Porsche : Porsche Carrera GT
Production-Based Sports Car Concept with Thoroughbred Racing Technology
For the first time since 1993, when the forerunner to the Porsche Boxster was presented in Detroit, Dr. Ing. h.c.F. Porsche AG is once again unveiling a production-based sports car concept at an international motor show. The top-performance Carrera GT sports car making its debut at the Paris Motor Show is entering new dimensions, reaching beyond even the most extreme limits of modern sports car technology.
As with the Boxster, only a small step remains to series production of this supreme sports car of the highest conceivable calibre. Indeed, the concept car might become reality as early as in 2003, naturally in an exclusive series of very special models for very special purchasers.
In its design and construction, this concept roadster is based on pure racing technology of the highest standard: This applies to the chassis, the suspension and the brakes, as well as the new V10 normal-aspiration power unit and the six-speed manual gearbox complete with a thoroughbred motor racing clutch. As in motorsport, the drivetrain and suspension form one unit with the spring struts of the rear axle pivoting on the gearbox. Displacing 5.5 litres and developing maximum output of 410 kW (558 bhp), the engine guarantees supreme performance and a top speed of over 330 km/h. Acceleration from 0-100 km/h comes in less than four seconds.
The design of this uncompromising super-sports car is Porsche all the way. The objective was to express the supreme thrill of a Porsche racing car in a new blend of emotional and functional design. While prototypes designed and built for racing alone rarely resemble their series production counterparts, creating a genuine Porsche identity was one of the basic demands made of the designers in this project.
Given this philosophy, the front view of the car is dominated by that typical Porsche "face" with its arrow-like front lid. Emulating the looks of the legendary 718 RS Spyder back in the '60s, the oval main headlights extending back in an angle towards the middle of the car each come with two large round reflectors. Even at very first sight they will remind you in their design and clarity of the precision of a sophisticated, top-quality camera lens – and light technology of the very best comes within these headlight units featuring bi-xenon gas discharge lights, currently the only system in the world able to generate both the low beam and the high beam in one. Three delicate neon tubes serve as direction indicators, neon light technology also being used at the rear, for the side indicators, and on the brake lights positioned higher up than usual. The lower front section is made up primarily of a very dynamically designed air intake scoop feeding cooling air both to the radiator and the front brakes. And again reflecting the special look of racing cars in former times, the additional headlights positioned relatively close together are also to be found here.
Mighty air outlets in front of the doors discharging the air drawn in for the radiator and front brake cooling, and more air intake scoops of at least the same size behind the doors, characterise the styling of the Porsche Carrera GT from the side. The shoulder line extends smoothly and dynamically from front to rear, stretched out over the front and rear wheels and ultimately merging into the side sections of the retractable rear wing. All the proportions of the car from the side, with the cockpit clearly oriented towards the front, and the long distance between the door and the rear axle, accentuate the sporting mid-engined concept. Both to provide a clear view of the engine and for thermal reasons, the power domes stretching from the rollbars to the rear are made of perforated light alloy.
Smooth and stable even at very high speeds
The clearly designed rear end with LED lights and two oval tailpipes reveals a design concept focusing in particular on driving dynamics and aerodynamic qualities. The upper part of the rear end is clearly defined by the wing integrated harmoniously into the overall design of the car, doing its job incon-spicuously but effectively whenever extending out from a speed of 120 km/h and generating enormous downforce at top speed.
The front wheels are pressed down at speed by the same kind of force, the radiator extending upwards at a specific angle and special air guidance ducts in the front section creating a powerful flow of air to force down the front wheels safely on to the road. Yet another, highly effective design element generating additional downforce is integrated beneath the car, where Porsche's aerodynamicists have created a fully covered, smooth underfloor together with a rear-end diffuser to provide an additional suction effect. While, as is well known to the connoisseur of aero-dynamics, design features of this kind always increase the drag coefficient, supreme stability at high speeds has clear priority in this case over a seemingly sensational drag coefficient of relatively little significance in practice.
