With the 918 Spyder undergoing the final stages of development, Porsche is keeping us updated with a new photo gallery and some interesting new technical details about its upcoming flagship "hypercar".
Porsche says the 918 Spyder benefits from the development of race cars for the 24 hours race in Le Mans in 2014. The rolling chassis is the core of the 918 Spyder and can be driven even without a body on top of it – a tradition inherited from Porsche racecars.
As we already know, the all-wheel drive concept of the 918 combines a gasoline engine with an electric motor on the rear axle and a second electric motor on the front axle. The powertrain is based on knowledge gained by Porsche during races with the 911 GT3 R Hybrid.
Porsche states that the individually controllable front drive allows for high and safe cornering speeds, while the advanced “boost” strategy lets the full power of the car to be tapped into by simply fully pressing the accelerator. The current lap time for the North Loop of the Nurburgring is 7:14 minutes, a time set in September 2012, more than a year before the start of production. With the prototype being already 20 seconds quicker than the Carrera GT, the final production model is expected to lap the Nordschleife even faster.
With a combined output of over 880 PS (868 hp), the 918 Spyder averages 3 liters/100 km (78.4 mpg) – keep in mind, that's with the use of the electric motor. It has an unladen weight of approximately 1,640 kg (3,615 lbs) when fitted with the optional “Weissach” package. This is possible thanks to the use of lightweight materials such as CFRP (carbon fiber reinforced polymer). Also, drivetrain components weighing over 50 kg (110 lbs) are located as low and as centrally as possible within the vehicle.
Weight distribution is slightly rear end biased, with 57 percent on the rear axle and 43 percent on the front axle. The center of gravity is extremely low, at approximately the height of the wheel hubs.
The 918 Spyder has a multi-link chassis complemented by additional systems such as the PASM adaptive shock-absorber system and rear-axle steering. At low speeds, the system steers the rear wheels in a direction opposite to that of the front wheels, helping cornering and reducing the turning circle. At higher speeds, the system steers the rear wheels in the same direction as the front wheels, improving the stability of the rear end when changing lanes quickly and, consequently, handling.
Handling is also improved with the help of the Porsche Active Aerodynamic system that operates in three modes, from optimal efficiency to maximum downforce.
To operate the three power units, there are five modes that can be activated from the steering wheel. The “E-Power” mode is the default operating mode providing a range of over 30 km (18.6 miles) on purely electric power. Even in battery mode alone, 0-100 km/h (62mph) is covered in under 7 seconds and top speed is 150 km/h (93.2 mph). When the battery level drops, the system automatically switches to hybrid mode.
In “Hybrid” mode, the electric motors and combustion engine work alternately with a focus on maximum efficiency and minimum fuel consumption. In “Sport Hybrid” mode, the combustion engine operates continuously and provides the main propulsive force. It is also aided by the electric motors in the form of electric boosting.
There’s also a “Race Hybrid” mode used for maximum performance and a very sporty driving style. The emphasis is put on the combustion engine, with support from electric motors in the form of boosting. The 7-speed PDK transmission helps with a set up for sportier driving. Drivers can also use the “Hot Lap” button that releases the final reserves of the 918 Spyder. Similar to a qualification mode, it utilizes all of the available energy in the battery.
Derived from the unit in the RS Spyder racecar, the naturally aspirated 4.6-liter V8 engine develops 608 PS (600 hp) and revs up to 9,150 rpm. It has a power output per liter of approximately 132 hp/l, more than any Porsche naturally aspirated engine and 18 hp/l more than the Carrera GT’s engine.
The hybrid module includes an electric motor developing 115 kW (155 hp) and a decoupler that serves as the connection with the combustion engine. The parallel hybrid configuration allows the rear axle to be powered by either the combustion engine or electric motor or via both drives jointly. Both the combustion engine and the motor are placed in front of the rear axle and don’t have any direct mechanical connection to the front axle.
The front axle is powered by another independent electric motor developing 95 kW (127 hp), with energy coming from a 7 kWh liquid cooled lithium-ion battery. The battery can be recharged in four hours using the supplied Porsche Universal Charger (AC) or in 25 minutes using the optional Porsche Speed Charging Station (DC).
