2010 LS3 6.2L V-8 (LS3)

6.2L V-8 (LS3) CAR ENGINE
2010 Model Year Summary

New product applications, content and benefits for 2010 model year:

• Standard engine in the new Camaro SS
• New model offering in Corvette Grand Sport Coupe and Convertible
• Includes new dry sump oiling system on 2010 Corvette Grand Sport coupe with manual transmission
• Gen IV aluminum cylinder block
• High-flow cylinder heads derived from the LS7 engine
• High-flow intake manifold with acoustic shell
• High-flow fuel injectors
• Advanced electronic throttle control
• 58X ignition system
• Acoustic beauty cover

New engine offering in the Chevrolet Camaro SS
The LS3 V-8 is the base engine for the 2010 Corvette and the new Camaro SS. In the Corvette it is rated at 430 horsepower (321 kW), or 436 horsepower (325 kW) when equipped with the optional dual-mode exhaust system (RPO NPP). In the Camaro SS, the engine is rated at 426 horsepower (318 kW). The LS3 is offered with the Hydra-Matic 6L80 six-speed automatic or a Tremec six-speed manual transmission (with specific gearing for the Grand Sport models). With the Camaro, the LS3 is only offered with a Tremec six-speed manual transmission; automatic-equipped SS models are paired with the 6.2L L99 engine that features Active Fuel Management. See the separate L99 release for more information.

Dry sump oiling system
New for 2010 in Corvette Grand Sport coupe models equipped with the manual transmission, the LS3 with the Z52 option features a dry sump oiling system that is similar to the oiling systems used in the Corvette Z06 and ZR1 models. The dry sump oiling system helps the LS3 engine operate at peak, low-friction efficiency and promotes durability during extended high-rpm use under high cornering loads. The Grand Sport coupe’s unique suspension system is designed for track use and is capable of generating 1-g cornering, which is greater than the standard Corvette.

The dry sump system scavenges engine oil from the engine utilizing the first stage of the dual-stage gerotor oil pump. Oil and air are collected from the bottom of the engine oil pan and then transported to the external engine compartment mounted reservoir for conditioning and storage. Oil is transported to the top of the tank through an internal scavenge return tube, where it is tangentially spilled out on a spiral-shaped internal baffle. When the aerated oil from the engine contacts the internal surfaces of the tank, crankcase gasses and air which are entrained in the oil are separated out. These gasses are directed by the PCV system through a series of baffles and tubes back to the crankcase and into the combustion chamber to be burned. The de-aerated oil is directed down the walls of the tank to collect in the 10.5-quart (9.9 liters) reservoir, conditioned and ready for use. The second stage of the dual-stage gerotor pump then draws the conditioned oil from the tank and pressurizes it, feeding it to the engine via the oil filter and oil cooler. The routing of the engine oil to and from the dry sump reservoir also provides the benefit of passive oil cooling.


Gen-IV Cylinder Block
The LS3 6.2L’s Gen-IV cylinder block shares two key design elements with GM’s original small block V-8: a 90-degree cylinder angle and 4.400-inch bore centers. It debuted in 2005 as the foundation for the 400-hp LS2 V-8 in the Chevrolet Corvette and Pontiac GTO. Casting and machining in the bulkheads was revised to improve block structure and to improve bay to bay breathing; the bores were also increased from 4.00 inches (101.6 mm) to 4.06 inches (103.25 mm) to increase the engine’s displacement. The enhanced cylinder block casting is shared with the 6.2L truck applications and the 6.2L supercharged LSA and LS9 applications.

The Gen IV block was developed with the latest math-based tools and data acquired in GM’s racing programs, and provides a light, rigid foundation for an impressively smooth engine. Its deep-skirt design helps maximize strength and minimize vibration. The bulkheads accommodate six-bolt, cross-bolted main-bearing caps that limit crank flex and stiffen the engine’s structure. A structural oil pan further stiffens the powertrain.

High-Flow Cylinder Heads and Valvetrain
The rectangular intake port shape size and shape are similar to the L92 6.2L – a designed that has its origins in the LS7 cylinder head, but with a taller and narrower port configuration. Casting changes were made to increase the opening at the exhaust face to improve exhaust port flow.

The inlet rocker arm is offset 6 mm between the valve tip and rocker bolt/push rod to enable a more direct intake port. The intake valve diameter is 55 mm; and hollow-stem intake valves are used to enable high-rpm performance of up to 6,600 rpm. The 40.4-mm exhaust valves are carried over from L92, as are high-load valve springs that stand up to the engine’s high-rpm capability. Intake valve lift increases is 0.551-inch (14 mm).

High-flow intake manifold with acoustic shell
The LS3’s intake manifold ports are designed to match cylinder head. The composite manifold is manufactured with a lost core process to improve runner-to-runner variation and to reduce flow losses. Acoustic foam is sandwiched between the outside top of the intake manifold and an additional “skull cap” acoustic shell to reduce radiated engine noise. Structural enhancements have been added to the manifold bosses.

