The Porsche 918 Spyder is on the road. Driving trials of the super sports car of the future have progressed with completion of the prototypes.Porsche says the 918 Spyder will go into production at the end of September 2013, as planned, and the first customers will get their cars before the end of that year.Wolfgang Hatz, a member of the executive board for research and development at Porsche AG, said: "With the 918 Spyder we are redefining driving fun, efficiency and performance."4.6-LITRE V8The prototypes, their camouflage harking back to the historic Porsche 917 race cars, signal the final touches to the 918 Spyder. The focus, Porsche says, is on the integration of the sophisticated individual drive components.The combination of a 4.6-litre V8 petrol engine and two independent electric motors (one on the front axle, the other in the drive line and driving the rear wheels) is said to pose completely new demands on the development of the operating strategies.Hatz explained: "They are, therefore, a critical component in this vehicle into which we have put all of our expertise and capacity for innovation." Porsche 918 Spyder hybrid image gallery.These operating strategies and the development of the software to go with them are, Porsche says, one of the automaker's "core competencies". It adds: "The two disciplines have a major influence on the extremely high level of driving enjoyment offered by the 918 Spyder and deliver a unique combination of minimal fuel consumption and maximum performance."The initial results of the driving trials are in line with the high expectations placed on the 918 Spyder."The 918 Spyder has been designed as a plug-in hybrid whose high-performance combustion engine and cutting-edge electric motors combine for extraordinary performance: the dynamics of a racing machine boasting 575kW but with fuel consumption in the region of three litres/100km."MONOCOQUE SHELLThe car has a complete carbon-fibre reinforced plastic (CFRP) monocoque shell with fully adaptive aerodynamics, adaptive rear-axle steering and an upward-venting exhaust.Porsche says the 918 Spyder is just a glimpse of what 'Porsche Intelligent Performance' may be capable of in future.Porsche 918 Spyder provisional specificationsBody: Two-seater Spyder; carbon-fibre reinforced plastics (CFRP) monocoque interlocked with CFRP unit carrier; two-piece Targa roof; fixed roll-over protection system.Drivetrain: Parallel full hybrid; 4.6-litre V8 mid-engine with dry sump lubrication; hybrid module with electric motor and decoupler; electric motor with decoupler and gear unit on front axle; electrical system recuperation; four cooling circuits for motors, transmission and battery; thermal management.Engine power: More than 425kW.Electric drive: 90kW (hybrid module on rear axle); 80kW (electric motor on front axle), 575kW combined.Suspension: Double-wishbone front axle; optional electro-pneumatic lift system on front axle; electro-mechanical power steering; multi-link rear axle with adaptive electro-mechanical system for individual rear wheel steering.Brakes: High-performance hybrid brake system with adaptive recuperation; ceramic brake discs (PCCB).Energy supply: Lithium-ion battery with 6.8kWh capacity, 202kW maximum power and mains-compatible plug-in charger.Performance: Top speed more than 325km/h.Purely electric: More than 150km/h.Acceleration: 0-100km/h less than three seconds.Fuel consumption (NEDC): 3 litres/100km.CO2 emissions: Total about 70g/km.Range: Purely electric: More than 25km.