Chevrolet today unveiled the
Corvette C7.R race car, which was
co-developed with the all-new 2015
Corvette Z06. They represent the
closest link in modern times between
Corvettes built for racing and the
road, sharing unprecedented levels
of engineering and components
including chassis architecture,
engine technologies and aerodynamic
strategies.
“When it comes to
endurance racing, Corvette has been
the benchmark of success for nearly
15 years,” said Jim Campbell, U.S.
vice president, Performance Vehicles
and Motorsports. “A great deal of
the team’s success can be attributed
to the symbiotic relationship
between Corvette Racing and the
production vehicles. The 2015
Corvette Z06 and new C7.R will be
more competitive on the street and
track due to successful design of
the Corvette Stingray – which itself
is heavily based on the C6.R race
car.”
Corvette Racing will field two
C7.R race cars in 2014, starting
later this month at the 52nd Rolex
24 At Daytona on Jan. 25-26. The
race kicks off the TUDOR United
SportsCar Championship – a new
series debuting this year after the
merger of the American Le Mans
Series and GRAND-AM Rolex Sports Car
Series. The C7.R will compete in the
GT Le Mans class in 11 races around
North America.
The team is also is expected to
compete in June at the 24 Hours of
Le Mans – a race Chevrolet and
Corvette Racing have won seven times
– in the GTE Pro class.
Since the team’s competitive
debut in 1999 with the Corvette
C5-R, Corvette Racing has earned
unmatched success. The C5-R and C6.R
led Chevrolet to 90 victories around
the world and 10 manufacturer
championships in the American Le
Mans Series. In 2013, Corvette
Racing won five races and swept the
manufacturer, team and driver
championships in the GT class for a
second consecutive season.
A key part of the team’s success
is the technology transfer between
Corvette production cars and race
cars.
“Corvette Racing sets the gold
standard for technology transfer
between the track and street,” said
Tadge Juechter, Corvette chief
engineer. “We are continually taking
what we learn in competition, and
applying it to improve production
Corvettes – which then make better
race cars. As a result, the new
Corvette Z06 is the most
track-capable production Corvette
ever while the new C7.R is poised to
be even more competitive on the race
circuit.”
Many of the architectural and
aerodynamic features of the C7.R are
based on equivalent components and
technologies from the 2015 Corvette
Z06, including:
New, aluminum frame
As before, the race car and the Z06
will share the same,
production-based aluminum frame.
However, for the first time, the
frames for the race car and
production Z06 will be built
in-house at the Corvette’s Bowling
Green, Ky., assembly plant.
By leveraging advanced
manufacturing materials – such as
laser welding, Flowdrill-machined
fasteners and a GM-patented aluminum
spot-welding process – the
production structure is
significantly stronger than its
predecessor. For Corvette Racing,
this equates to a race chassis for
the C7.R that is 40 percent stronger
than the outgoing C6.R.
“In the first lap in the C7.R,
the drivers felt the increase in
chassis stiffness,” said Mark Kent,
director of Racing for Chevrolet.
“The drivers instantly noticed that
the C7.R handling was better over
changing surface features and rough
track segments. This is important as
our drivers don’t always stay on the
smooth pavement, and are constantly
driving over curbing at corner
apexes.”
Direct-injected engine
The addition of direct fuel
injection to the Corvette Z06 will
enable the technology to return to a
Corvette race car for the first time
since the end of the GT1 era in
2009. It promises greater
efficiency, which can make a
significant difference in
long-distance endurance racing such
as Daytona and Le Mans through fewer
time-consuming pit stops.
“Direct injection offers two
advantages for the race team,” said
Kent. “First, it offers drivers more
precise throttle control, so that
even the smallest changes in the
driver’s throttle position delivers
a proportional response from the
engine. Second, direct injection
typically improves fuel economy
about 3 percent. That could be
enough to bypass one fuel stop
during a 24-hour race. Given that
races are often won and lost in the
pits, a 3 percent gain in fuel
economy could translate to a
significant advantage in track
position.”
Aerodynamics
The aerodynamic strategies of the
Corvette Stingray came directly from
the Corvette C6.R – including the
forward-tilted radiator, functional
hood and front-quarter panel vents,
and rear transmission and
differential cooling intakes.
The Z06 and C7.R take that
aerodynamic foundation to the next
level, sharing aggressive strategies
for increased cooling and
aerodynamic downforce, including
similar front splitters, rocker
panels, and front- and rear-brake
cooling ducts.
“We worked concurrently with the
race team developing the aerodynamic
packages for the Z06 and the C7.R,”
said Juechter. “We even used the
same modeling software to test both
cars, enabling us to share data and
wind-tunnel test results. As a
result, the aerodynamics of the
production Z06 produce the most
downforce of any production car GM
has ever tested, and we are closing
in on the aero performance of a
dedicated race car.”
There are, of course, differences
between the race car and production
Corvette Z06. For example, the C7.R
carries over the powertrain for the
C6.R, as the GT rules limit the
maximum displacement to 5.5L, and
prohibit forced induction. By
comparison, the new Z06 boasts a
supercharged 6.2L engine estimated
at 625 horsepower. Both engines,
however, are based on the historic
small block architecture.
The suspension on the C7.R is
modified to accommodate wider racing
tires and larger brakes, again part
of the GT regulations.
On the aerodynamic side, one
major difference is the shift away
from U.S. National Advisory
Committee for Aeronautics, or NACA,
ducts on the C7.R. The C6.R used two
NACA ducts, on top of the rear
bodywork and near the position of
the rear wheels, for cooling. For
the new C7.R, there are now openings
on each of the rear quarter panels,
above the brake ducts, which will
draw air to help cool the race car’s
transaxle and differential.
Additionally, one of the primary
results of the C7.R’s aero detail is
making the rear wing a
more-significant part of the car’s
aero package. A larger radiator
inlet has the added benefit of
generating smoother airflow over the
rear wing and making its use more
efficient to the handling and
stability of the race car at high
speed.