High Flow Injectors
High-flow, 5.0 g/s injectors are the same as those used on the 7.0L LS7 engine.

Advanced Electronic Throttle Control
GM has led the industry in applying electronic throttle control (ETC). With ETC, there is no mechanical link between the accelerator pedal and the throttle body. A sensor at the pedal measures pedal angle and sends a signal to the engine control module (ECM), which in turn directs an electric motor to open the throttle at the appropriate rate and angle. ETC delivers a number of benefits to the customer. With the ECM measuring throttle pedal angle and monitoring other data including the transmission’s shift status and traction at the drive wheels, the ETC system can deliver outstanding throttle response and greater reliability than a mechanical connection, which typically uses a cable that requires adjustment—and sometimes breaks. Cruise control electronics are integrated into the system, further improving reliability and simplifying engine assembly.

58X Ignition System
The LS3 6.2L engine has an advanced 58X crankshaft position encoder to ensure that ignition timing is accurate throughout its operating range. The new 58X crankshaft ring and sensor provide more immediate, accurate information on the crankshaft’s position during rotation. This allows the engine control module to adjust ignition timing with greater precision, which optimizes performance and economy. Engine starting is also more consistent in all operating conditions.

In conjunction with 58X crankshaft timing, the LS3 applies the latest digital cam-timing technology. The cam sensor is located in the front engine cover, and it reads a 4X sensor target on the cam sprocket. The target ring has four equally spaced segments that communicate the camshaft’s position more quickly and accurately than previous systems with a single segment.

The dual 58X/4X measurement ensures extremely accurate timing for the life of the engine. Moreover, it provides an effective back-up system in the event one sensor fails.

Acoustic Beauty Cover
The beauty cover is specific to each vehicle model, but is designed to contribute to the acoustic properties of the engine.

Overview
The LS3 6.2L engine delivers a great balance of performance and efficiency. The engineering team used years of development experience with both production-vehicle and racing applications of the Gen III/Gen IV engine design to optimize flow efficiency to build power and improve fuel economy. In fact, the 2010 Camaro SS delivers and EPA-rated 24 mpg on the highway with the LS3/six-speed manual combination; and the 2010 Corvette offers up to 26 mpg on the highway with the manual transmission. That’s the same highway mileage rating as the 2005 Corvette that had a less-powerful and smaller-displacement 6.0L engine.

One of keys to the LS3’s efficiency is great airflow throughout. Intake flow was improved over previous engines by straightening out and optimizing the flow path from the intake manifold into the cylinder heads, while the exhaust ports are also designed for greater flow. The engine’s efficiency also enhances emissions performance, as the LS3 meets the more stringent Bin4 emission standards and again avoids the gas guzzler tax on the Corvette and Camaro.

2010 "LS9" 6.2L V-8 SC (LS9)
2010 Model Year Summary

 Carryover Gen IV Small-Block V-8 for 2010 Chevrolet Corvette ZR1
 Gen VI Supercharger with Twin Four-Lobe Rotors
 Integrated Dual-Brick Air-to-Liquid Intercooler
 Enhanced Gen IV Cylinder Block
 Forged-Aluminum Pistons with Oil-Spray Cooling
 Lightweight Reciprocating Assembly with Titanium Connecting Rods
 Refined Low Overlap Cam
 High-Flow Rotacast Cylinder Heads with High Performance Valves
 Center-Feed Fuel System
 Direct-Mount Ignition Coils
 E67 Control Module
 Dry-Sump Oiling System
 Heavy-duty Accessory Drive
 Stainless Steel Exhaust Manifolds with Close-Coupled Catalysts
 Acoustic Engine Cover

Full Description of Carryover Features and Benefits

Carryover Gen IV Small-Block V-8 from 2009 MY for 2010 Chevrolet Corvette ZR1
The 638-hp 6.2L Supercharged V-8 (RPO LS9) is installed longitudinally in the Corvette ZR1, and offered only with the twin-disc Tremec TR6060 six-speed manual transmission. This engine is hand-assembled at GM's Performance Build Center in Wixom, Mich.

Simply put, the supercharged LS9 is the most powerful production engine ever offered by GM --a company with over a 100-year tradition of building very powerful engines. The LS9 generates 638 horsepower at 6500 rpm and 604 pound-feet of torque at 3800 rpm, certified by the Society of Automotive Engineers. Its specific output of 103 horsepower per liter, or 1.70 horsepower per cubic inch, is remarkable for an engine of its displacement. According to published figures, the LS9-equipped ZR1 has more horsepower and torque than the Dodge Viper SRT10, Ferrari 599 GTB Fiorano, and Porsche 911 GT2 Lamborghini Murcielago LP640- all benchmarks among exotic international sports cars.

Yet, thanks to its advanced engineering, the LS9 is civil at low speeds and remarkably tractable at all speeds. It idles with the smoothness of a luxury-car engine and generates 350 lb-ft of torque at just 1000 rpm, with 90 percent of its peak torque available from 2600 rpm to 6000 rpm. In short, the 6.2L Supercharged LS9 takes the combination of tremendous low-end pull and excellent high-rev horsepower that has long characterized Corvette small-block V-8s and extends it to an unprecedented level.

