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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.

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[Source: General Motors]

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


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
overhead valve, 2 valves per cylinder
Fuel delivery:
SFI (sequential fuel injection)
Compression ratio:
Horsepower / kW:
638 / 476 @ 6500 rpm
Torque (lb-ft / Nm):
604 / 819 @ 3800 rpm
Fuel shut-off (rpm):
Recommended fuel:
premium required
Exhaust manifolds:
stainless steel
Main bearing caps:
forged steel
forged steel
hollow steel; 0.555-in (14.1 mm) lift
Connecting rods:
forged titanium
intake: titanium
exhaust: hollow steel
Valve lifters:
hydraulic roller
R2300, four-lobe "Roots" type (2.3L)
Additional features:
piston oil-spray cooling; direct-mount ignition coils; 11-rib accessory drive

[Source: General Motors]

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    • 1 Second Ago
      • 7 Years Ago
      Amazing. 638hp factory stock. I wonder how much more can be squeezed out of it with a slightly smaller pulley, heads, cam, intake, exhaust, tune, ect. Especially since most of that stuff is already out there for the 6.2L SBC. I bet we'll see 800+hp ZR-1's the week after they come out.
      • 7 Years Ago
      Mmmmm... Tire shredding torque.
        • 7 Years Ago
        Yar, if you're facts are straight as you say, then why did you suddenly change your numbers around?

        A FULLY trimmed LS7 weighs 458 lbs.
        A FULLY trimmed e92 V8 weighs 445 lbs.

        After your last comment I began to question myself, until I googled "ls7 engine weight", and every single source that popped up directly stated that the LS7 weighs ***458 lbs***. You can't compare the weight of a fully trimmed engine to that of a stripped out one.

      • 7 Years Ago
      HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit HP/L has no actual benefit

      All that matters is power, torque, rpm, weight, mpg, c.g., reliabilty, aka things you can actually feel from driving. Hp/L is simply a NUMBER.
        • 7 Years Ago
        Yep. Displacement is just a means to an end. Outside of engineering applications, it's about as exciting and meaningful as connecting rod length or intake valve height.

        The hp/l cultists would judge a tire by the number of tread blocks or a transmission by the number of blades on the torque converter.
        • 7 Years Ago
        keep telling yourself that, buddy.

        Hp per liter takes several things into account in it's ratio measurement "number"

        HP is a function of torque and engine speed, or RPMs. Liters of displacement also determines physical dimensions of the engine itself, which has some impact on engine weight.

        Fuel efficency is also somewhat a function of power and displacement, which are accounted for. It also depends on chassis weight, which is a separate issue.

        The law of diminishing returns, increases in friction, drag, inertia, and other things do come into effect and make it much more difficult for a high displacement engine to achieve a 100:1 ratio of horsepower to liters of displacement.

        It is much easier to get 100 horsepower out of 1 liter than it is to get 600 horsepower out of 6 liters, or 1000hp out of 10 liters, all other things being equal. (all or none having power adders like forced induction.)

        So there. the NUMBER, a RATIO, actually, is an assemblage of all of the various other "number" measurements you refer to. None of them are any more or less relevant than the others, it is just a matter of what is derived from what else.

        HP/Liter takes a lot into effect, and in terms of power efficiency is pretty telling. fuel efficiency is a different measurement, and is optimized in a much different way, usually at the cost of optimum power output.

        BTW, Cg is dependent on the chassis, reliability is not something you feel while the engine is running, it only matters when the engine is not running when it should be. So those don't even fit your criteria for ENGINES. and we aren't really talking about pros and cons of chassis design here.

        Keep telling yourself whatever it is you need to tell yourself that you are right, and everyone else is wrong... De-Nile is not just a river in Egypt.
          • 7 Years Ago
          Like Dan is saying, take a look at the external displacement of an LS7 engine, you will find it takes up less space than a 4.5 - 5.0L OHC engine. The only reason people even mention power/internal displacement is because it's an easy number that is readily available for all engines, it requires no real knowledge to derive that figure.
        • 7 Years Ago
        hp/liter is a completely arbitrary statistic.

        i am going to start using my favorite arbitrary engine stat, hp/camshaft

        the ls9 makes 638hp/camshaft, ferrari needs 4 cams to get there only making 162 hp/cam. now that is what i call lazy engineering. ferrari needs to start outsourcing their engines from the same place they get their shocks!

        bmw can only manage 127 hp/cam, PATHETIC! even a mustang gt gets 150 hp/cam. get your act together europe and japan. you have a lot of catching up to do.
      • 7 Years Ago
      GT-R > Z06
      GT-R SpecV > ZR1

      Doesnt matter which engine you put in it....!
      • 7 Years Ago
      • 7 Years Ago
      Chevy will sell every one of these puppies-dealerships will be happy with their $10,000-15,000 markups-gas station owners will drool as the ZR-1 owners stop by to visit 2-3 times a week; and I'll be crying in my beer CAUZ I CAN'T HAVE ONE.....
      • 7 Years Ago
      boost is an awsome thing, yall are all funny, boost can make anything better, i have buddies that have boosted vipers, vettes, and even lambos, Ford GT, all making rediculous power viper=1700rwhp, vette =968rwhp, lambo(gallardo)=900awhp, Ford GT=950+rwhp point being can make anything create more power!
      • 7 Years Ago
      "HP/Liter" does not matter!

      Tell that to the Chevy engineers who designed Formula 1 engines that are restricted by size.

      Oh wait there aren't any currently running GM Formula 1's, silly me.
        • 7 Years Ago
        you can't be serious...

        obviously hp/liter takes on some significance if THE DISPLACEMENT IS PART OF THE RACING FORMULA!

        your attempt at logic just made everyone you have ever interacted with a few IQ points

        by your exact logic, because NASCAR is limited to one camshaft, BMW and ferrari have conceded the construction of superior engines to dodge because they know they cannot compete in the HP/camshaft statistic.

        get real man

      • 7 Years Ago
      Finally something to upgrade my stretched Fiero

      GM is selling this crate right?

      j/k, but how about this in the g8?
      • 7 Years Ago
      I honestly can't say I would have imagined 25 years ago that the 'vette would be packing this kind of muscle today. Very impressive stuff.
        • 7 Years Ago
        275 hp was supercar territory. Now we see close to that in Honda minivans and hatchbacks.
        • 7 Years Ago
        There are a lot of Honda NSX and BMW M1 fans who would disagree with you. I know, since I got in arguments with them recently.

        I personally think the last supercar with 275HP was the Lotus Espirit. It was also pretty much the first car I ever heard called a supercar (although older cars have since retroactively been called this).
        • 7 Years Ago
        275 hp hasn't been supercar territory since before the second world war.

        The EPA-emasculated crap sold from the 70s through the early 90s may have had nice bodywork and prancing horses or bulls on their branding logos, but their only quality worth the superlative was 'disappointing'.

      • 7 Years Ago
      Awesome engine. Doubters are grasping at straws.
      • 7 Years Ago
      My old Gremlin's cast iron 258 six weighs well over 500lbs and made 120hp 190,000 miles ago. Can I claim it's better than the Ls9 too?
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