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Chevrolet LT4 Specifications
| Engine Model: Chevrolet LT4 |
| Engine Type: 4-cycle 8-cylinder OHV 16-valve supercharged liquid-cooled gasoline |
| Total Displacement: 376 cu.in (6.16 L) |
| Rated Engine Power: 650 Hp (477 kW) at 6400 rpm |
| Fuel System Type: Direct fuel injection |
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| General Technical Data |
The Chevrolet LT4 is a 6.2-liter, V8,
supercharged gasoline engine. It represents the pinnacle of the small
block V8 lineage for its production era, belonging to the Generation V
LT engine family. Designed and manufactured for the highest-performance
Chevrolet vehicles, this engine serves as the powerplant for supercars
and ultra-high-performance models. The LT4 integrates a 1.7-liter
Roots-type supercharger with an integrated charge air cooling system
directly onto its aluminum block.
It retains a direct injection fuel system and an advanced active fuel
management system, but with components strengthened to handle
significant boost pressure. The engine's design objective is to deliver
extreme Hp and torque figures while maintaining drivability, meeting
emissions standards, and offering a level of efficiency uncommon in
forced induction engines of its output class.
Engine Type: 90-degree V8, gasoline, supercharged, overhead valve
(OHV/pushrod)
Displacement: 6162 cc (376.0 cubic inches)
Bore: 103.25 mm (4.065 inches)
Stroke: 92.0 mm (3.622 inches)
Compression Ratio: 10.0:1
Firing Order: 1-8-7-2-6-5-4-3
Cylinder Numbering: Left bank (driver side): 1-3-5-7; Right bank
(passenger side): 2-4-6-8
Maximum Power Output: 477 kW (650 Hp) at 6400 rpm
Maximum Torque: 881 Nm (650 lb-ft) at 3600 rpm
Fuel Type: Unleaded premium gasoline, 93 AKI (98 RON) minimum
Oil Quality Specification: GM dexos2 5W-40 or equivalent
Engine Oil Capacity (including filter): 9.7 liters (10.25 US quarts)
(dry sump system)
Coolant Capacity (total system): 16.5 liters (17.44 US quarts) (total
for engine and intercooler circuits).
| Cylinder Block |
The LT4 uses a cast aluminum cylinder block with cast iron cylinder liners. This block is derived from the LT1 architecture but is strengthened with additional bulkhead material and improved main bearing cap geometry to withstand the forces of supercharging. It features six-bolt, cross-bolted main bearing caps. The crankshaft is a forged steel unit with induction-hardened journals.
Connecting rods are forged powdered metal units with fractured-split big ends. Pistons are forged aluminum alloy, designed with a specific contour to achieve the 10.0:1 compression ratio under boost, and feature an anodized top ring land and skirt coating for durability. The camshaft is a steel billet grind with a profile optimized for forced induction.
| Cylinder Head and Valves |
The LT4 employs cast aluminum cylinder heads with large, rectangular intake ports and machined, high-flow combustion chambers. These heads are secured with 11 mm diameter head bolts for increased clamping force. Each cylinder operates with a single 2.13-inch (54.1 mm) titanium intake valve and a single 1.59-inch (40.4 mm) sodium-filled exhaust valve.
The use of titanium for the intake valves reduces reciprocating mass. Valve actuation uses hydraulic roller lifters, hardened pushrods, and investment-cast rocker arms with a 1.8:1 ratio (higher than standard LT1). The valve springs are a high-rate design to control the valves at elevated rpm under boost. The cylinder head gasket is a multilayered steel (MLS) design capable of sealing high cylinder pressures.
| Fuel System |
The fuel system is a direct injection design, operating at pressures up to 200 bar (2900 psi). A high-pressure fuel pump, driven by the camshaft, supplies fuel to a common rail. Eight individual solenoid-activated injectors are mounted centrally within the combustion chamber. This system is supplemented by a secondary port fuel injection system in later applications (e.g., C7 Z06) to provide additional fuel under high load and mitigate carbon buildup on intake valves.
The combined system is managed by a 32-bit Engine Control Module (ECM). The ECM integrates data from a wide range of sensors, including a manifold absolute pressure (MAP) sensor reading boost, multiple temperature sensors, and dual wide-band oxygen sensors.
| Lubrication System |
The LT4 employs a dry-sump lubrication system as standard equipment. This system consists of a multiple-stage oil pump (one pressure stage, multiple scavenge stages), an external oil reservoir (tank), and a separate oil cooler. The scavenge pumps actively remove oil from the crankcase, ensuring positive oil pressure during high lateral and longitudinal acceleration and reducing windage losses.
