The 6.0-liter L99 V8 engine is an engine was produced by General Motors for use in high-performance vehicles. Part of GM’s 4th-generation V8 Small Block engine family, the engine has a displacement of 6.2 liters and features eight cylinders in a “V” layout. The L99 is a variant of the popular LS3 V8 but is FlexFuel capable and features Active Fuel Management (cylinder deactivation), while the LS3 doesn’t have either of those features.
The L99 is assembled at GM’s facilities in St. Catharines, Ontario and is utilized by fifth-generation Chevrolet Camaro SS models and Chevrolet SS sedans equipped with automatic transmissions. Meanwhile, such models equipped with the six-speed manual transmission are powered by the LS3. Notably, Chevrolet Performance still manufacturers the the LS3 as a crate engine offering.
The L99 6.2L V8 offers Active Fuel Management (AFM) cylinder deactivation technology and FlexFuel capability, allowing it to run on E85 ethanol. Active Fuel Management allows the engine to operate on only four cylinders during certain light-load driving conditions, saving the fuel normally used to drive all eight cylinders. 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 L99 offer camshaft phasing, while its efficiency also optimizes emissions performance.
Engine highlights:
- Cylinder Block: the L99 6.2L’s cylinder 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.
- High-Flow Cylinder Heads and Valvetrain: the L99’s cylinder heads feature rectangular intake ports that support exceptional airflow. They support great airflow at higher rpm for a broader horsepower band, along with strong, low-rpm torque. The intake ports that feed the combustion chambers, as well as the D-shaped exhaust ports, are designed for excellent high-rpm airflow.
- Camshaft Phasing: the L99’s valvetrain interfaces with a camshaft phaser to provide 30 degrees of phasing authority. This means the engine delivers variable valve timing to optimize performance and efficiency.
- High-flow Intake Manifold With Acoustic Shell: the L99’s intake manifold ports are designed to match the 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.
- Advanced Electronic Throttle Control: 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. The ETC system can deliver outstanding throttle response and greater reliability than a mechanical connection.
- Active Fuel Management: AFM temporarily deactivates four of the L99’s cylinders under light load conditions and seamlessly reactivates them when the driver demands full power. AFM is managed by the engine control module (ECM). When conditions are optimal, it automatically shuts down every second cylinder, according to firing order, during light-load operation. As a result, AFM delivers better fuel economy and lower operating costs.
- 58X Ignition System: the L99 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.
| Type: | 6.2L Gen IV V8 Small Block |
| Displacement: | 6162cc (376 ci) |
| Engine Orientation: | Longitudinal, |
| Compression ratio: | 10.4:1 |
| Valve configuration: | Overhead valves |
| Valves per cylinder | 2 |
| Assembly site: | St Catharines, Ontario, Canada |
| Valve lifters: | Hydraulic roller |
| Firing order: | 1 – 8 – 7 – 2 – 6 – 5 – 4 – 3 |
| Bore x stroke: | 103.25 x 92 mm |
| Bore Center (mm) | 111.76 |
| Bore Area: (cm2) (total engine bore area) | 669.82 |
| Fuel system: | Sequential fuel injection |
| Fuel Type: | Premium fuel recommended, not required |
| Maximum Engine Speed: | 6200 RPM |
| Engine Redline: | 6000 RPM |
| Engine Mass: | TBD |
| Materials | |
| Block: | Cast aluminum |
| Cylinder head: | Cast aluminum |
| Intake manifold: | Composite |
| Exhaust manifold: | Cast nodular iron |
| Main bearing caps: | Powder metal |
| Crankshaft: | Cast nodular iron with undercut and rolled fillets |
| Camshaft: | Hollow steel |
| Connecting rods: | Forged powder metal |
| Additional Features | |
| Variable Valve Timing (VVT) | |
| Active Fuel Management | |
| Electronic throttle control | |
| Extended life accessory drive belt | |
| Extended life coolant | |
| Extended life spark plugs | |
| Oil Life Monitor System | |
| Emissions Controls | |
| Catalytic converter | |
| Three-way catalyst | |
| Positive crankcase ventilation | |
| Year | Make | Model | Transmission | Power (hp / kW @ RPM) | Torque (lb-ft / Nm @ RPM) |
|---|---|---|---|---|---|
| 2009-2015 | Chevrolet | Camaro SS Coupe and Convertible | 6-Speed Auto | 426 / 318 @ 5900 | 420 / 569 @ 4600 |
| 2015-2017 | Chevrolet | SS | 6-Speed Auto (6L80) | 415 / 310 @ 5900 | 415 / 563 @ 4600 |
Follow our coverage of GM L99 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
- Supercharged 6.2L V8 LS9
- Supercharged 6.2L V8 LSA
Gen IV Vortec motors for pickup trucks, consisted of the following engines:
- 6.0L V8 LY6
- 6.0L V8 L96
- 6.0L V8 LFA
- 6.0L V8 LZ1
- 4.8L V8 LY2
- 4.8L V8 L20
- 5.3L V8 LMF
- 5.3L V8 LH6
- 5.3L V8 LC9
- 5.3L V8 LY5
- 5.3L V8 LMG
- 5.3L V8 LH8
- 5.3L V8 LH9
- 6.2L V8 L92