Gen IV Supercharger with Twin Four-Lobe Rotors
State-of-the-art supercharging technology is one key to the 6.2L LS9's remarkable performance. This Gen IV V-8 represents the first original-equipment application of Eaton's twin-rotor R2300 supercharger-one of the company's Twin Vortices Series (TVS), which introduce the sixth generation of joint Eaton/GM supercharger development. The LS9 supercharger displaces 2.3 liters, compared to more conventional superchargers of 1.5 liters or less, and generates maximum boost pressure of 10.5 pounds per square inch (0.72 bar).

A supercharger is essentially an air pump driven by the engine's crankshaft. It forces more air into the engine's combustion chambers than that engine could otherwise draw on its own. The increased volume of oxygen allows the engine to efficiently process more fuel, and thus generate more power.

The TVS takes supercharging technology to new levels of refinement and efficiency. Each of its two rotors has four distinct lobes, or spiral-shaped vanes that intermesh precisely with those on the other rotor as they spin at high speed. Efficiency gains with the four-lobe rotors are substantial, compared to comparably sized, previous-generation superchargers: approximately 20 percent more airflow, with an improvement in thermal efficiency up to 15 percent. Moreover, parasitic power loss-the amount of power the engine uses to operate the supercharger-is reduced 35 percent. That improves both supercharger response time and the engine's overall efficiency.

With the LS9, the numbers speak for themselves: 103 horsepower per liter displacement, with substantially higher specific torque than comparably sized engines from Ferrari and Lamborghini. Yet impressive output figures tell only part of the story.
The TVS supercharger's large displacement expands its effective range, building power more quickly at low rpm. Its four-lobe rotors spin at up to 15,000 rpm, or slightly more than twice the engine's rotation speed, to sustain its benefits at high engine speeds, when many superchargers lose their effectiveness. There's no high-rev power drop-off in the LS9.

Nor is there typical supercharger whine-the high-pitched, whizzing sound emanating from a supercharged engine as the rotors spin furiously. The four-lobe design helps lower noise radiating from the supercharger case as much as 10 decibels. Sound pressure is nearly identical whether or not the supercharger is generating boost.

The R2300 supercharger case and integrated intercooler have been tailored to the space available in the Corvette's engine bay. Despites its relatively large displacement, the supercharger sits neatly atop the 6.2L LS9 under a slight, see-through bulge in the ZR1's carbon-fiber hood. The air inlet and drive pulley are located at the front of the case, and the LS9's overall height is only slightly taller than the standard Corvette LS3 V-8.


Integrated Dual-Brick Air-to-Liquid Intercooler
An advanced intercooling system increases the 6.2L LS9's performance and extends its supercharger's benefits. The engine's charge cooler is integrated in the supercharger case just above the rotors, with two air-to-liquid cooling "bricks" that substantially lower the temperature of air used in the combustion process.

Intercoolers are familiar features on supercharged and turbocharged engines. Similar in concept to an engine's radiator, intercoolers cool the air pumped by the charging device into the cylinders. Cooler air is denser air, which means more oxygen in a given volume, resulting in optimal combustion and more power. Traditionally, intercoolers look like small radiators mounted somewhere outside the engine, with air fed into the engine through a plumbing network.

The LS9's intercooling system raises the bar in both packaging and efficiency. It uses two low-profile, aluminum tube-and-fin heat exchangers mounted longitudinally above the rotors in the supercharger case. Air pumped by the supercharger flows directly through these bricks to the intake ports on the cylinder heads. The bricks are cooled by their own coolant circuit, with a remote pump and 3.62-liter capacity heat exchanger mounted in front of the Corvette's radiator.

Bottom line: The temperature of air fed to the LS9's cylinder heads is reduced 140 degrees F (60 degrees C), substantially increasing the amount of oxygen available for the combustion process. The intercooler design also contributes to the supercharger's quiet operation. The cooling bricks help dampen sound radiating from the supercharger case, while ribs cast into the top of the intercooler housing add strength and reduce vibration.

Enhanced Gen IV Cylinder Block
The 6.2L Gen IV small block has been further refined for the LS9. It's cast from 319-T7 aluminum and fitted with cast-iron cylinder liners

Bulkheads in the LS9 engine block have been strengthened 20 percent by optimizing the size of the bulkhead "windows" to take advantage of material thickness in the bulkhead. This is additional improvement beyond a 20% gain obtained in the naturally aspirated 6.2L LS3 V-8 by increasing the radius of the hone over-travel fillets from three to 10 millimeters. The enlarged bulkhead windows also improve bay-to-bay breathing by managing airflow inside the engine more efficiently, thereby decreasing pumping loss, or reducing resistance to the pistons' downward movement.

Bulkheads are the structural elements that support the crank bearings. In the LS9, they accommodate six-bolt, cross-threaded main-bearing caps that limit crankshaft flex and stiffen the engine's structure. The caps are forged steel, fully machined on all surfaces and dowel aligned for precise fit and minimal vibration.