While some may consider a bit strange to offer an optional package on an $845,000 car, Porschedoesn’t and it provides the Weissach package that brings special colors and designs based on legendary Porsche race cars. The roof, rear wings, rear-view mirrors and frames of the windscreen are made of visible carbon, while parts of the interior are upholstered with Alcantara instead of leather, and visible carbon replaces much of the aluminium. Weissach models are also about 35 kg (77 lbs) lighter.
By Dan Mihalascu
Technical Specifications – Porsche 918 SpyderBody: Two-seat Spyder; carbon fiber reinforced plastics (CFRP) monocoque interlocked with CFRP unit carrier; two-piece Targa roof; fixed roll-over protection system.
Drivetrain: Parallel full hybrid; 4.6-liter V8 mid-engine with dry-sump lubrication; hybrid module with electric motor and decoupler; electric motor with decoupler and gear unit on front axle; auto start/stop function; electrical system recuperation; four cooling circuits for motors, transmission and battery; thermal management.
Engine power: 608 hp at 8,600/min (V8 engine)
154 hp (hybrid module on rear axle)
127 hp (electric motor on front axle)
887 hp (combined)
Max. torque: 390 lb.-ft. at 6,600/min (V8 engine)
940 lb.-ft. (equivalent torque calculated on the crankshaft, complete system in 7th gear)
787 lb.-ft. (complete system, 3rd gear)
> 590 lb.-ft. (800/min – 5,000/min)
Maximum Revs: 9,150 rpm
Power output per l: 133 hp/l (V8 engine)
Power transmission: Combustion engine with hybrid module and transmission bolted together to form a single drive unit; seven-speed Doppelkupplungsgetriebe (PDK); rear-wheel drive; front electric motor with gearbox for driving the front wheels (decoupled from 146 mph); five pre-selectable operating modes for optimum coordination of all drive units.
Gear ratios PDK
1st gear 3.91
2nd gear 2.29
3rd gear 1.58
4th gear 1.19
5th gear 0.97
6th gear 0.83
7th gear 0.67
R gear 3.55
Final drive ratio 3.09
Clutch diameter 8.7 in. / 6.5 in.
Chassis and Suspension: Double-wishbone front axle; optional electro-pneumatic lift system on front axle; electro-mechanical power steering; multilink rear axle with adaptive electro-mechanical system for individual rear wheel steering; electronically controlled twin-tube gas-pressure dampers in the front and rear with Porsche Active Suspension Management (PASM).
Brake system: High-performance hybrid brake system with adaptive recuperation; internally ventilated and perforated front ceramic brake discs (PCCB), 16 in. in diameter and 1.4 in. thick; rear discs 15.4 in diameter and 1.3 in. thick.
Wheels and tires: 918 Spyder wheels
(Weissach package: 918 Spyder magnesium wheels)
front 9.5 J x 20 with 265/35 ZR 20
rear 12.5 J x 21 with 325/30 ZR 21
Weights: Curb weight 3,715 lbs.
3,616 lbs. (Weissach package)
Dimensions: Length 182.8 in.
Width 76.4 in.
Height 45.9 in.
Wheelbase 107.5 in.
Track width front 65.5 in.
rear 63.5 in.
Luggage compartment capacity, VDA ~ 110 l
Fuel tank capacity 18.5 gal
Energy supply: Lithium-ion battery with 6.8 kWh capacity (BOL nominal), 220 kW maximum power and mains-compatible plug-in charger.
Performance: Top speed > 211 mph
purely electric 93 mph
Acceleration:
0-62 mph 2.8 s
0-60 mph less than 2.8 s
0-62 mph (in electric mode) 7.0 s
0-124 mph (0-200 km/h) 7.9 s
0-186 mph (0-300 km/h) 23.0 s
Range: Purely electric approx. 18 mi.
Warranty: Vehicle (Battery) 4 years (7 years)
Charging times:
AC charging on a household socket (110 V, 10 A): less than 7 hours
AC charging on an industrial socket (240 V, 30 A): less than 2 hours
DC charging on an industrial socket (400 V, 32 A): less than 0.5 hours.
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