Oil is fed under pressure from the tank through a dedicated oil filter and into the main gallery. The system provides targeted cooling to the piston undersides via jets and ensures a constant supply to the supercharger's internal gears and bearings. The large external oil tank provides significant oil capacity and aids in heat rejection.
| Cooling System |
The cooling system is a complex, multi-circuit design. A primary circuit handles engine coolant via a belt-driven water pump and a high-capacity radiator. A separate, independent circuit is dedicated to the supercharger's liquid-to-air intercooler system. This intercooler circuit uses its own electric pump and a low-temperature heat exchanger to chill the intake charge after compression, significantly increasing air density and reducing the tendency for detonation.
A third circuit may cool the transmission and differential fluids on track-focused models. The engine employs an electronically controlled thermostat for precise thermal management. All circuits contribute to managing the substantial heat generated by supercharged operation.
| Supercharger System |
The defining feature is an Eaton 1.7-liter, four-lobe Roots-type supercharger. It is mounted directly atop the intake valley and is driven by the crankshaft via an 8-rib serpentine belt. The supercharger housing integrates a liquid-to-air intercooler system.
The rotors are coated for low friction and high efficiency. The supercharger produces a maximum of 9.4 psi (0.65 bar) of boost pressure. A bypass valve routes excess boost back to the inlet under low-load conditions for improved efficiency.
| Ignition System |
The engine uses a coil-near-plug, distributorless ignition system. Eight individual ignition coils fire iridium-tipped spark plugs. The ECM constantly monitors for detonation via multiple knock sensors and can adjust ignition timing individually per cylinder in real-time to protect the engine while maximizing performance under boost.
| Engine Control and Electronics |
Management is handled by a powerful, tri-core Engine Control Module (ECM). This unit executes torque-based control strategies, integrating inputs from over 20 engine sensors. It manages the complex interaction between direct and port injection, supercharger bypass, variable valve timing, active fuel management, and electronic throttle control. The ECM features multiple maps for different fuel qualities and driving modes.
| Dimensions and Weight |
Length (from bellhousing to supercharger snout): 850 mm (33.46 inches)
Width (across cylinder heads): 780 mm (30.71 inches)
Height (from oil pan to supercharger lid): 760 mm (29.92 inches)
Dry Weight (complete engine, dry sump): 260 kg (573 lbs)
| Maintenance Data |
Recommended Service Intervals:
Engine Oil and Filter Change: 12000 km (7500 miles) or 12 months under
normal conditions; drastically reduced for competitive track use.
Supercharger Intercooler Coolant Service: Check and refill per
manufacturer schedule; replace at 240000 km (150000 miles).
Air Filter Element Replacement: Inspect every oil change; replace as
required, especially in dusty conditions.
Spark Plug Replacement: 97000 km (60000 miles).
Coolant Replacement (Engine and Intercooler Circuits): 240000 km (150000
miles) or 5 years.
Serpentine Drive Belt Inspection: Frequent inspection due to high
supercharger load; replace at first sign of wear.
Fluid Specifications and Capacities:
Engine Oil: SAE 5W-40, full synthetic meeting GM dexos2 specification.
Engine Coolant: Dex-Cool or equivalent OAT coolant.
Supercharger Intercooler Coolant: Specific GM-approved intercooler
fluid.
Fuel: Premium unleaded, 93 AKI octane minimum.
| Tightening Torques |
Cylinder Head Bolts: Torque-to-yield, single-use bolts. Tighten in the
specified sequence.
Step 1: 30 Nm (22 lb-ft)
Step 2: Tighten an additional 90 deg of rotation
Step 3: Tighten an additional 90 deg of rotation
Main Bearing Cap Bolts (vertical): 50 Nm (37 lb-ft) plus an additional
77 deg
Main Bearing Cap Cross-Bolts: 20 Nm (15 lb-ft) plus an additional 50 deg
Connecting Rod Cap Bolts: 25 Nm (18 lb-ft) plus an additional 85 deg
(lubricate threads with engine oil)
Spark Plugs: 20 Nm (15 lb-ft)
Supercharger to Intake Manifold Bolts: 25 Nm (18 lb-ft)
Crankshaft Balancer Bolt: 260 Nm (192 lb-ft) plus an additional 140 deg
Oil Pan Bolts: 25 Nm (18 lb-ft)
| Vehicle Applications |
The Chevrolet LT4 engine was installed in
the following vehicles:
Chevrolet Corvette Z06 (C7 generation, 2015-2019)
Cadillac CTS-V (third generation, 2016-2019)
Chevrolet Camaro ZL1 (sixth generation, 2017-2023)
Cadillac CT5-V Blackwing (2022-present)
Chevrolet Corvette Z06 (C8 generation, 2023-present, with significant
redesign)
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