Porsche's commitment to supreme driving dynamics and driving safety is expressed from the start by the basic concept of this new sports car design closely resembling production standards: Measuring 4.56 metres in length, 1.92 metres in width, 1.19 metres in height, and with a wheelbase of 2.70 metres, the Carrera GT has an extremely low centre of gravity. In conjunction with the fuel tank providing more than 90 litres or approxi-mately 20 Imp gals capacity in its carefully protected position behind the passenger cell, and as a result of the mid-engine concept, this concentrates the weight of the car near its central point, ensuring a consistent axle load distribution as an essential prerequisite for supreme performance and driving characteristics on the road. The use of carbon-fibre as the basic material for the body combines optimum body stiffness and superior body safety with very low vehicle weight of approxi-mately 1250 kg.
Racing technology at its best for the engine and transmission
Not least, this ultra-low weight of the Carrera GT is attributable to the new, extra-light V10 normal-aspiration power unit displacing 5.5 litres. Maximum output is 410 kW or 558 bhp, maximum torque more than 600 Newton metres or 442 lb-ft, with the engine speed range extending to well over 8000 rpm. Four valves per cylinder and intake ducts designed for optimum flow conditions ensure a perfect charge of fuel and air to all cylinders. These engine data and performance figures are incidentally still provisional and may become even more impressive should the Porsche Carrera GT enter series production.
The engine itself is made exclusively of light alloys, most of which are highly stable and naturally temperature-resistant. This applies both to the crankcase and to the cylinder heads, with a special light alloy absolutely immune to even the highest temperatures. To keep the engine as short and compact as possible, in turn, the designers have done without the usual integrated cylinder liners, the cylinders instead featuring a low-friction Nikasil layer (ie, a mixture of nickel and silicon) on the surface, a structure also helping to make the crankcase much stronger and more stable. Yet a further advantage is offered by the enhanced cooling, the cylinders being surrounded directly by the coolant to provide an even better heat transfer from the pistons to the coolant under all conditions and at all speeds.
The pistons are connected to the crankshaft by titanium conrods combining supreme stability with low weight and thus ensuring outstanding smoothness and endurance at engine speeds in excess of 8000 rpm. A racing clutch and a compact, manual six-speed gearbox then serve to provide an optimum flow of drive power to the wheels. This drivetrain and, in particular, the small diameter of the clutch plates, allow the crankshaft to be fitted at an extremely low point further lowering the car's centre of gravity. This low construction is then further enhanced by the absence of a conventional oil sump beneath the crankcase, oil being supplied by dry sump lubrication with a separate oil tank integrated in the transmission housing. A further advantage of this system carried over from motorsport is the optimum supply of oil to the engine even under extreme lateral acceleration for a long period.
The transmission housing also provides the pivot points for the rear double-wishbone axle, with individual adjustment of the wheel springs and anti-roll bars, like on the front double-wishbone axle with its integrated spring/damper units. The spring/damping units on the rear axle are actuated by pivot levers and pushrods (spring struts fastened to the transmission), allowing a very aerodynamic configuration of the engine and transmission unit.
Supreme brake power built in from the start
The front wheels measure 265/30 R 19, the rear wheels 335/30 R 20. This difference in size on the super-light forged magnesium rims helps to improve the car's superior handling to an even higher level, a further advantage of 19- and 20-inch wheels being the option to use brake discs significantly increased in diameter. Accordingly, the brake discs on this sports car concept measure an enormous 380 millimetres or 14.96" in diameter, 50 millimetres or 1.97" more than the very large brake discs already featured on the 911 Turbo.
It almost goes without saying that Porsche uses ceramic, and not grey-cast-iron, brake discs to slow down a car of this calibre. Indeed, Porsche is the first car maker in the world to develop composite ceramic brake discs with an involute cooling duct for efficiently cooling the brakes inside. Proudly bearing the name Porsche Ceramic Composite Brake (PCCB), this new brake system sets an entirely new standard in terms of brake response, fading stability, weight and service life. Like metal brake discs, the ceramic composite brake discs are cross-drilled and inner-vented, but weigh more than 50 per cent less. In combination with the all-new brake lining, the ceramic discs immediately build up an extremely high, consistent frictional coefficient during application of the brakes. Abrasion of the discs and linings themselves is reduced to an absolute minimum, making the Porsche Ceramic Composite Brake a genuine lifetime component also thanks to the avoidance of any corrosion. And in conjunction with the first-ever 8-piston brake callipers featured at the front and four-piston brake callipers at the rear, stopping power ranks high up in the domain of genuine racing cars.
