GM 6.0 Liter V8 Small Block LS2 Engine
The 6.0 liter V8 LS2 engine was produced by General Motors for use in performance vehicles and sports cars. It is part of GM’s Gen IV Small Block engine family and was first introduced in the 2005 Chevrolet Corvette C6, Chevrolet SSR and the Pontiac GTO.
|Displacement:||6.0L / 364 cu. in.|
|Vehicles:||Corvette C5, Chevrolet SSR, Chevrolet Trailblazer SS, Cadillac CTS-V, Pontiac GTO, Saab 9-7X Aero|
|Introduced:||2005 model year|
|Predecessor:||LS1 / Gen 3 Small Block|
|Assembly:||Saint Catherines, Ontario, Canada|
A completely different engine with the LS2 RPO Code was used by Pontiac between 1973 and 1974. That engine displaced 7.5 liters (455 cubic-inches) and featured an engine design that was bespoke to Pontiac, and is therefore not related to this fourth-gen LS2.
The 6.0L LS2 engine debuted in the 2005 Chevrolet Corvette C6, and was also immediately placed into several other General Motors products for the 2005 model year. Unlike the LS1 engine upon which it is based, the LS2 is classified as the starting point for the newer Gen IV small block family, though, the Gen III and Gen IV engines share many similarities, and have many interchangeable parts. The Gen IV small block uses the same cam-in-block architecture and 4.400-inch bore centers (the distance between the centers of each cylinder) that are design features shared with the very first small block upon its launch in 1955.
The Gen IV engine, despite its similarities with the Gen III engines, did showcase several new design cues and technologies. The most prominent of which is the inclusion of General Motors’ Active Fuel Management system, which was sometimes referred to as “Displacement on Demand.” LS2 engines with this system were designated RPO code L76.
Further refinements to the LS2 engine over the LS1, as well as the slight bump in displacement offered a notable increase in power, with the Corvette C6 debuting with 400 horsepower and 400 pound-feet of torque.
Engine highlights include:
- Cylinder block: the LS2 cylinder block shares two key design elements with GM’s original small-block V8: a 90-degree cylinder angle and 4.400-inch bore centers. The bore and stroke dimensions are: 4.00-inch (101.6 mm) bore x 3.62-inch (92 mm) stroke, which gives the LS2 a 0.3L increase in displacement.
Compared to the Gen III small block LS1, the LS2’s aluminum cylinder block casting is all-new, but based on the same basic principle, again, many parts can be used interchangeably. However, of note is that certain sensors, like the cam position sensor and knock sensors have been relocated.
- Oiling System: the oiling system is a lightly-tweaked version of what was seen in the Gen III engines. The oil pump is still driven by the crankshaft. However, the addition of active fuel management required a redesign of the oil galleries to maintain adequate oil pressure throughout the engine as various cylinders were deactivated and reactivated in use.
The Corvette C6, in particular, received a redesigned baffled oil pan to ensure a constant supply of oil to the oil pick-up in the sump during high G-force cornering and track day driving. This reduced the oil capacity of the C6’s LS2 engine to 5.5L.
- Rotating assembly and windage tray: within the Gen IV block is a durable rotating assembly that includes a steel crankshaft and 6.098-inch-long, powder-metal connecting rods, as well as hypereutectic cast aluminum-alloy pistons. The pistons have a flat top design, and the piston rings have been redesigned to have less friction.
The crankshaft in the Gen IV small block is located with grey iron main caps, comparable to what was found in the Gen III engines.
- PCV System: the positive crankcase ventilation system design of the LS2 was lifted from the LS6 engine, which itself, was redesigned from the LS1. Instead of pulling crankcase gases and engine oil blow-by from the valve cover, the system, instead, had its pickup in the valley cover, in between the cylinder banks, beneath the intake manifold. This designed system is better able to capture built up crankcase gases, rather than capture excess oil moving around the valvetrain, reducing possible oil consumption issues noted on early LS1 engines.
- Camshaft Design: also rotating inside the engine block is a hydraulic roller-lifter camshaft, however, while the LS2 pulls many design cues from the LS6 before, the LS2 features a notably less aggressive cam profile, with less lift and duration, with comparable LSA.
The LS2 camshaft’s specifications lift include: 0.520/0.521-intake/exhaust lift, 204/213-crank angle degrees intake/exhaust duration at 0.050 tappet lift and 116-degree cam angle lobe separation.
- Cylinder Head Design: the LS2 cylinder heads are almost identical to what was used on the LS6 engine, right down the “243” stamp in the castings. Both have the same 65cc combustion chambers and Cathedral intake ports. Though, the LS2 gets a further compression ratio bump, now up to 10.9:1
- Steel intake and exhaust valves are used in the aluminum alloy heads, and they measure 2.00-inch (50.8mm) intake and 1.575-inch (40.5mm) in diameter. Unfortunately, they are not sodium-filled like the LS6. The valves are held at 15 degrees intake/15 degrees exhaust angles.
- Valvetrain components include beehive valve springs and roller-pivot rocker arms with a 1.7 ratio – the amount of movement on the valve side of the rocker arm in comparison with the pushrod side.
- Pushrod design is common to the Gen III engine, and they measure 7.385-inches long.
