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GM 2.7L L3B Inline-4 Turbo Engine (Design, Problems & Reliability)

The GM L3B is a 2.7 litre turbocharged four-cylinder engine, it's developed by General Motors for use in a variety of vehicles, with a focus on full-size pickup trucks and larger cars. The L3B engine made its debut with an SAE-certified output of 310 horsepower and 348 pound-feet of torque.


Since then, the engine has undergone several updates, including a high-output version that boasts even higher levels of torque, making it a powerful and efficient option for truck applications.


In this article, we will discuss the design and specs of the GM 2.7L L3B Inline-4 turbo engine as well as its reliability and tuning options.


Table of Contents:


GM 2.7L L3B Inline-4 turbo engine

L3B Engine Design

The GM L3B engine is a 2.7 litre turbocharged four-cylinder engine; it is a clean-sheet design developed by General Motors for use in various vehicles, focusing on full-size pickup trucks and cars.


This engine was specifically designed to meet the demands of truck applications and was first introduced in the 2019 Chevrolet Silverado 1500 and 2019 GMC Sierra 1500.


The L3B engine has a displacement of 2.7 litres and is configured in an inline-four cylinder configuration. The engine was developed from the outset as a truck engine to generate the strong low-end torque that customers expect in a truck.


The engine was designed to achieve a strong torque output with a long piston stroke of 4.01 inches (102mm); the piston stroke is the distance the piston travels up and down within the cylinder.


The long piston stroke enables improved combustion, resulting in a higher compression ratio and allowing the engine to produce more power while consuming less fuel.


The engine also features a unique offset crankshaft design, which allows for a more upright position for the connecting rods during their movement. This helps to alleviate the load of the pistons against the cylinder walls, reducing friction and improving efficiency.


The crankshaft and connecting rods are made of forged steel, a strong and durable material that can withstand high loads and stresses to support the high cylinder pressures that come with turbocharging.


  • The pistons are made of a tough aluminium alloy with a cast-iron ring groove insert, which allows for improved heat dissipation and increased durability.

  • The GM L3B engine also features an aluminium block and cylinder head for reduced mass, which helps to improve fuel efficiency and performance.


The GM 2.7L L3B engine is a powerful and efficient option for truck applications, specifically designed to meet the demands of truck applications, with advanced features such as the following.


  • A long piston stroke of 4.01 inches (102mm)

  • Offset crankshaft design

  • High-strength components (forged steel con-rods and crankshaft)

  • Reduced mass (aluminium block and head)


With the introduction of the 2022 Chevrolet Silverado, General Motors made significant changes to the L3B engine design to improve its performance and durability. These changes resulted in an increased torque rating of 420 lb-ft and also reduced noise, vibration, and harshness (NVH).


GM 2.7L Turbo Engine Specs

Manufacturer

General Motors (GM)

GM RPO Code

L3B

Production

2018+

Configuration

Inline four cylinder

Displacement

2.7 litres (2,727 cc)

Cylinder Bore

​92.25 mm (3.63 in)

Piston Stroke

102 mm (4.02 in)

Valvetrain

DOHC, 4 valves per cylinder with VVT (variable valve timing) and VVL (variable valve lift)

Compression Ratio

10.0:1

Firing Order

1-3-4-2

Redline

6100 RPM