempered by reality.

Firstly, the Gullwing doors are not merely a retro styling gimmick. Requiring only 363mm of operating space they’ll open cleanly in a parking space a lot narrower than conventional swing doors. Just remember to grab the handle as you settle down into the seat – it is embarrassing to get out to regain your grip on the grab handle to ensure it closes as you sit down again…

The cabin architecture is open to a diffuse combination of trim and texture options. Of the SLS AMGs we sampled, the composite console trim and black leather was the best combination to my mind. Classic Mercedes aviation-themed air vents, a new split vertical-spoke steering wheel and redesigned instrument binnacle tally the major cabin design elements of the SLS.

Does it go though? Well, I sampled the SLS on a ride and drive from Kyalami to Kromdraai and back before lapping the circuit. Obviously Dr. Thomas Weber, AMG research and development executive, never envisioned the SLS to traverse roads of such vacillating quality as Gauteng has.

Suffice it to say, AMG’s modern-day Gullwing supercar’s wheel oscillation and rebound calibration is best suited to billiard table smooth road surfaces.

What did appeal on the public road ride and drive was the DCT transmission’s smoothness and the big-block acoustic signature of the 6.2l V8  - especially on overrun. Perhaps one good consequence of the ill-fated Daimler-Chrysler marriage was German exposure to HEMI V8s, because the SLS AMG’s engine is simply the loudest, most sinister V8 soundtrack available in a car with catalytic converters. It sounds like popcorn being made in a nuclear reactor.

The only major debit found during the road drive was an ergonomic one - the cruise control stalk being inadvertently activated when downshifting via the column mounted paddle shift. Surely a car as dynamically focused as the SLS AMG is enhanced by the exclusion of cruise control in principle?

And on the track

Returning to Kyalami for a few laps of the undulating Highveld circuit quickly exposed the SLS AMG’s talents. Chiefly, it does three things remarkably well.

Firstly, it makes an unholy noise.

Secondly, it builds road- and crankspeed with alarming urgency. Between the engine and road speed dials there is a seven-bar LED display acting as a shift guide of sorts.

The first four bars are white, the fifth one yellow and last two red. If you don’t shift by the time the yellow illuminates you’re stuck on the limiter.

For something of such voluminous capacity, the SLS AMG’s 6.2l V8 converts combustion to piston-speed with competition engine urgency.

Thirdly, it is very well balanced. The rigid aluminium spaceframe chassis, set damping and steering rack location (ahead of the front wheels’ centre point) ensure the SLS AMG turns-in dutifully, even if you are slightly optimistic with your entry speed. Down Kyalami’s mineshaft into the bowl – for instance – it handled the sudden change of axle load and direction with aplomb.

To illustrate just how well balanced the SLS is, Mercedes-Benz’s product specialist Graeme Ingram took me into a pit garage housing all the tyres they intended using for the media event. On closer inspection the worn-in tyres all had symmetrical abrasion patterns across the width of their tread, instead of the asymmetrical left or right bias usually found when road cars are pounded around a demanding circuit.

It is hardly cheap at R2.5 million, yet the SLS AMG feels genuinely special. The local models are better equipped than some other markets too. South African customers get dual-zone climate control, parktronic, COMMAND navigation, reversing camera, integrated media interface and neat car cover as standard.

Carbon-ceramic brakes are R140 000 and the laboriously adjustable AMG bucket seats (requiring complete unbolting to go up or down) are R17 500.

Can you really put a price on the joy (and sound?) of owning the last naturally-aspirated AMG V8 supercar? Thought so. 


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