A listing of new and updated features of the 2008 Corvette LS3 engine from GM Powertrain.
Source: GM Powertrain
6.2L V8 (LS3) CAR ENGINE
Description of New and Updated Features
Overview
For 2008, General Motors Powertrain engineers have again added a performance kick to the Corvette base engine with introduction of the new LS3 6.2L engine which replaces the LS2. The 2008 6.2L LS3 V8 with 430 Hp @ 5900 rpm and 424 lb.ft. torque @ 4600 rpm is the most powerful Corvette base engine ever and is SAE Certified for 2008 model year.
The LS3 engineering team focused on design elements to increase flow efficiency in addition to the displacement increase to meet the performance enhancement. The bore was increased to a larger 103.25 mm diameter compared to the LS2 bore of 101.6. Engine stroke remains at 92.0mm. Intake flow efficiency was optimized by straightening out and optimizing the flow path from the intake manifold into the cylinder heads. A high flow efficiency induction system is borrowed from the Z06 application. The cylinder head exhaust ports have been modified to increase flow. Also now available in the Corvette with the LS3 is a butterfly valve in the exhaust system which 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 LS3 to hum at a more muted burble during part-throttle operation. The LS3 also meets the more stringent Bin4 emission standards and again avoids the gas guzzler tax. The small block tradition of more for less continues.
High Flow Cylinder Heads
The intake port shape size and shape have been modified to increase flow. The higher flow intake ports are similar to the L92 6.2L. Casting changes were made to increase the opening at the exhaust face to improve exhaust port flow. A new exhaust manifold opening is required to match the heads.
Enhanced valvetrain
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 increased from 50.8 to 55.0 mm. Hollow stem intake were implemented to enable the 6600 rpm capability (13% reduction in mass from LS2). The 40.4 mm diameter exhaust valves are carried over from L92. Carryover LS2 high load valve springs are also included for 6600 rpm capability. Intake lift increases from 13.25mm to 14.0mm. Exhaust lobes are carryover LS2. Camshaft timing is revised.
Higher flow intake manifold with acoustic shell
Intake ports revised to match new cylinder head. The new composite intake 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.
Larger bore block with structural improvements
Casting and machining in the bulkheads was revised to improve block structure and to improve bay to bay breathing. The enhanced cylinder block is shared with the the 6.2L truck applications.
New Pistons
A new larger diameter piston design is introduced for which includes design enhancements for the higher engine output.
Higher Flow Injectors
Higher flow 5.0 g/s injectors were used from the LS7 engine.
New Acoustic / Beauty Cover
The new beauty cover has a revised appearance and new acoustic treatment.