Detroit Debut: Mercedes-Benz Autobahn Bruiser

By Feann Torr - 11/Jan/2006

With Asian and European automakers breathing down the necks of the big American car companies, pouring more and more resources into smaller engines, hybrid and even hydrogen technology, one might come to the conclusion that even the biggest auto show in North America would be shying away from vehicles with oversized and thirsty engines.

But not just yet. Not if hard-headed companies like Mercedes-Benz have anything to say about it...

Despite the maturing of global automotive markets where many large cars - and SUVs - are falling out of favour with buyers due to high fuel costs, Mercedes-Benz is defiantly charging ahead with its flagship performance luxury model.

The Mercedes S 65 AMG is a huge vehicle in all respects. Powered by a 6.0-litre V12 engine and measuring more than 5.0 metres in length, it's the kind of vehicle that would make a Toyota Prius driver choke on his organic chai tea.

Producing a neat 570Nm of torque @ just 1000rpm, the AMG-tuned V12 engine barely needs to rev to make a decent whack, but then it picks things up just 500rpm later @ 1500rpm, when 750Nm of torque hits the crankshaft.

Everything comes together @ 2000rpm, when the force-fed 6.0-litre engine pumps out a massive 1000Nm of torque. That's right - 1000Nm. Better yet, this glut of twist is sustained on a flat torque curve until 4000rpm.

Keep up the pressure on the throttle and the hulking 5980cc engine will be pouring on the speed @ 4750rpm, when peak power of 450kW (612hp) will be antagonising the internal organs of the S 65 AMG's occupants.

Peak power is sustained until 5100rpm thanks to the smart turbo system, which consists of twin turbochargers and a single air/water intercooler that is some 70 per cent larger when compared to the superceded biturbo V12 engine. A "charge-air cooler" in Benz lingo.

The larger intercooler makes a big impact on engine output, reducing the temperature of intake air by 25% (lower air temperature = higher levels of oxygen), while the turbines and compressor wheels in both turbochargers have been upsized to cope with the increased turbo pressure of 22psi (1.5 bar). With these relatively high amounts of boost forcing more air into the cylinders of the 6.0-litre engine, it's little wonder its generates high levels of torque at such low engine speeds.

There are also other radiators scattered around the big Benz to keep its internals functioning at full boost, including an engine oil cooler behind the AMG-styled front apron, and an ancillary engine coolant radiator shoe horned in the wheel arch.

Other features new to the terrifyingly powerful 12-cylinder Benz engine include such componentry as a precision-balanced crankshaft made of super-resilient materials, the mandatory forged pistons with stronger piston pins ("made out of special material which is extremely resistant to temperature and pressure" according to Mercedes) and an internal oil-spray cooling system that consists of 12 nozzles, for individual piston attention.

As well as an electronically controlled fuel supply system, that can vary the fuel pressure instantly to match throttle input and ambient temperatures, an improved oil pump and the obligatory AMG sports exhausts system, each V12 engine is hand-built by a single AMG technician, complete with the technician's signature, which is a nice touch.

Though it's a bit of a shame such a Bahn-storming luxury sedan is limited to 250km/h (and fitted with a 360km/h speedo? That's just teasing), it's performance statistics speak for themselves. According to Mercedes-Benz the S 65 AMG can accelerate from zero to 100km/h in just 4.4 seconds, which is quick enough to give cars like the Ferrari F430 and Lambo Gallardo the willies.

And then there's the zero to 200km/h dash, which takes an incredibly quick 13.3 seconds; not bad for a vehicle that tips the scales at more than two tonnes and features a 5-speed automatic slush-box.

On top of the killer biturbo powertrain and of course all the luxury appointments one would expect of a Mercedes flagship luxury saloon, the S 65 AMG unveiled at the NAIAS also gets a chassis to keep up with the stratospheric engine performance.

Sitting on ultra-wide 19-inch alloy wheels, fitted with 255/40 ZR19 aspect ratio tyres up front and 275/40 ZR19s at the rear, the German juggernaut features an AMG sports suspension system complete with second generation Active Body Control, a system that uses hydraulic servos to adjust spring and damper settings on the go, essentially reducing body roll and pitch.

The big Merc's 5-speed transmission also features Sport, Comfort and Manual modes, each of which alters not only gear shift behaviour, but also Active Body Control settings.

Mercedes-Benz has also paid attention to the S 65 AMG's braking systems, having developed high-performance composite disc brakes measuring 390mm up front and 365mm at the rear. New twin sliding callipers (a combination of floating and fixed callipers) work in tandem with the Adaptive Brake system. In layman's terms, it means that the oversized and overweight Merc will pull up like a Suzuki Swift.

Mercedes' top shelf luxury saloon has been given the visual once-over by the AMG group, to help separate from the lesser S-Class models in the range. First and foremost, the front end benefits from a more aggressive looking and aerodynamically efficient front apron, complete with enlarged air dams to ensure the engine doesn't suffocate.

The full bodykit extends from the front apron round the sides of the car in the form of ground-hugging skirts, culminating in the deeper rear apron at the rear of the car, where the quad exhaust pipes are integrated seamlessly. The end result, together with the simple five-spoke 19-inch wheels gives the S-Class a much harder edge, while still emanating the inherent opulence of the Mercedes.

AMG has also cast its officially sanctioned tuning wand in the direction of the interior, giving the the Mercedes S 65 AMG a slightly sporty flavour. AMG logos abound, while liberal use of burr walnut trim will remind drivers that they're driving one of Germany's best. Leather upholstered ergonomic sports seats (the grain is called "Exclusive Passion" according to Mercedes) ensure comfort and lateral security, and an AMG sports steering wheel also makes the grade, featuring a sculpted rim and gearshift paddles. Lastly, AMG has included an exclusive analogue clock with its "IWC Ingenieur" (from the limited edition CLS-Class) in the centre console, just for good measure.

Mercedes did show low emissions vehicles at the 2006 Detroit Motor Show, in line with most other automakers, but still had room for its maniacally overpowered 4.4 second biturbo V12. Big engines may be on the decline as high petrol prices continue to stymie large car sales, but the boys at AMG aren't likely to down tools just yet...