(continued from above)
Hybrid Drive Brings Advantages in Terms of Driving Dynamics
A key message of the 918 Spyder is that the hybrid drive from Porsche is a plus
for no-compromise driving dynamics. Drivers can experience this thanks to the
unique all-wheel drive concept with a combination of combustion engine and
electric motor on the rear axle and the second electric motor on the front axle.
It is based on knowledge gained by Porsche during motor races with the
successful 911 GT3 R Hybrid. Due to the additional, individually controllable
front drive, new driving strategies for extremely high, safe cornering speeds
can be implemented, especially for bends. Furthermore, the advanced "boost"
strategy manages the energy of the electric drive so intelligently that, for
every sprint with maximum acceleration, the full power of the 918 Spyder can be
tapped into by simply pressing the accelerator down fully. In short, the 918
Spyder allows even drivers without motorsport training to experience the
potential of advanced longitudinal and transverse dynamics.
Chassis with Race Car Genes and Rear-Axle Steering
The multi-link chassis of the Porsche 918 Spyder is inspired by motorsport
design, complemented by additional systems such as the PASM adaptive
shock-absorber system and rear-axle steering. Basically, this incorporates an
electro-mechanical adjustment system at each rear wheel. The adjustment is
speed-sensitive and executes steering angles of up to three degrees in each
direction. The rear axle can therefore be steered in the same direction as the
front wheels or in opposition to them. At low speeds, the system steers the rear
wheels in a direction opposite to that of the front wheels. This makes cornering
even more direct, faster and more precise, and it reduces the turning circle. At
higher speeds, the system steers the rear wheels in the same direction as the
front wheels. This significantly improves the stability of the rear end when
changing lanes quickly. The result is very secure and stable handling.
Porsche Active Aerodynamic (PAA) for Different Driving Modes
Porsche Active Aerodynamic (PAA), a system of adjustable aerodynamic elements,
ensures unique and variable aerodynamics; its layout is automatically varied
over three modes ranging from optimal efficiency to maximum downforce and is
tuned to the operating modes of the hybrid drive system. In "Race" mode, the
retractable rear wing is set to a steep angle to generate high downforce at the
rear axle. The spoiler positioned between the two wing supports near the
trailing edge of the airflow also extends. In addition, two adjustable air flaps
are opened in the underfloor in front of the front axle, and they direct a
portion of the air into the diffuser channels of the underbody structure. This
also produces a "ground effect" at the front axle.
Main Propulsion: The Race Car's Eight Cylinder Engine
The main source of propulsion is the 4.6-liter, eight cylinder engine that
produces 608 hp of power. The engine is derived directly from the power unit of
the successful RS Spyder, which explains why it can deliver engine speeds of up
to 9,150 rpm. Like the race engine of the RS Spyder, the 918 Spyder power unit
features dry-sump lubrication with a separate oil tank and oil extraction. To
save weight, components such as the oil tank, the air filter box integrated into
the subframe and the air induction are made of carbon fiber reinforced polymer.
Further extensive lightweight design measures have resulted in such features as
titanium connecting rods, thin-wall, low-pressure casting on the crank case and
the cylinder heads, a high-strength, lightweight steel crankshaft with 180
degrees crankpin offset and the extremely thin-walled alloy steel/nickel exhaust
system. Striking features of the V8 are that it no longer supports any auxiliary
systems, there are no external belt drives and the engine is therefore
particularly compact. Weight and performance optimizations achieve a power
output per liter of approx. 133 hp/l - the highest power output per liter of a
Porsche naturally aspirated engine - which is significantly higher than that of
the Carrera GT (106 hp/l) and outstanding for a naturally aspirated engine.
Porsche 918 Spyder: Review (2/2)