The high word is finally out, the Corvette ZR1, powered by GM's new and most powerful engine ever, produces 638 hp. The hand-built 6.2 liter LS9 supercharged V8 engine was initially estimated at 620 hp, 100 hp per liter, but has exceeded expectations with 638 hp (476 kW) and 819 Nm of torque (604 lb.-ft.)
"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 combination of large displacement and the new, four-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."
[UPDATE - 2:45pm EST] GM has sent us this excellent video which shows a top speed run at their banked oval test track in Papenburg Germany. While the ZR1 takes the high road, other vehicles testing simulataneously such as a semi trailer truck are taking the low road and seem to be stationary objects as the ZR1 rockets past. Although a little difficult to see in the video, look carefully at the digital speedometer mounted just below the air vents in the center console. Cruising at a steady 100 mph, the ZR1 shows you how quickly it can reach 205mph
CHEVROLET ANNOUCES CERTIFIED POWER RATINGS FOR THE NEW CHEVROLET CORVETTE ZR1: 638 HP FROM THE SUPERCHARGED LS9 V-8
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-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
Specifications
LS9 6.2L SUPERCHARGED V-8
- Displacement (cu in / cc): 376 / 6162
- Bore & stroke (in / mm): 4.06 x 3.62 / 103.25 x 92
- Block material: cast aluminum
- Cylinder head material: A356-T6 rotocast aluminum
- Valvetrain: overhead valve, 2 valves per cylinder
- Fuel delivery: SFI (sequential fuel injection)
- Compression ratio: 9.1:1
- Horsepower / kW: 638 / 476 @ 6500 rpm
- Torque (lb-ft / Nm): 604 / 819 @ 3800 rpm
- Fuel shut-off (rpm): 6600
- Recommended fuel: premium required
- Exhaust manifolds: stainless steel
- Main bearing caps: forged steel
- Crankshaft: forged steel
- Camshaft: hollow steel; 0.555-in (14.1 mm) lift
- Connecting rods: forged titanium
- Valves:
- intake: titanium
- exhaust: hollow steel
- Valve lifters: hydraulic roller
- Supercharger: R2300, four-lobe "Roots" type (2.3L)
- Additional features: piston oil-spray cooling; direct-mount ignition coils; 11-rib accessory drive
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