The cylinder liners are cast in the LS9 block and machined with a deck plate installed over the cylinder bores. The deck plate simulates the pressure and tiny dimensional changes that occur when the cylinder heads are bolted to the block. The process enhances assembly quality and fit, ensuring precise head sealing, improved piston ring sealing and peak performance as the engine accumulates miles.

Block enhancements initiated with the LS9 will be applied to all 6.2L Gen IV engine blocks, including those used for the new LSA in the 2009 Cadillac CTS-V, the LS3 Corvette V-8 and truck applications. While the Gen IV block shares its 90-degree cylinder angle and 4.4-inch bore centers with GM's original small block V-8, it applies design, casting and machining technologies that were unfathomable when the original was introduced in the 1950s.

The Gen IV block debuted in 2005 as the foundation for the 400-hp LS2 V-8 in the Chevrolet Corvette, Cadillac CTS-V and Pontiac GTO. It was developed with the latest math-based tools and data acquired in GM's racing programs, and it provides an exceptionally light, rigid foundation for an impressively smooth cam-in-block engine. Its deep-skirt design helps maximize strength and minimize vibration, and its aluminum construction reduces weight approximately 100 pounds compared to a conventional cast-iron cylinder block.

Forged-Aluminum Pistons with Oil-Spray Cooling
Superior piston design sets the tone all of the 6.2L LS9's internal components. The engineering objective? Lighter, stronger and smoother.

The pistons themselves are aluminum-not cast, but forged, for a high-performance combination of low mass, high strength and durability. These are considerably lighter than conventional aluminum pistons, which translates to less reciprocating mass inside the engine. Less mass means greater efficiency, high-rpm capability and a feeling of immediate response as the engine builds revs.

The combustion surface of the LS9 pistons, or the crown, lacks the valve-relief pockets typical on high-performance engines with relatively high-lift valves. Rather, the LS9 crown is sumped, with a saucer-shaped indent that dips gradually from the outer edge of the piston. This design promotes a thorough mixing of air and fuel and, with other durability enhancing features such as an anodized top ring groove, allows a 9.1:1 compression ratio: higher than a conventional supercharged or turbocharged engine, for improved combustion efficiency.

The anodized top ring groove reduces wear and accepts the heat generated during combustion between the top ring and its groove. To further reduce wear, the piston skirt is coated with a polymer material, which eliminates bore scuffing, or abrasion of the cylinder wall over time from the piston's up-down motion. The polymer coating also dampens noise generated by the piston's movement. The wrist pins, which attach the piston to the connecting rod, were developed for maximum durability, with a large outer diameter and a tapered inner diameter. These pins "float" inside the rod bushing and pin bores in the piston barrel. Compared to a conventional fixed pin assembly, in which the connecting rod is fixed to the piston's wrist pin and the pin rotates in the pin bore, the floating pins reduce stress on the pin. They allow tighter pin to pin-bore tolerances and reduce noise generated as the piston moves through the cylinder. The benefit is less engine wear, improved durability and quieter operation.

Finally, the 6.2L LS9 represents the first line of small block V-8s equipped with oil-spray piston cooling. Eight oil-squirting jets in the engine block drench the underside of each piston and the surrounding cylinder wall with an extra layer of cooling, friction-reducing oil. The oil spray reduces piston temperature, promoting extreme output and long-term durability. The extra layer of oil on the cylinder walls and wristpin also dampens noise emanating from the pistons.

Lightweight Reciprocating Assembly with Titanium Connecting Rods
Careful analysis applied to the pistons extends to other reciprocating components inside the 6.2L LS9 V-8. Whenever possible, GM has trimmed mass, increased strength and reduced friction, enabling the LS9's high-rpm capability, improving overall performance and working to ensure durability.

Within the LS9's cylinder block spins a balanced, dropped-forged micro-alloy steel crankshaft with a nine-bolt flange to mount the flywheel. The nine-bolt pattern increases clamping strength compared to naturally aspirated 6.2L Gen IV V-8s, which use a six-bolt crank flange. A smaller-diameter ignition-timing reluctor wheel trims weight and ensures clearance to the pistons as they move in the bore. At the front end of the crank, the torsional damper is secured with a keyway and friction washer for an added element of security, given the LS9's exceptional torque.

Titanium connecting rods mate the crank with the pistons, for the ultimate combination of strength and light weight. The titanium rods weigh roughly 25 percent less than conventional iron or steel. They reduce pressure on both the rod-end bearings and main bearings, and allow the bearings to be optimally sized for the least amount of friction.

Refined Low Overlap Cam
A refined camshaft helps balance the 6.2L LS9's remarkable output with silky, tractable low-rev operation.

