McLaren MP4-12C revealed

Chassis, suspension

The MP4-12C’s chassis is special, even among carbonfibre tubs. Unlike others, which consist of several major carbon components bonded together, the 12C’s ‘Monocell’ chassis is a hollow one-piece affair built using a new process that has taken five years to develop.

McLaren believes the Monocell process could revolutionise car design by finding its way into more mainstream cars. A 12C chassis can now be built in just four hours at less than a tenth of the cost of the McLaren F1’s chassis in 1993. It weighs a mere 80kg, yet it provides most of the car’s class-beating rigidity and does a myriad of jobs, including providing direct mounts for the steering and front suspension.

The 12C tub bolts directly to an engine/suspension cradle made of aluminium extrusions and there are crushable alloy structures at either end, beneath the SMC body panels.

Why no carbonfibre panels? Carbon would be costly and deliver no extra function; better to spend the money on fruitful refinements in other areas.

The 12C has electro-hydraulic rack and pinion steering and double wishbone/coil spring suspension at both ends. There’s the usual suite of electronic aids, including ABS, ESP, ASC traction control, electronic brake distribution and hill hold.

To that, McLaren adds something it pioneered in its F1 cars: brake steer, which applies the inside rear brake as the car corners, to aid turning.

The new McLaren also has a unique rear deck-mounted airbrake, in effect an electrically operated spoiler that can deploy much faster than usual (aided by clever use of aerodynamic forces) to improve stability under braking and increase retardation.

However, the big suspension story is the 12C’s pioneering use of electronic interconnection of all four adjustable dampers. This has allowed the engineers to ditch conventional mechanical anti-roll bars and create what they call “a unique relationship between ride and handling”.

When the car’s various wheel and motion sensors detect cornering, they increase cross-car damper rates to keep it nearly flat. But when it is travelling in a straight line they adopt more supple rates to provide something close to an executive saloon’s ride quality.

There are three different suspension modes (normal, sport, high performance) that adjust throttle curve, steering effort, ESP settings and ride parameters according to driver preference.

Powertrain

McLaren won’t say much about the MP4-12C’s engine, but the few details it is providing carry quite a punch.

It’s a British-built 90-degree V8 of 3.8 litres, rigid and compact in design, with double variable valve timing, and is force fed by twin turbochargers. This is no AMG cast-off, insists McLaren, but a compact design whose flat-plane crank and dry sump allow it to be mounted low down in the car.

Power is a class-beating 600bhp and the rev limit is 8500rpm, yet the motor also produces around 440lb ft of torque – and around 80 per cent of it is available below 2000rpm.

The gearbox is a seven-speed Graziano twin-clutch, twin-paddle affair, and there will be no classic stick-shift version. For one thing, McLaren is convinced the DSG is better; for another, providing a third pedal in its footwell would crowd its allotted shoe space. There’s enough room for drivers of all statures, engineers say.

McLaren calls the seven-speeder its SSG (for Seamless Shift Gearbox) and provides a variety of shift modes: normal and sport, plus a launch control, a winter mode and an ‘automatic’. The gearchange paddle pivots on the steering wheel boss like a racing car, so that as you pull one paddle, the other moves out.

There’s a ‘first pressure’ setting that McLaren calls Pre-Cog, which prepares the gearbox for an imminent change by showing which way it will go.

Interior

The cabin feels snug, a little like a tailored suit, but McLaren’s designers have tried hard to keep things simple and conservative.

Still, there is a surprising amount of space for small objects (there’s a big tray behind the seats and a Volvo-like space behind the centre console).

Surprisingly for a car whose creators talk a lot about racing connections, there are no wheel-mounted switches – they’re all grouped on stalks, or logically on the centre console – and the instrument pod consists of a solitary round tacho dial with a digital readout for speed and wings on either side that provide lesser information.