Exemplary safety standard
The bodyshell itself is based on a carbon-fibre structure, carbon-fibre being the only material able to combine supreme performance and driving dynamics with minimum weight and maximum stability. Steel structure elements are used in order to ensure optimum crash behaviour, allowing maximum plastic energy absorption in conjunction with optimum safety design and a consistent standard of excellence throughout production. The tank itself is kept safely out of harm's way right behind the passenger cell, also ensuring an optimum axle load distribution regardless of whether it is full or empty.
In the interest of enhanced passive safety – particularly in an open car – the interior features a spaceframe made of high-strength aluminium profiles efficiently conveying longitudinal forces in a head-on collision to the rear also through the doors. Forces encountered above all in a side-on collision, in turn, are conveyed to the body structure by transverse bars in the area of the instrument panel and the rear bulkhead. This innovative concept serves to create a highly effective safety "cage" of minimum weight, simply by avoiding any diversion of force lines.
Driver and passenger airbags, as well as the POSIP (Porsche Side Impact Protection) side airbag system developed especially for open cars, round off this safety concept. Offering a volume of 30 litres, the POSIP airbags are particularly large, protecting the occupant in a side-on collision not only on chest and hip level, but particularly around his head.
Leather and aluminium – nothing else
Two materials in particular dominate the interior of the car: aluminium and leather. Aluminium has been given preference above all round the instrument panel, where it is used as a structural element creating a particular look and emanating very special flair. The centre console rising up to the cockpit is also finished in aluminium, creating an exceptional design feature with the gearshift lever at the upper end complete with its aluminium gearshift lever knob finished partly in leather and resting at exactly the same height as the steering wheel. A positive spin-off effect of this feature is the further enhancement of the car's flexural stiffness. The control units for the audio system and air conditioning are integrated on the centre console just beneath the gearshift lever, within easy and convenient reach, without requiring the driver or passenger to move their hands any particular distance.
The all-new seats are finished in brown leather combined with black Nubuk suede. Since electric motors for adjusting the seats would not be appropriate in a thoroughbred sports car of this calibre, where every gram counts, Porsche's engineers and designers have opted for a very straightforward but nevertheless elegant concept most appropriate for an outstanding sports car of this calibre: All you do is pull a light aluminium handle at the front centre of the seat in order to adjust its fore-and-aft position. Optimum body support for longitudinal and lateral forces, in turn, is ensured by a very sophisticed and elaborate concept, new knee and leg supports enabling the driver and passenger to remain firmly in the right position according to their individual requirements. Then, to access and leave the car with ease, these knee and leg supports conveniently fold away to the side. The side supports on the seats, finally, can also be adjusted for width in order to fit the driver's and passenger's body perfectly.
Again reflecting the highest standard in motorsport, the steering wheel rim is finished in high-quality suede offering an optimum grip. Another contrasting point on the steering wheel is the Y-shaped aluminium frame comprising the airbag module at the bottom and once again taking up the force-feed bars in the door frame.
The instruments feature the most advanced display technology with a TFT colour screen, the display philosophy as such following the special standards required in motor racing. The emphasis, therefore, is placed on racing-oriented display functions such as the rev counter, water temperature, oil pressure and route information even presenting your lap time on a specific track or circuit. To meet the requirements of road traffic in the same way, the instrument cluster also comprises functions such as a road speed indicator as well as various telltales. A second display level the driver may activate whenever required offers a wide range of information for everyday motoring, the on-board computer providing display functions, inter alia, such as your trip mileage, the range still remaining on the fuel in the tank, the outside temperature, time of day, and the frequency tuned in on the radio. And on special request it can also present the air conditioning data currently set.
A fundamental display function essential on every Porsche clearly remains active on both levels of the display unit: the engine speed shown by a classic instrument dial. And it almost goes without saying that Porsche's designers have given particular signifi-cance to another traditional detail: the ignition key inserted into the lock on the left side of the steering wheel.