The camshaft operates the engine's valves, and its design is crucial to both power and smoothness. The torque enhancing benefits of the supercharger allowed GM engineers to develop a "softer," lower-lift camshaft for the LS9, compared to the typical high-rev, high-power exotic car engine. The LS9 cam delivers maximum lift of 14.3 mm for the intake valves and 14.2 mm for the exhaust valves. Moreover, the cam lobes are profiled to reduce the amount of time that both intake and exhaust valves are partially open at the same time. Valve overlap is reduced 27 percent compared to the track-bred 7.0L LS7 V-8 in the Corvette Z06. The result is smoother operation at low speeds, and particularly at idle. Idle quality improves 11 percent compared to the LS7.

High-Flow Rotacast Cylinder Heads with High Performance Valves
The 6.2L Supercharged LS9 cylinder heads are similar to those used on the naturally-aspirated 6.2L LS3 Corvette V-8, with enhancements for supercharged induction and maximum durability.

The LS9 heads feature a unique "wing'' cast into each intake port to promote a swirling motion that blends the pressurized air-fuel charge. The heads are also cast from a premium A356T6 alloy, which better manages the heat generated in a supercharged engine. A356T6 pays particular dividends in the thin bridge area between the intake and exhaust valves, where effective heat dissipation is crucial to both performance and long-term durability. Finally, the LS9 heads are rotacast. This process rotates the head mold as the molten alloy cools and essentially eliminates porosity, or microscopic pockets of air trapped in the casting. Rotacasting delivers a stronger part that helps maintain performance and structural integrity over the life of the engine.

Low-friction hydraulic roller lifters actuate the LS9's valves, with unique offset rocker arms for the intake valves. On the inlet rocker, the valve tip is offset six millimeters from the pushrod. This configuration allowed GM engineers to locate the intake port for a more direct air-fuel flow into the combustion chamber.

Intake valves measure 55 mm in diameter and are fabricated from titanium-chosen for its combination of strength, light weight and high-rpm potential. Perhaps more crucial to durability are the exhaust valves, which are typically the hottest part in the engine. Those in the LS9 measure 44.0 mm in diameter, and they're manufactured from a high-chromium steel alloy called SilChrome 1, with hollow, sodium-filled stems. At normal operating temperatures, the sodium inside the valve stem melts and becomes liquid. The liquid sodium improves conductivity, promoting heat transfer away from the valve face to the cooler end of the stem, where it more readily dissipates through the valve guide. This maintains a lower, more uniform valve temperature, reducing wear on the valve seat for a consistent seal between the valve and head over the life of the engine.

Given the LS9's pressurized induction, GM's engineers focused special attention on sealing. Head gaskets are extra-robust, four-layer stainless steel, and the 12 mm cylinder head bolts are hardened stainless. The 12 mm bolts increase head-gasket clamp strength (compared to 11 mm bolts on other small block engines), ensuring gasket sealing under the high combustions pressures generated by the LS9





Center-Feed Fuel System
The 6.2L LS9's fuel system was developed to deliver adequate fuel volume precisely consistently and quietly.

To ensure appropriate fueling in all conditions, from casual cruising to race track-type wide-open throttle, GM has equipped the LS9 with a dual- pressure fuel system. The system delivers 250 kPa (about 36 psi) at idle or low speeds. Yet the electronic throttle management system can almost instantaneously increase fuel pressure to 600 kPa for sustained high-speed operation or wide-open throttle. The dual-pressure system reacts according to throttle application, and presents several advantages. It limits the energy used by the fuel pump at low speeds, for maximum efficiency, and it reduces operational noise. It also ensures adequate fuel delivery when the LS9 demands its maximum flow rate of 58 grams per second.

The LS9 also employs a new center-feed fuel rail that delivers gasoline to the center of the injector rail an each bank. The delivery point is roughly equidistant to each of the injectors, which have a maximum flow rate of 6.52 grams per second at 400 kPa. Fuel pressure variation among the injectors is reduced, and so is noise. The rapid ticking sound often generated by fuel injectors is alleviated.

An 87-mm, single-bore throttle body draws air into the engine. The electronic throttle maps have been optimized for excellent response and modulation in a multitude of driving scenarios.

Direct-Mount Ignition Coils
The 6.2L LS9's coil-on-plug ignition features advanced coils developed for the 7.0L LS7 V-8 in the Corvette Z06. These coils are smaller and lighter than those used on previous small-block V-8s. An individual coil for each spark plug delivers maximum voltage and consistent spark density, with no variation between cylinders.

The LS9 ignition system is unique nonetheless, as the coils mount directly on LS9-specific rocker covers. Those on the LS3 and LS7 are joined by a bracket. The individual LS9 coils provide a cleaner look and a shorter lead between the coil and the iridium-tip, center-electrode spark plug.

E67 Control Module
An advanced controller manages the multitude of operations that occur within the 6.2L Supercharged LS9 V-8 every split second. The E67 is the high-line controller in GM's family of three engine control modules (ECM), which was developed to direct nearly all the engines in GM's line-up. It features 32-bit processing, compared to conventional 16-bit processing, with 32 megabytes of flash memory, 128 kilobytes of RAM and a high-speed CAN bus. The E67 synchronizes more than 100 functions, from spark timing to cruise control operation to traction control calculations, and it has more computing power than the typical desktop PC 20 years ago. It works more than 50 times faster than the first computers used on internal combustion engines in the late 1970s, which managed five or six functions.

