638! ( hummm, I guessed 640 awhile ago..cool. Insiders told me the GM computer actually tagged 684HP ..but this is the official number as it’s available to the retail public - what a treat it is!)
That’s the number of SAE-certified horsepower packed into the 2009 Chevrolet Corvette ZR1’s supercharged 6.2-liter V-8, along with 604 lb-ft of torque. The supercharger has a displacement of 2.3 liters with a maximum boost pressure of 10.5 psi. The most powerful production engine to ever come out from a GM factory boasts 103 horsepower per liter and will propel the “Blue Devil” to a top speed that is well over 200 mph…
The official EPA fuel economy testing hasn’t been finished and for people who buy a ZR1 it probably won’t matter anyway. Nonetheless, GM expects the LS9 to be the most fuel efficient 600+hp engine in the world, a dubious distinction if ever there was one. A special team of technicians will be hand-building and testing the LS9 at GM’s Performance Build Center in Wixom, Mich.
GM took measures to ensure that the engine would have reliability
comparable to the rest of the small-block family. According to GM powertrain
engine engineering executive director Sam Windgarden, “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”
———————————————-
GM PRESS RELEASE:
PONTIAC, Mich. – 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 unquestionably 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.”
Supercharged aspiration
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, 2.3-liter 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.
LS9 details
The LS9 features many unique design and manufacturing details that support its high-performance nature. They include:
Aluminum cylinder block with iron cylinder liners that are finish-bored and
honed with a deck plate installed
Forged steel crankshaft with a nine-bolt flange Titanium connecting rods and
forged aluminum pistons
Stronger, rotocast cylinder heads with 2.16-inch (55 mm) titanium intake
valves and 1.59-inch (40.4 mm) hollow-stem, sodium-filled exhaust valves
Camshaft with 0.555-inch (14.1 mm) lift for excellent idle and low-speed
driving qualities
A dry-sump oiling system with 10.5-quart (9.9 liters) capacity -Integrated oil
cooler and piston-cooling oil squirters
Intercooler cover visible through the hood window that features ZR1-unique
blue accents and “LS9 SUPERCHARGED” embossed on the left and right sides
