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LS3 engine specifications
The LS3 was introduced as the Corvette's new base engine for the 2008 model year. The block is an updated version of the LS2 casting featuring a larger bore of 4.06 in (103 mm) creating a displacement of 6.2 L (6,162 cc/376.0 cu in). It also features higher flowing cylinder heads sourced from the L92, a more aggressive camshaft with 0.551" lift, a revised valvetrain with 6 mm (0.24 in) offset intake rocker arms, a high-flow intake manifold and 47 lb/hr fuel injectors from the LS7 engine.
The L76/L92/LS3 cylinder heads use 2.165 in (55.0 mm) intake valves, and 1.59 in (40 mm) exhaust valves. For use with 4 in (100 mm) and larger bores, they allow for over 600 hp (450 kW) naturally aspirated. Improved manufacturing efficiency makes these heads cheaper than the outgoing LS6 heads, and severely undercuts aftermarket heads. The large valves, however, limit maximum rpm - 6000 in the L76 (with AFM), and 6600 in the LS3 (with hollow stem valves).
In addition to the above, a dual mode exhaust package with a bypass on acceleration is available. The dual-mode exhaust uses vacuum-actuated outlet valves, which control engine noise during low-load operation, but open for maximum performance during high-load operation. The system is similar to the C6 Z06, but uses a 2.5 in (64 mm) diameter exhaust compared to the Z06's 3 in (76 mm). Power is boosted to 436 hp (325 kW) and 428 ft·lbf (580 N·m) with this option. See chart below for LS3 application on the 2010 Camaro.
Info from GM:
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.
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.
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.
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