The family strategy behind GM's ECMs allows engineers to apply standard manufacturing and service procedures to all powertrains, and quickly upgrade certain engine technologies while leaving others alone. It creates a solid, flexible, efficient engine-control foundation, freeing engineers to focus on innovations like the LS9’s advanced supercharging technology and get them to market more quickly. GM creates all the software for the three ECMs, which share a common language and hardware interface that's tailored to each vehicle.

The E67 also applies a new, rate-based monitoring protocol sometimes known as run-at-rate diagnostics. Rate-based diagnostics improve the robustness of the Onboard Diagnostics System (OBD II) and ensure optimal performance of emissions control systems. The software increases the frequency at which the ECM checks various systems, and particularly emissions-control systems such as the catalytic converter and oxygen sensors. Rate-based diagnostics more reliably monitor real-word operation of these systems, and allow regulatory agencies to more easily measure and certify emissions compliance. With the E67, the Corvette ZR1's environmental performance matches its race-track potential.

Dry-Sump Oiling System
To ensure peak, low-friction efficiency, and to promote durability during extended high-rpm use under high cornering loads, the 6.2L Supercharged LS9 is equipped with a racing-style dry sump lubrication system and dual-gerotor oil pump. The first stage of the pump scavenges the small sump under the engine and delivers oil to a remotely mounted reservoir. The second stage collects oil from the reservoir and sends it under pressure to the engine. The oil cools slightly in the reservoir, and then cools again in an air-to-oil cooler after it is collected by the second stage of the pump.

The LS9's dry-sump system was introduced on the 7.0L LS7 V-8 in the Corvette Z06. But because the 2009 Corvette ZR1 further pushes the impressive performance envelope established by the Z06, the LS9 extends the system's lubricating capability 33 percent. This is accomplished with a larger 10.5-quart reservoir capacity, increased with a 2.5-quart auxiliary tank attached to the main reservoir, and higher-flow, 32.5-gpm gerotor pump. The increased capacity dry sump system will also be used on the 2010 LS7.
The dry sump system scavenges engine oil from the engine utilizing the first stage of the dual stage gerotor oil pump. Oil and air are collected from the bottom of the engine oil pan and then transported to the external engine compartment mounted reservoir for conditioning and storage. Oil is transported to the top of the tank through an internal scavenge return tube, where it is tangentially spilled out on a spiral-shaped internal baffle. When the aerated oil from the engine contacts the internal surfaces of the tank, crankcase gasses and air which are entrained in the oil are separated out. These gasses are directed by the PCV system through a series of baffles and tubes back to the crankcase and into the combustion chamber to be burned. The de-aerated oil is directed down the walls of the tank to collect in the 10 quart reservoir, conditioned and ready for use. The second stage of the dual stage gerotor pump then draws the conditioned oil from the tank and pressurizes it, feeding it to the engine via the oil filter and oil cooler. The routing of the engine oil to and from the dry sump reservoir also provides the benefit of passive oil cooling.

Corvette ZR1s will leave the Bowling Green assembly plant with crankcases filled with 30W Mobil 1 Synthetic X.

Heavy-duty Accessory Drive
To tailor the 6.2L LS9 to the Corvette's engine bay, the supercharger drive is integrated into the main accessory drive system. The LS9's two-belt accessory drive has one belt turning the air conditioning compressor and alternator, and another operating power steering, the water pump and the supercharger.

The supercharger requires the most force to turn, so its circuit uses a wider, 11-rib belt. To compensate, the LS9 water pump has improved bearing capacity. Bearing diameter is increased from 16 mm to 19 mm, compared to the LS7. To allow a common power steering pump with other small blocks V-8s, the LS9 pump is spline driven through a bracket and bearing system that takes the load of the supercharger.


Stainless Steel Exhaust Manifolds with Close-Coupled Catalysts
The 6.2L LS9 exhaust manifolds are constructed of stainless steel and designed on the principal that low restriction and less pumping loss equals more horsepower and torque.

Each manifold consists of four tubes hydroformed from 309 stainless. At its inlet, each tube starts as a D shape; from there the D varies in a complex shape that controls cylinder-to-cylinder pumping losses and keeps airflow restriction to a minimum. Analytical data was used to determine the proper sizing and length of the pipes, which come together at a wide-mouth collector that directs the exhaust flow into a catalytic converter. Hydroforming technology was required to produce the sophisticated internal geometry in each tube.

The four exhaust tubes and a stamped jacket of 304 stainless are MIG welded to an inlet flange that connects the manifold to the cylinder head. Because the tubes are welded only on one end, they're able to "float" inside the jacket and expand and contract freely as the engine heats up and cools. The floating design promotes long term durability.

The manifolds are fitted with a pair of close-coupled catalytic converters that heat quickly, achieving light-off temperature and closed-loop operations in seconds.

