Chevrolet LGX Specifications
| Engine Model: Chevrolet LGX |
| Engine Type: 4-cycle 6-cylinder DOHC 24-valve liquid-cooled gasoline |
| Total Displacement: 222 cu.in (3.65 L) |
| Rated Engine Power: 335 Hp (248 kW) at 6800 rpm |
| Fuel System Type: Gasoline Direct Injection |
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The Chevrolet LGX is a 3.6-liter, high-output V6 engine
belonging to General Motors’ Gen IV High Feature (HFV6) family. Introduced for
the 2016 model year, this engine represented a comprehensive redesign from its
LFX predecessor, developed as a clean-sheet design to meet escalating demands
for efficiency, power density, and refinement.
The architecture focuses on a robust foundation with a targeted cooling strategy
and a low-friction valvetrain, enabling a high 11.5:1 compression ratio on
regular-grade fuel. It is distinguished by its application of both Direct
Injection and, in many configurations, Active Fuel Management (AFM) cylinder
deactivation, allowing seamless transition between V6 and V4 operation to
optimize fuel economy without compromising the 335 hp output in its highest
state of tune.
Engine Type: 60-degree V6, Gen IV High Feature, naturally aspirated
Displacement: 3.6 L; 222 cu.in (3,649 cc)
Bore: 95.0 mm (3.74 in)
Stroke: 85.8 mm (3.37 in)
Max Power: 335 hp (224-241 kW) @ 6,800 rpm
Compression Ratio: 11.5:1
Firing Order: 1-2-3-4-5-6
Bore Center Distance: 106.0 mm (4.17 in)
The cylinder block is constructed from A319 aluminum
alloy utilizing a precision sand-casting process to ensure structural rigidity
while minimizing mass. Unlike open-deck designs of earlier High Feature engines,
the LGX employs a "targeted" stiffening structure with a deep-skirt design that
extends below the crankshaft centerline for enhanced bottom-end support.
Press-fit cast-iron cylinder liners are integrated into the aluminum casting to
provide a durable bore surface compatible with the low-friction, low-tension
piston rings. The block incorporates a structural aluminum oil pan that serves
as a structural member, increasing overall powertrain stiffness and reducing
Noise, Vibration, and Harshness (NVH). Crankshaft bulkheads are reinforced with
cross-bolted main bearing caps to handle the high cylinder pressures associated
with direct injection.
The cylinder heads are manufactured from cast aluminum
and feature integrated exhaust manifolds cast directly into the head casting.
This integration reduces weight, simplifies assembly, and accelerates catalyst
light-off during cold starts by retaining exhaust heat. The valvetrain utilizes
a Dual Overhead Camshaft (DOHC) configuration with four valves per cylinder.
Valves are actuated by roller-finger followers with hydraulic lash adjusters,
eliminating the need for manual valve adjustments.
The intake valves are constructed from steel, while the exhaust valves are a
high-temperature-resistant material to withstand the elevated thermal loads from
the integrated manifolds. Continuous Variable Valve Timing (VVT) is employed on
all four camshafts, utilizing mid-travel phasers that allow for a wide range of
intake and exhaust overlap adjustment to optimize volumetric efficiency across
the rev range.
The fuel system is a high-pressure Direct Injection
(DI) system operating at a peak pressure of up to 24.0 MPa (3,480 psi). A
mechanical high-pressure fuel pump, driven by a dedicated lobe on the exhaust
camshaft of the rear cylinder head, pressurizes the fuel. The system utilizes
solenoid-actuated injectors mounted directly into the combustion chamber.
The high injection pressure, combined with the 11.5:1 compression ratio, allows
for precise stratification of the air-fuel mixture, resulting in improved
combustion efficiency, increased power output, and reduced emissions during cold
starts. In applications equipped with Active Fuel Management (AFM), the fuel
system seamlessly cuts fuel delivery to the deactivated cylinders while
maintaining oil pressure to the collapsible lifters.
The lubrication system utilizes a variable-displacement
vane-type oil pump. This pump adjusts its output based on engine speed, load,
and temperature, reducing parasitic losses by supplying high flow only when
necessary. The system is designed to support the Active Fuel Management (AFM)
hardware, requiring precise oil pressure to actuate the solenoid-controlled,
collapsible valve lifters in the deactivated cylinders.
A full-flow oil filter is mounted externally for ease of maintenance. Oil
cooling is provided by a liquid-to-oil heat exchanger located at the oil filter
housing, utilizing engine coolant to stabilize oil temperature rapidly.
