GM 2.7 L3B Turbo: Everything You Need To Know

The recent release of the GM L3B engine aimed to replace the 4.3L V6 engine and make it out successfully. The engine was far better in different categories, including a larger power output by nine percent, fourteen percent more torque, consuming thirteen percent less fuel, and lighter by 80 lbs. 

On top of that, even though it is designed as a truck engine, the GM 2.7 L3B Turbo has fewer emissions than its predecessor. But, where does the GM 2.7 L3B Turbo place amongst its competitors? 

What are GM 2.7 L3B Turbo Engines?

The GM 2.7 L3B Turbo engine is a new turbocharged engine introduced by General Motors in different vehicles, including cars and full-size pick-up trucks. Some of the common applications of the engine include the MY 2019 Chevrolet Silverado and the 2020 – 2021 Cadillac CT 4-V. 

The G 2.7 L3B engine displaces 2.7 Liters in an inline-four configuration designed originally as a truck engine. With its architecture, the intention is evident; it is meant for heavy-duty applications in a smaller package.

The engine features a lot of modern-era technologies since it was made less than five years ago. 

Adopting prior technologies like active fuel management or cylinder deactivation, variable valve timing, and a start-stop system.

The GM 2.7 L3B engine has an electronically activated Intake Valve Lift Control with three different intake cam profiles to provide excellent fuel economy and performance at a wider range of load conditions. 

It is also the first GM engine to have a thermal management system. This system allows the engine to maintain operating temperature and faster warm-ups through an electrically-driven water pump and a three-way rotary valve.

Further, GM added a continuously variable oil pump to dampen parasitic losses and provide better lubrication and cooling to the engine, especially during high-load situations. 

As we mentioned earlier, the GM 2.7 L3B engine is a turbocharged one. So, it does come with a turbo. Borgwarner developed a turbo for this engine capable of producing 22 psi of boost.

The characteristics of the turbo helped with its unique volute turbine housing and electrically-actuated wastegate. 

Unlike the side-by-side exhaust passage of twin scrolls, BorgWarner designed the two exhaust passages concentric, allowing better utilization of the exhaust pulse energy. 

Engine Specifications and Design:

  • Production Run: 2018 – Present
  • Cylinder Head Material: Aluminum
  • Cylinder Block Material: Aluminum
  • Configuration: Inline-4
  • Bore: 92.25 mm
  • Stroke: 102.0 mm
  • Valvetrain: DOHC with four valves per cylinder with VVT and VVL
  • Displacement: 2.7 L (2727 cc)
  • Compression Ratio: 10.0
  • Weight: 250 lbs. 
  • Maximum HP: 325 HP at 5,600 RPM
  • Maximum Torque: 380 lb-ft at 4,000 RPM

Engine Design

Let’s take a look inside the engine!

Cylinder Block

The GM 2.7 L3B turbo has a deep-skirt die-cast aluminum cylinder block with cast-iron liners. It has a long piston stroke of 102 mm, providing a strong low-end torque, but this increases unnecessary vibrations on the downside.

To balance the compromise, GM placed a dual balance shaft mechanism in the engine block. 

The engine has a forged steel crankshaft with tri-metal bearings and hardened journals. Though it is uncommon, the crankshaft offset the cylinder bore centerline reducing the friction from piston side-loading. 

The pistons are lightweight aluminum with cast-iron ring carriers and a fully machined crown which are cooled by oil spray squirters. The engine is equipped with a continuously variable-output oil pump supported by a blot-on aluminum lower crankcase extension, together with the balance shafts.

A nylon-reinforced plastic oil pan seals the bottom side of the block. 

Cylinder Head

Placed on top of the engine block is an aluminum 16-valve cylinder head with high-tumble combustion chambers and dual-overhead camshafts. GM used copper-alloy exhaust valve guides for their cylinder to improve heat transfer and valve cooling. An 8-mm roller timing chain drives the intake and exhaust camshafts. 

Furthermore, the GM 2.7 L3B valvetrain features a Sliding Cam Valve Lift System or SCS with three operating modes – Low Lift, High Lift, and Active Fuel Management mode.