Acoustic Engine Cover
The LS9 is finished with a special engine cover surrounding the intercooler and supercharger case, which is visible through the ZR1's carbon-fiber hood. The intercooler cover has "LS9 SUPERCHARGED" script on each side, with the classic, crossed-flag Corvette emblem front-and-center on the engine cover.

The engine cover does more than look good. It helps isolate high-frequency sounds emanating from the engine, and it's attached with ball-stud mountings that more effectively limit vibration transfer than conventional twist-in fasteners.


Overview
The 6.2L Supercharged Gen IV LS9 V-8 is an amalgamation of performance superlatives: the most powerful production engine in GM's 100-year-history; specific output of 103 horsepower per liter; horsepower-per-kilogram or cubic meter ratios to match the most sophisticated high-performance engines in the world: more power and torque than the best production engines from Ferrari, Lamborghini and Porsche.

Measured by the cost-to-performance ratio engineered into the Corvette ZR1, the LS9 might also be considered a relative bargain. The elegant simplicity in the small-block V-8's DNA means cost-effective development and production, and that translates to value, for customers and the corporation. Yet an emphasis on value overlooks one significant point. The LS9 is one of the best high-performance V-8s in the world, regardless of price.

GM's 90-degree small-block car engines remain unique in the automotive world: high-tech, aluminum-intensive, ultra-high-performance cam-in-block V-8s. The LS9 adds a supercharger to the mix, and pushes the combination of impressive low end torque and free-breathing, high-rpm horsepower to a new level.

The starting point for the LS9 was the first engine built for the sixth-generation Corvette-the Gen IV 6.0L LS2 V-8. The LS2, in turn, had built on two milestone engines: the LS1 and LS6 V-8s developed for the C5 Corvette. Those Gen III engines had introduced a host of leading-edge technologies to the grand tradition of the Chevrolet small block V-8, starting with all-aluminum construction, a thermoplastic intake manifold and drive-by-wire electronic throttle. With them the engineers and analysts who claimed cam-in-block engines could not meet the performance demands of a new millennium--or increasingly stringent emissions standards-were proven patently wrong.

Within this evolution, and the data base only tradition can provide, rests the cornerstone of small-block value. The performance in the LS9 comes with 76 percent carryover parts from other small-block V-8s, and 25 percent of the new parts are common to the supercharged LSA V-8 for the 2009 Cadillac CTS-V. The value is enhanced by GM's advanced application of math-based computer tools. GM engineers created 370 different power simulations to optimize the LS9 and LSA. One simulation takes 24 hours, while one engine build takes nine weeks. Both the LS9 and LSA V-8s met power requirements out of the box. It's value without compromise, in performance, emissions or customer satisfaction.

On quality and durability. The 6.2L Supercharged LS9 has been validated beyond 100,000 miles and accumulated more the 6,800 hours of dynamometer testing. It has run over 100 consecutive hours at wide-open throttle without a failure. It's been road tested in the world's extreme climates and track-tested under racing g loads on some the world's most demanding circuits. It has completed actual and simulated 24-hour track tests.

If its output and high-speed potential seem to suggest otherwise, the LS9 nonetheless requires minimal maintenance. Its advanced iridium-core spark plugs and Dexcool coolant are validated to 100,000 miles of operation, with the same level of performance at 90,000 miles as they deliver at 10,0000. The LS9 also features GM's advanced Oil Life System. This technology measures stress on the engine and calculates oil life based on real-world use--whether it's profiling or severe-duty track time--rather than a predetermined mileage interval. The Oil Life System eliminates unnecessary oil changes in vehicles that are driven in light-duty conditions.

For all the improvements and advanced technologies built into the 6.2L Supercharged LS9 V-8, the bottom line still counts most. This is an ultra-high performance engine, with capabilities suited to one of the best performing sports cars in the world.

2010 "LS7" 7.0L V-8 ( LS7 )

7.0L CORVETTE V-8 (LS7) CAR ENGINE

Carryover features and benefits from 2009 model year

Overview
The 7.0L LS7 V8 is a bundle of superlatives: the most powerful production small-block V8 ever; ditto the highest operating speed (rpm) ever; more torque than the high-performance V10 in Porsche's Carrera GT or the V12 in Ferarri's 575M Maranello.

In an emotional sense, the LS7 connects the Corvette to its glorious past. Its 7.0-liter displacement translates to 427 cubic inches, identical to one of the most revered engines in racing and automotive lore-the original 427 Corvette big block. In a cold factual sense, the LS7 delivers a combination of attributes few engines-perhaps no engine--can match. It combines very high horsepower, torque and world-class race track performance with refined, tractable, rock steady operation on the street. Measured by mass, package size, performance or cost to the customer, the LS7 V8 meets or surpasses the best overhead cam V8s in the world.

The starting point for the LS7 was the first engine built for the fifth-generation Corvette-the Gen IV 6.0L LS2 V8. The LS2, in turn, had built on two milestone engines: the LS1 and LS6 V8s developed for the C4 Corvette. Those Gen III engines had introduced a host of leading-edge technologies to the grand tradition of the Chevrolet small block V8, starting with all-aluminum construction, a thermoplastic intake manifold and drive-by-wire electronic throttle.