The cooling system employs a "targeted" or
split-cooling architecture. The engine features a water jacket that prioritizes
cooling for the cylinder heads and integrated exhaust manifolds, allowing the
cylinder block to warm up more rapidly. This configuration reduces friction
during warm-up and improves overall thermal efficiency.
A high-efficiency electric water pump is utilized in many transverse
applications, allowing for residual heat extraction after engine shutoff. The
system is pressurized and utilizes a cross-flow aluminum radiator in vehicle
applications to maintain consistent operating temperatures under high-load
conditions such as towing or performance driving.
| Intake and Exhaust Systems |
Intake Manifold: A two-stage composite intake manifold
is utilized, incorporating a variable-length intake runner system. Short runners
are utilized for high-rpm power, while long runners improve low-end torque and
cylinder filling.
Exhaust System: Stainless steel exhaust manifolds are integrated into the
cylinder heads. Downstream, the system utilizes a close-coupled catalytic
converter to meet stringent emissions standards.
A direct ignition system with individual coil-on-plug
(COP) units is used. Each coil is mounted directly over the spark plug and is
controlled by the Engine Control Module (ECM) for precise spark timing.
Active Fuel Management (AFM): The LGX incorporates
cylinder deactivation technology. Under light load conditions, the engine
deactivates cylinders 1, 2, 3, and 4, effectively operating as a V4. The system
utilizes special valve lifters that collapse when oil pressure is routed through
solenoids, preventing the valves from opening while the fuel injectors for those
cylinders are shut off.
Crankshaft: A forged steel crankshaft is employed to ensure durability at the
maximum engine speed of 7,200 rpm and to withstand the high mechanical loads
associated with the 11.5:1 compression ratio.
Overall Length: 737 mm (29.0 in)
Overall Width: 899 mm (35.4 in)
Overall Height: 660 mm (26.0 in)
Weight (dry, as configured): 167 kg (368 lb)
Oil Capacity (with filter): 5.7 L (6.0 qt).
Oil Type: SAE 5W-30; meeting dexos1 specification.
Coolant Capacity (engine only, varies by vehicle): 9.5 L (10.0 qt).
Spark Plug Type: Iridium-tipped, 41-124 (ACDelco).
Spark Plug Gap: 0.95-1.10 mm (0.037-0.043 in).
Spark Plug Replacement Interval: 161,000 km (100,000 mi).
Drive Belt Tension: Automatic tensioner, no adjustment required.
Engine Oil Change Interval: As determined by Oil Life Monitoring System, up to
12,000 km (7,500 mi) under normal conditions.
Cylinder Head Bolts (M12 x 1.5): 30 Nm (22 lb-ft)
Main Bearing Cap Bolts (M10): 25 Nm (18 lb-ft)
Connecting Rod Cap Nuts (M9): 20 Nm (15 lb-ft)
Camshaft Bearing Cap Bolts (M6): 10 Nm (89 lb-in)
Intake Manifold Bolts (M6): 10 Nm (89 lb-in)
Exhaust Manifold Nuts (M8), Stage 1: 10 Nm (89 lb-in)
Exhaust Manifold Nuts (M8), Stage 2: 20 Nm (15 lb-ft)
Spark Plugs: 15 Nm (11 lb-ft)
Oil Pan Bolts (M6): 12 Nm (106 lb-in)
Crankshaft Balancer Bolt (M16): 110 Nm (81 lb-ft)
Chevrolet Camaro (V6): 2016-2024 (335 hp / 284 lb-ft)
Chevrolet Blazer: 2019-Present (308 hp / 270 lb-ft)
Chevrolet Colorado: 2017-2022 (308 hp / 275 lb-ft)
GMC Canyon: 2017-2022 (308 hp / 275 lb-ft)
Chevrolet Traverse: 2018-Present (310 hp / 266 lb-ft)
Cadillac CT5: 2020-Present (335 hp / 285 lb-ft)
Cadillac CT6: 2016-2020 (335 hp / 285 lb-ft)
Cadillac XT5: 2017-Present (310 hp / 271 lb-ft)
Cadillac XT6: 2020-Present (310 hp / 271 lb-ft)
Buick LaCrosse: 2017-2019 (310 hp / 282 lb-ft)
Buick Enclave: 2018-Present (310 hp / 266 lb-ft)
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