PONTIAC, MI –
When it was introduced at the North American International Auto Show in Detroit earlier this year,
the 2009 Chevrolet Corvette ZR1’s power was estimated at 100 horsepower for
each of its 6.2 liters of displacement. GM Powertrain has completed SAE
certification of the ZR1’s supercharged LS9 V-8 and the results exceed the
estimate: 638 horsepower (476 kW) and 604 lb.-ft. of torque (819 Nm).
The LS9’s
output is nearly 103 horses per liter, or just about 1.7 horses for each of the
engine’s 376 cubic inches. It is the most powerful automotive production engine
ever manufactured by General Motors and enables the Corvette ZR1 to achieve a
top speed of more than 200 mph (322 km/h).
“One of
the most amazing things about the Corvette ZR1 is the level of refinement that
our designers and engineers have attained. Even with all that power, this car
has road manners that will allow our customers to enjoy it on the streets as a
daily driver, and on the track,” said Chevrolet General Manager Ed Peper.
The
Corvette ZR1 goes on sale this summer. Its 638-hp supercharged engine is
complemented in the chassis by heavy-duty components not offered in any other
model, including a six-speed manual transmission with race-hardened gears and
dual-disc clutch technology that delivers exceptional clamping power and lower
inertia, as well as strengthened axle components.
Fuel
economy testing has not been completed, but engineers are confident the ZR1
will be the most fuel-efficient 600-plus-horsepower car on the market.
The LS9
engine is hand-built by specially trained technicians at GM’s Performance Build Center in Wixom, Mich.
It is a unique, small-volume engine production facility that also builds the
Chevrolet Corvette Z06’s LS7 engine and other high-performance GM production
engines.
“Developing
the LS9 involved more than simply striving for a great horsepower number.
Endurance and reliability testing have shown the engine to be robust and
low-maintenance, just like other engines in the small-block family,” said Sam
Winegarden, executive director, engine engineering for GM Powertrain. “That it
is distinguished as the most powerful engine ever from General Motors is a
source of immense pride among everyone involved with the LS9.”
The key
enabler of the LS9’s performance is the industry’s first production application
of a new, positive-displacement Roots-type supercharger that has a unique
four-lobe rotor design. Its design promotes quieter and more efficient
performance, while the large, 2.3L displacement ensures adequate air volume at
high rpm. Maximum boost pressure is 10.5 psi (0.72 bar). It is teamed with an
integrated charge cooling system that reduces inlet air temperature for maximum
performance.
“The
combination of large displacement and the new, four-lobed rotor design broadens
the effective range of the supercharger, allowing the engine to make more power
at lower rpm and sustain it throughout the power band,” said Winegarden. “The
low-end torque is tremendous and the high-rpm charge from the supercharger is
simply amazing.”
A raised
hood provides adequate clearance for the LS9, while a polycarbonate window in
the hood provides a view of the engine beneath it.
The LS9
features many unique design and manufacturing details that support its
high-performance nature. They include:
