Posted on 04/25/2008 7:24:46 AM PDT by Red Badger
When Chevrolet officially announced the new Corvette ZR1 just before the Detroit Auto Show this year, it hadn't yet finished the certification of its new power-plant, the supercharged LS9. At that time, all the engineers would tell us was that the supercharged 6.2L V8 would produce a minimum of 100hp/L or 620 hp. Three months have passed since we got our first official look at the LS9 and the numbers are now in. According to GM, the LS9 has now been SAE Certified at 638 hp and 604 lb-ft of twist. 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. Check out the articles below for all the details on the ZR1 and LS9.
CHEVROLET ANNOUCES CERTIFIED POWER RATINGS FOR THE NEW CHEVROLET CORVETTE ZR1: 638 HP FROM THE SUPERCHARGED LS9 V-8
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-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
the Vet ain’t plastic and the resale tween your choice and the Vet is light years apart
“Yay”, she exulted, “I’m the highest scoring white guy on a basketball team!”
Your asian daughter is a white guy? :-)
Hotshots upgrading from a BMW 318i will be mangling these Vettes all over the nation in the first week of ownership, guaranteed.
The Japanese make great appliance type cars but their attempts at high perf stuff (Acura NSX etc) always seem to
fade away into obscurity.
Is that 27 mpg maintained at nearly 3 times the speed limit?
the NSX could not keep front tires under her.....the last Toyota Supra was a good effort however
I think you’re correct. Six hundred thirty-eight is more horsepower than the average Joe can handle. Although I assume the car has traction control.
On another subject, the Buick had pushrod overhead valves back in 1908.
Do you remember the statistics 3 years after the Buick Grand National came out?
I remember some magazine claiming that 1/3 had been totaled and another 1/3 had been at least wrecked.
I don’t have any link, just something I remember talking about with my brother.
more than traction control.......stabililink and the pc is intergal to the motor and brakes..........literally in nano seconds an outta control wheel is brake applied automatically til the tire regains traction
OHV simply means the valves are on top. The means by which the valves are opened can be either Overhead cam (no pushrods) or in block cam via push rods.......
Ok your explanation makes perfect sense. So Overhead Cam means no pushrods.
So my next question - what information does OHV really convey? I mean way back when you had the “flathead” engines where I guess the valves were on the side???, but practically speaking, in today’s terms are any engines not OHV?
Traction control won’t make the difference. :)
“Still pushrod 1930’s technology”
I used to look down my nose at pushrod engines, but it’s hard to argue with them when they get the desired results. In the case of the domestic manufacturers’ V6 pushrod engines, they also mean that you can get a torquey V6 for what the imports charge for their 4-cyl.
My mistake; there were OHV engines before that, but they did not use high compression. The oldest design is side-valve. Still, like I said, there are advantages and disadvantages to each design. OHV can’t rev as high, but OHC is complicated and bulky.
overhead valving is not the biggest issue....by reloacting cams to the upper part of the cylinder heads push rods were replaced by cam lobes in direct location to the valves........also OHValving allowed a space to experiment with valve sizing...a plus
yes it is because of 14 hole lazer drilled injectors
OK so previous poster says that OHV is the opposite of side-valve. I guess the only engine I can think of that would match this would be the old flat-head designs. I can’t think of a modern engine that is side-valve - but maybe that’s just me.
They were in the block, to the inside of the piston, directly pushed up from the in block cam via lifters, solid or hydraulic. The cutout in the head was shaped like a silhouette of Mickey Mouse. Very low compression, like 6:1, so the overhead valve concept enabled higher compression ratios, and thus the need for higher grades of gasoline to prevent pre-ignition pings and knocks.... I>...but practically speaking, in today’s terms are any engines not OHV?
Lawnmowers...........
Got it. Thanks!
And I love every cubic inch of it.
imagine a 2x4 in your hand....a top / bottom and 2 sides
a typical 350 v8 chevy ( 1955 to 2004 ish)
had valves on the side and a horizontal action....when cams were installed in the heads,the luxury was putting the valves on top....in time valve size and number were the tricks to hp and gas mileage
the old days flathead or in-line six’s had valves on top
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