In low lift mode, this reduces the intake valve opening duration to save fuel under medium load conditions. In high lift mode, all cylinders are active, and all valves open at their peak extension. 

However, in AFM or Active Fuel Management mode, cylinders 2 and 3 are deactivated, reducing fuel consumption in light load conditions. Further, the intake and exhaust sides come with continuously variable valve timing management. 

Direct-Injection 

The GM 2.7 L3B turbo operates and features a high-pressure direct fuel injection system. The pump can deliver 3000 psi of fuel pressure for side-mounted direct-injectors, delivering three events per combustion cycle.

The direct injection seamlessly applies the Spark Ignited Direct Injection with the high-energy coil-on-plug electronically controlled ignition system. 

Since this is a new turbocharged engine, the GM 2.7 L3B employs a cylinder head design with an integrated and water-cooled exhaust manifold to expedite engine warm-ups, prolonging the turbocharger longevity keeping it cool during high demand loads. 

The new feature of the engine is GM’s active thermal management cooling system. This system cools the engine and transmission through an electric water pump that supplies coolant flow to heat the passenger compartment. 

Additional Engine Features

Variable-Pressure Oiling System

A variable pressure oiling system equipped with a continuously variable displacement vane oil pump improves efficiency by optimizing oil pressure as a function of load and engine speed.

In this way, the oil supply is matched to the engine requirements rather than the extravagant supply of a conventional, fixed-displacement oil pump. 

Stop/Start Technology

This technology automatically stops the engine in stop-and-go traffic for better fuel efficiency and improves fuel economy in most congested areas. The selection system shuts off the engine at stoplights and other stop-and-go situations, saving more fuel.

The engine automatically restarts when the driver takes the brake off. 

2020 Model Year Update

The upcoming Silverado will feature the newly-updated GM L3B Turbo engine. GM announced significant changes that the engine underwent, including the stiffening and strengthening of the engine, allowing an increase in torque rating up to 420 lb-ft at 3,000 RPM.

Applications of GM 2.7 L3B Turbo Engine: 

  • 2019 – 2020 Chevrolet Silverado 1500 310 HP and 348 lb-ft 
  • 2019 – 2020 GMC Sierra 1500 310 HP and 348 lb-ft 
  • 2022 Chevrolet Silverado 1500 310 HP and 420 lb-ft 
  • 2022 GMC Sierra 1500 310 HP and 420 lb-ft 
  • 2020 – Present Cadillac CT4-V Premium Luxury 325 HP and 380 lb-ft 
  • 2023 Chevrolet Colorado 310 HP and 340 lb-ft 
  • 2023 GMC Canyon 310 HP and 340 lb-ft 

Problems Surrounding GM 2.7 L3B Engine

The GM 2.7 L3B turbo engine is still young, so there are still issues that cannot be determined as of now. It is not yet a decade-long engine too. But, we hope that this engine will build a reputation based on its expectations laid out by the enthusiasts.

But based on the current standing of the engine, it is pretty reliable and can last for years to come. We should give thanks to the technologies and engineers who crafted this engine.

It is a truck-designed truck so expect that this will last for a long time, but take note that truck engines have issues with emissions. 

But, let’s not be ahead of ourselves and the pack. We can conclude that the engine is packed with excellent technology to be a top-notch engine with a great build for fuel efficiency and performance.

GM claimed that this engine successfully accumulated approximately one million miles of over the road validation testing. Only the owners and potential owners can tell. 

But, for now, let us take the common advice from the rulebook, always use the recommended engine oil. Since this is a new engine, it is more sensitive to the quality and condition of the oil, like most modern turbocharged and direct-injection engines. 

Improper or lack of maintenance will juice the life of this engine.

There is also a contention regarding GM’s decision to use direct injection only, while other engines combined port and direct injection. Combined fuel injection extends the life of the cylinder wall surface and prevents carbon build-up on the intake valves and cylinder walls inside the ports. 

Summary 

The GM 2.7 L3B Turbo engine has not been for more than a decade, but the elements and technologies integrated are already top-notch. We will need to wait for the engine to come out with its true potential before determining its rank among the modern engine in this era. 

It has already shown itself, though not the whole, but it is highly anticipated on the upcoming release of the engine. 

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