GM 6.2 Liter V8 Vortec L94 Engine

The L94 is one of the most technically advanced truck engines in the segment, with features that include variable valve timing, Active Fuel Management cylinder-deactivating technology and E85 flex-fuel capability. The 6.2L is the most powerful of GM’s Vortec V8s. It delivers exceptional refinement to go with brute strength, and advanced technologies such as cam-in-block variable valve timing. It was also developed for quieter operation, with virtually every system or component reviewed in an effort to reduce noise, vibration and harshness. Quiet features built into the engine are complemented by an improved engine cradle and mounting system. These help reduce vibrations transmitted through the chassis and into the passenger compartment.

Engine highlights:

• Gen IV Cylinder Block and Rotating Assembly: the engine 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. Along with the rigid block, the engine’s rotating assembly was designed for optimal strength and duration complemented by features designed to make the L94 quiet and smooth. The L94 6.2L also features a heavy-duty timing chain developed expressly for quiet operation. The chain, which connects the camshaft and crankshaft, is validated for 200,000 miles of operation and fitted with a leaf-spring-type dampener.
• High-Flow Cylinder Heads and Valvetrain: the L94’s cylinder heads feature rectangular intake ports that support exceptional airflow. 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 6.2L features variable valve timing, maximizing engine performance for given demands and conditions. At idle, for example, the cam is at the full advanced position, allowing exceptionally smooth idling. Under other conditions, the phaser adjusts to deliver optimal valve timing for performance, drivability and fuel economy. At high rpm’s it may retard timing to maximize airflow through the engine and increase horsepower. At low rpm’s it can advance timing to increase torque. Under light loads, it can retard timing at all engine speeds to improve fuel economy.
• E85 Flex Fuel Capability: E85 is a clean-burning, domestically produced fuel, composed of 85 percent ethanol alcohol and 15 percent gasoline. Ethanol is renewable, and produces fewer greenhouse gases during the combustion process. It can be produced from various feed stocks, including corn and wheat stalks, forestry and agricultural waste and even municipal waste.
• Active Fuel Management: GM’s Active Fuel Management technology increases fuel economy approximately 6 percent under the federal government’s required testing procedure and potentially more in certain real-world driving conditions. AFM temporarily deactivates four of the L94’s cylinders under light load conditions and seamlessly reactivates them when the driver demands full power. The transition takes less than 20 milliseconds, and is virtually indiscernible to most drivers.
• High-flow Intake Manifold with Acoustic Shell: the L94’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.
• 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.
• Quiet Exhaust Manifolds: the exhaust manifolds were developed to improve durability and sealing and reduce operational noise. Cast nodular iron was the material of choice for its basic durability and excellent heat-management properties. The manifolds are fitted with new triple-layer heat shields fabricated from stainless steel and insulating material. The shields limit heat transfer from the engine to the engine bay, allowing the 6.2L to reach optimal operating temperature more quickly, yet reducing heat in the engine compartment once that temperature is achieved.
• 58X Ignition System: the L94 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.