Vehicle Applications

2011 6.2L V-8 (LS3)

Vehicle Applications Chevrolet Camaro SS (with manual transmission) Chevrolet Corvette / Corvette Grand Sport

Product Highlights  Gen IV aluminum cylinder block  High-flow L92-style aluminum cylinder heads  High-flow intake manifold with acoustic shell  Dry sump-style oiling system for Corvette Grand Sport with manual transmission  Advanced electronic throttle control  58X ignition system  426 horsepower (318 kW) at 5,900 rpm (Camaro SS)  430 horsepower (321 kW) at 5,900 rpm (Corvette/Corvette Grand Sport)  420 lb.-ft. of torque (569 Nm) at 4,600 rpm (Camaro SS)  424 lb.-ft. of torque (575 Nm) at 4,600 rpm (Corvette/Corvette Grand Sport)

Overview GM’s Gen IV engine family is a great example of the enduring power of the overhead-valve small-block V-8 architecture that Chevrolet introduced in 1955. Compared to many overhead- cam V-8 engines, the Gen IV family offers compact dimensions that enable it to fit under the low hoodline of sporty cars, such as the Chevrolet Corvette, as well as the deep well of torque that is an inherent trait of overhead-valve engines.

The 6.2L LS3 is a direct descendant of the original small-block, sharing key dimensions including 4.40-inch bore centers (the width between the centers of the cylinders). Engineers have used the latest technology to make the LS3 not only powerful, but surprisingly efficient. It is the standard engine in the Chevrolet Camaro SS (with a manual transmission), where it delivers 426 horsepower (318 kW) and EPA-estimated highway mileage of 24 mpg. It is also standard in the Corvette and Corvette Grand Sport, where a different exhaust configuration enables the engine to produce 430 horsepower (321 kW). Highway mileage for the lightweight Corvette models is 25 mpg. As with other members of the Gen IV engine family, one of the enablers of the LS3’s balance of performance and 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 provides an optimum reduction in emissions.

Apart from exhaust and accessory drive variances, the LS3 engines in the Camaro SS and Corvettes models are identical, although Corvette Grand Sport models equipped with the TR6060 six-speed manual transmission feature a dry sump-style oiling system to ensure adequate oiling during high-load cornering.

Gen-IV Cylinder Block and Rotating Assembly 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. The bores themselves are 4.006 inches (103.25 mm) in diameter and matched by a 3.620-inch (92 mm) stroke.

The Gen IV block was developed with 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.

Within the LS3 block is a durable rotating assembly that includes a steel crankshaft and connecting rods, as well as high-strength, aluminum-alloy pistons. The flat-top pistons are also lightweight, which enhances high-rpm performance, as they enable the engine to rev quicker. Also rotating inside the engine block is a camshaft with 0.551-inch (14 mm) lift on the intake side and 0.522-inch (13.2 mm) lift on the exhaust side.

High-Flow Cylinder Heads and Valvetrain The LS3’s cylinder heads feature rectangular intake ports that support exceptional airflow. They’re based on the design of the high-performance L92 cylinder heads, which is used on vehicles including the Cadillac CTS-V and Chevrolet Corvette ZR1. They support great airflow at higher rpm for a broader horsepower band, along with strong, low-rpm torque. Large, 2.165-inch hollow-stem intake and 1.590-inch solid-stem exhaust valves are used in the 356-T6 aluminum alloy heads. The lightweight hollow-stem intake valves enable the engine to rev quickly and capably to greater than 6,000 rpm.

The intake ports that feed the combustion chambers, as well as the D-shaped exhaust ports, are designed for excellent high-rpm airflow. The intake 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 the exhaust valve diameter is 40.4 mm. Valve lift is 0.500-inch (12.7mm) on the intake and exhaust sides.

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.

Dry Sump-Style Oiling System for Corvette Grand Sport with Manual Transmission Corvette Grand Sport models equipped with the manual transmission feature a dry sump-style oiling system and dual-gerotor oil pump to promote durability during extended high-rpm use under high cornering loads. 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 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 that 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 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.

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.

Returnless Fuel Injection The LS3 is equipped with a “returnless'” fuel injection system, also known as a demand system, that helps optimize performance and emissions. It delivers only the amount of fuel needed by the injectors, and returns no fuel to the gas tank, which essentially eliminates heat transfer from the engine to tank. This reduces the amount of vapor generated in the tank and captured by the vehicle's Onboard Refueling Vapor Recovery (ORVR) system.

58X Ignition System The LS3 has an advanced 58X crankshaft position encoder to ensure that ignition timing is accurate throughout its operating range. The 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 backup system in the event one sensor fails.