The LS7 development team applied a number of design elements and technologies introduced and validated in the Corvette C5R road-racing program. To increase displacement, both bore and stroke were increased compared to the LS2--104.8 mm and 101.6 mm, respectively, versus 101.6 mm and 92.0 mm of the 6.0L Corvette V8. As a result, the LS7's cast iron cylinder sleeves are pressed into, rather than cast in, the aluminum engine block. LS7 pistons feature tapered wrist pins to reduced weight. The piston rings are anodized to reduce blow-by and friction, while the skirts are coated with a polymer material to limit bore scuffing and reduce noise. Titanium connecting rods weigh 464 grams each or 27 percent less than the rods in the 6.0L LS2. The lighter rods reduce the pressure on the rod end bearings and the main bearings, and allow the bearings to be optimally sized for the least amount of friction. Six-bolt, doweled-in, forged steel main bearing caps hold the balanced crankshaft in place and reduce crank flex. The weight trimming, friction-reducing features in the LS7's bottom end lower reciprocating mass and contribute to its 500-rprm maximum speed increase (7100 rpm fuel shut-off) compared to the LS2.

The old hot-rodding axiom about air in, air out applies to the LS7. The extra displacement would mean little in terms of horsepower if the engine could not draw in and then expel enough air to take advantage. To that end the LS7 is fitted with all-new cylinder heads. Fully CNC-machined intake and exhaust ports and combustion chambers reduce flow restrictions; the high machining consistency also allows a higher compression ratio. Valve angles are decreased to 12 degrees, compared to 15 degrees in the 6.0L LS2. The rocker arm ratio increases from 1.7:1 to 1.8:1 ratio. Low-friction hydraulic roller lifters actuate the valves, operated by the highest lift cam in Powertrain's production vehicle inventory. Valves are larger and taller than those in the LS2, with titanium intake valves and hollow stem, sodium-filled exhaust valves to optimize heat transfer away from the valve face.

The intake system benefits from similar part-by-part review and refinement. The result is a 20-percent decrease in flow restriction compared to the LS2. The LS7 intake manifold is three-piece friction-welded composite, with large straight intake runners designed to maintain fast airflow velocity. Maximum air-flow volume increases 18 percent over the LS2. The filter element is supplied by Donaldson Company, Inc., known for high-performance racing filters.

The exhaust manifolds are stainless steel-slipperier and lighter than cast iron-hydroformed into a unique 4-into-1 collector designed to maximize flow. Exhaust pipes on the LS7-equipped Corvette Z06 are three-inches in diameter, compared to the 2.5-inch pipes on Corvettes built with the 6.0L LS2. The LS7 mufflers contain a butterfly valve that opens at high exhaust flow levels and by-passes the "tri-flow" S-shaped path the exhaust gases normally follow. This reduces exhaust restriction, yet allows the Corvette Z06 to hum at a more muted burble during part-throttle operation (or typical back-and-forth driving).

To ensure the 7.0L LS7 V8 operates at peak, low-friction efficiency, and to promote durability during extended high-rpm use under high cornering loads, the engine is equipped with a racing-style dry sump lubrication system and dual-gerotor oil pump. The dry sump system scavenges engine oil from the engine utilizing the first stage of the dual stage gerotor oil pump. Oil and air are collected from the bottom of the engine oil pan and then transported to the external engine compartment mounted reservoir for conditioning and storage. Oil is transported to the top of the tank through an internal scavenge return tube, where it is tangentially spilled out on a spiral-shaped internal baffle. When the aerated oil from the engine contacts the internal surfaces of the tank, crankcase gasses and air which are entrained in the oil are separated out. These gasses are directed by the PCV system through a series of baffles and tubes back to the crankcase and into the combustion chamber to be burned. The de-aerated oil is directed down the walls of the tank to collect in the 10 quart reservoir, conditioned and ready for use. The second stage of the dual stage gerotor pump then draws the conditioned oil from the tank and pressurizes it, feeding it to the engine via the oil filter and oil cooler. The routing of the engine oil to and from the dry sump reservoir also provides the benefit of passive oil cooling.

If its capability and high-speed potential seem to suggest otherwise, the LS7 nonetheless requires minimal maintenance. Its advanced iridium-core spark plugs and Dexcool coolant are validated to 100,000 miles of operation, with the same level of performance at 90,000 miles as they deliver at 10,0000. The LS7 also features an oil-level sensor and GM's advanced Oil Life System. This technology measures stress on the engine and calculates oil life based on real-world use rather than a predetermined mileage interval. It eliminates unnecessary oil changes in vehicles that are driven in light duty conditions.

For all the improvements and advanced technologies built into the 7.0L LS7 V8, the bottom line still counts most. This is an ultra-high performance engine, with capabilities suited to one of the best performing sports cars in the world. It takes a back seat to no V8, blurring the line between overhead-cam and pushrod-actuated technology to the point where the distinction is meaningless-except for the relative cost advantages the pushrod engine delivers to both corporation and customer.