Porsche marked its return to the Detroit auto show on Monday with the
unveiling of a new motorsports-inspired concept of the 918--the
company's two-seat supercar first revealed in road-going Spyder form at
last year's Geneva motor show.
Called the 918 RSR, this new advanced gasoline-electric-powered coupe
closely previews a new series-production-based race car under
development at Porsche Motorsport, which is eying a full-fledged,
factory-backed return to the famed Le Mans 24-hour race in 2012,
according to new Porsche chairman, Mathias Mueller.Â
The Le Mans link is enforced by Porsche's decision to provide its
latest concept with the number 22--the race number used by Helmut Marko
and Gijs van Lennep in their victory in the 24-hour classic in 1971 at
an average speed of 138.3 mph, for a total distance of 3,315.9 miles--a
record that stood for 39 years until Audi's victory in 2010.
In addition to pointing toward a future race car, the 918 RSR also
provides clues to the appearance of a new coupe version of the 918
which is set to be produced alongside the open-top model at Porsche's
Leipzig factory in Germany beginning in 2013.
Successor to the Carrera GT, the 918 is based around a lightweight
carbon-fiber monocoque and uses a mid-engine mechanical layout enhanced
by the addition of two electric motors mounted within the front axle
assembly.
Differing from the open-top 918 Spyder, which uses conventional
front-hinged doors, the closed-roof 918 RSR adopts gullwing-style doors
that hinge overhead.
The coupe configuration is aimed at improving overall aerodynamic
efficiency. In line with its motorsports ethos, the supercar also gains a
series of downforce-enhancing features, including small winglets up
front, vents in the front bodywork to reduce pressure within the wheel
arches at speed, a roof-mounted air duct and a large rear wing.
Powering the 918 RSR is a high-tech gasoline-electric drive system
that borrows engineering solutions from the Porsche 911 GT3 RS hybrid,
as campaigned by the German carmaker in various events during 2010,
including the famed Nürburgring 24-hour race.
Primary propulsion is provided by a mid-mounted 4.5-liter V8 gasoline
engine that kicks out 565 hp at a searing 10,300 rpm and provides drive
exclusively to the rear wheels. It is a development of the unit used by
Porsche in the earlier 918 Spyder, but with an extra 800 rpm at the top
end, it produces an added 65 hp in race trim.
The gasoline engine is supported by a pair of brushless electric
motors integrated into the front axle, where they develop a combined 204
hp and channel drive through a torque-vectoring device to the front
wheels--in the process providing the new concept
with four-wheel-drive compatibility. Altogether, the 918 RSR packs a
total of 767 hp, but only for short eight-second bursts of
electric-motor-assisted propulsion.
Departing from the earlier 918 Spyder, which uses a conventional
full-mode hybrid drive system complete with lithium-ion batteries and
plug-in charging capability, the 918 RSR relies on an advanced
kinetic-energy-recovery system (KERS) flywheel similar to that employed
on the 911 GT3 RS hybrid race car to create energy under braking and
brief periods of overrun to power the electric motors. It was developed
by engineers at the Porsche R&D center in Germany in partnership
with Williams F1 Engineering in England, which originally designed the
system for incorporation on its Formula One race car for recent FIA
regulations permitting hybrid drive. The flywheel sits in the space
usually reserved for the passenger seat and is capable of operating at
up to 36,000 rpm. The driver can call up the added 204 hp provided by
the electric motors at the press of a button.