- Fuel Injection System: sequential port-fuel injection is utilized on all Gen IV engines. Port-fuel injection places the injectors on a fuel rail mounted the intake manifold. From there, the injectors spray fuel into the intake ports, just ahead of the combustion chamber. The fuel then mixes with incoming air before going through the combustion cycle. LS2 injectors are rated at 34 lb/hr, which means they have more performance head room than the lower-flowing injectors used in the Gen III engines.
- The LS2 utilizes a conventional in-tank fuel pump, with an in-line fuel filter.
- Active Fuel Management: Active Fuel Management temporarily deactivates four of the cylinders and seamlessly reactivates them when the driver demands full power. When cylinders are deactivated, the engine’s pumping work is reduced, which translates into real-world fuel economy improvements.
The key to AFM’s efficiency and seamless operation is a set of two-stage hydraulic valve lifters, which allows the lifters of deactivated cylinders to operate without actuating the valves. In engineering terms, this allows the working cylinders to achieve better thermal, volumetric and mechanical efficiency and lowering cyclical combustion variation from cylinder to cylinder. As a result, AFM delivers better fuel economy and lower operating costs. The only mechanical components required are special valve lifters for cylinders that are deactivated, and their control system. Active Fuel Management relies on three primary components: Collapsible or “de-ac” (deactivation) valve lifters, a Lifter Oil Manifold Assembly (LOMA) and the engine controller, which determines when to deactivate cylinders.
- Exhaust Manifolds: the LS2 manifolds weigh 1/3rd less than the Gen III manifolds, a function of reduced wall thickness, from 4mm to 3mm. GM claims they also offer a four percent improvement in flow.
- Intake Manifold and Electronic Throttle: all Gen IV engines now feature electronic throttle control, which allows for the deletion of an idle-air control motor. The throttle body into the intake manifold now measures 90mm (3.55-inches). The manifold design itself is a general revision of the LS6 intake and is still made of composite plastics.
- Cooling System: the Gen IV cooling system sees just a light tweak compared to the Gen III engines with a redesigned water pump that is both lighter than the Gen III setup as well as less likely to leak with age, a somewhat common issue with Gen III blocks.
- Ignition System: the Gen IV has a more efficient coil-near-plug ignition system with redesigned coil packs.
- Curiously, early LS2 engines, from 2005 to mid-2006 featured the same 24-tooth reluctor wheel setup used on the Gen III engines. However, GM redesigned the system, upgrading to the more modern 58-tooth setup, which provided more accurate crank position data to the ECU. This system would go on to be standard equipment on all LS-based small block engines going forward.
- E38 Engine Controller: operation and performance of the Gen IV is overseen by several different ECMs depending on the model year and crank reluctor wheel setup on the engine. Most LS2 engines use an engine controller marked as E38 or E40.
|Type:||6.0L Gen IV V8 Small Block|
|Displacement:||6.0L (5965cc / 364 ci)|
|Valve configuration:||Overhead valves|
|Valves per cylinder:||2|
|Assembly site:||Saint Catherines, Ontario, Canada|
|Valve lifters:||Hydraulic roller|
|Firing order:||1 – 8 – 7 – 2 – 6 – 5 – 4 – 3|
|Bore x stroke:||101.6 x 92mm|
|Fuel system:||Sequential Port Fuel Injection|
|Fuel type:||Premium Recommended|
|Maximum Engine Speed:||6500 RPM|
|Cylinder head:||Cast aluminum|
|Exhaust manifold:||Cast Iron|
|Main bearing caps:||Cast Iron|
|Connecting rods:||Forged Powder Metal|
|Active Fuel Management|
|Electronic throttle control|
|Oil Life Monitor System|
|58x crank timing|
|Positive crankcase ventilation|
|Vehicle||Transmission||Power (hp / kW @ RPM)||Torque (lb-ft / Nm @ RPM)|
|2005-2007 Chevrolet C6 Corvette (Coupe / Convertible)||4L65E (4-speed auto) / 6L80 (6-speed automatic) / T-56 (6-speed manual)||400 / 298 kW @ 6000||400 / 542 @ 4400|
|2005-2006 Chevrolet SSR||4L65E (4-speed auto) / T-56 (6-speed manual)||390-400 / 291-298 kW @ 6000||400 / 542 Nm @ 4400|
|2005-2006 Pontiac GTO||4L60E (4-speed auto) / T-56 (6-speed manual)||400 / 298 kW @ 6000||400 / 542 Nm @ 4400|
|2006-2009 Chevrolet TrailBlazer SS||4L70E (4-speed auto)||390 / 291 kW @ 6000||400 / 542 Nm @ 4400|
|2006-2007 Cadillac CTS-V||T-56 (6-speed manual)||400 / 298 kW @ 6000||400 / 542 Nm @ 4400|
|2008-2009 Saab 9-7X Aero||4L70E (4-speed auto)||390 / 291 kW @ 6000||400 / 542 Nm @ 4400|
Follow our coverage of GM LS2 engine news.
Other members of the Gen IV Small Block engine family include:
- Naturally-aspirated 6.0L V8 L76
- Naturally-aspirated 6.0L V8 L77
- Naturally-aspirated 6.0L V8 L98
- Naturally-aspirated 5.3L V8 LS4
- Naturally-aspirated 7.0L V8 LS7
- Naturally-aspirated 6.2L V8 LS3
- Naturally-aspirated 6.2L V8 L99
- Supercharged 6.2L V8 LS9
- Supercharged 6.2L V8 LSA
Gen IV Vortec motors for pickup trucks, consisted of the following engines: