Chevrolet LT7 Specifications
| Engine Model: Chevrolet LT7 |
| Engine Type: 4-cycle 8-cylinder 32-valve twin-turbocharged liquid-cooled gasoline |
| Total Displacement: 333.4 cu.in (5.46 L) |
| Rated Engine Power: 1,064 Hp (793 kW) at 7000 rpm |
| Fuel System Type: Direct injection and port fuel injection (PFI) |
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The Chevrolet LT7 is a 5.5-liter, twin-turbocharged,
90-degree V8 engine representing the zenith of General Motors’ internal
combustion development. As the flagship powerplant for the 2025 and 2026
Chevrolet Corvette ZR1, it marks a historic departure as the first
factory-turbocharged engine in Corvette history.
Derived from the naturally aspirated LT6, the LT7 is engineered for extreme
forced induction, utilizing a flat-plane crankshaft, dual-overhead camshafts,
and a sophisticated hybrid fuel delivery system. It stands as the most powerful
production V8 ever produced by an American automaker, delivering a combination
of high-rpm ferocity and forced-induction torque.
Engine Type: 90-degree V8, Dual Overhead Cam (DOHC), 4 valves per cylinder
Aspiration: Twin-turbocharged with 76 mm mono-scroll turbochargers
Displacement: 5.5 L (5,463 cc / 333.4 cu.in)
Bore: 104.25 mm (4.10 in)
Stroke: 80.0 mm (3.15 in)
Compression Ratio: 9.8:1
Crankshaft: Flat-plane design with forged steel construction
Firing Order: 1-4-3-8-7-6-5-2
Horsepower: 1,064 hp (793 kW) @ 7,000 rpm
Torque: 828 lb-ft (1,123 Nm) @ 6,000 rpm
Redline: 8,000 rpm
Maximum Boost Pressure: 20 psi (1.38 bar) under normal conditions
Maximum Boost Pressure: 24 psi (1.66 bar) under maximum transient conditions
The LT7 utilizes a cast aluminum cylinder block with a
90-degree vee angle. This block is a structural evolution of the LT6
architecture, featuring enhanced strength for turbocharging applications. It
incorporates pressed-in iron cylinder liners to ensure durability under high
cylinder pressures. The deep-skirt design provides exceptional rigidity,
supporting the flat-plane crankshaft and the high-output valvetrain.
The block is optimized for a dry-sump lubrication system, with dedicated oil
galleries machined to support the increased oil flow demands of the
turbochargers and high-performance piston cooling jets. Main bearing caps are of
a high-strength, fracture-split design to maintain crankshaft alignment under
sustained high-load conditions.
The cylinder heads are cast from high-strength aluminum
alloy and utilize a dual-overhead camshaft (DOHC) arrangement with four valves
per cylinder. Unlike the LT6, the LT7 employs unique head castings featuring
larger combustion chambers to accommodate the reduced compression ratio of
9.8:1. The intake and exhaust ports are redesigned to optimize flow for forced
induction. The valvetrain consists of lightweight, hollow-stem valves to
facilitate the 8,000 rpm redline.
The intake valves measure 38.9 mm (1.53 in) in diameter, while the sodium-filled
exhaust valves measure 34.0 mm (1.34 in) to manage high exhaust temperatures
generated under boost. Camshaft profiles are specific to the LT7, balancing
high-rpm power delivery with the demands of positive manifold pressure. The
valvetrain is secured by advanced hydraulic lash adjusters and high-rigidity
roller finger followers.
The LT7 employs a hybrid fuel injection system,
combining direct injection (DI) and port fuel injection (PFI) to optimize power,
drivability, and emissions. This dual-injection strategy ensures adequate fuel
delivery at high engine speeds and loads while maintaining combustion stability.
The port fuel injectors assist in keeping the intake valves free of deposits and
provide additional fuel mass to support the engine’s power output.
The direct injection system operates at high pressure, precisely metering fuel
into the combustion chamber to enable a high compression ratio relative to the
boost pressure. This system allows the engine to achieve its specific output
while maintaining smooth operation across the rev range.
The LT7 utilizes a sophisticated dry-sump lubrication
system designed to maintain consistent oil pressure under extreme lateral
acceleration forces common in track driving. The system features an 8-quart (7.5
L) total capacity. A critical advancement for this engine is the inclusion of a
seventh scavenge stage dedicated specifically to evacuating oil from the
turbocharger cartridges.
This ensures rapid oil return and prevents oil accumulation in the turbo
housings during high-g cornering or braking. The oil pan is a structural
component, contributing to chassis rigidity. A high-efficiency oil cooler is
integrated to maintain optimal oil temperature during sustained high-performance
operation. The system utilizes a variable-displacement oil pump to reduce
parasitic losses while ensuring adequate flow to the main bearings, piston
cooling jets, and turbochargers.
The cooling system is engineered to manage the thermal
load of a twin-turbocharged V8 producing over 1,000 hp. It utilizes a
high-capacity water pump and a dual-circuit architecture. One circuit manages
engine block and cylinder head cooling, while a secondary circuit is dedicated
to charge air cooling for the twin turbochargers. An air-to-liquid intercooler
system reduces intake air temperatures post-compression.
The Corvette ZR1’s chassis integration includes multiple radiators - a central
main radiator, two auxiliary radiators in the front corners, and a dedicated
intercooler radiator. This configuration ensures thermal stability during
high-speed track events, preventing heat soak and maintaining consistent power
output.
| Intake and Exhaust Systems |
Intake System: The engine features a dual air intake
system drawing air through inlets integrated into the rear quarter panels. This
provides a direct, high-volume air path to the 76 mm mono-scroll turbochargers.
Exhaust System: The turbochargers are integrated directly into the exhaust
manifolds, a design that reduces the distance exhaust gases travel to the
turbine wheels, minimizing lag. The exhaust system utilizes lightweight Inconel
in critical high-temperature areas to withstand the elevated thermal stresses.
Intelligent Anti-Lag: The calibration incorporates a
ZR1-specific intelligent anti-lag system. This system adapts to driving style,
maintaining boost pressure during off-throttle conditions such as braking for
corners to ensure immediate power delivery upon re-application of throttle.
Ignition System: A high-energy ignition coil-per-cylinder system provides
precise spark control necessary for high cylinder pressures under maximum boost.
Dimensions and Weight
Length: 29.2 in (741 mm)
Width: 34.5 in (876 mm)
Height: 28.0 in (711 mm)
Weight (dry): 512 lb (232 kg)
The engine’s dimensions are dictated by the DOHC cylinder heads and the
integrated turbocharger packaging, designed to fit within the mid-engine
architecture of the C8 Corvette.
Engine Oil Capacity (with filter): 8.0 qt (7.5 L).
Oil Viscosity: SAE 0W-40 or 5W-50 for track use, meeting GM dexosR
specification.
Coolant Capacity: Approximately 18.0 qt (17.0 L) for total system, including
intercooler circuit.
Spark Plug Gap: 0.030 in (0.76 mm).
Valve Lash: Hydraulic lifters; no periodic adjustment required.
Inspection Intervals: Spark plugs recommended for replacement every 60,000 miles
(96,000 km); drive belts and cooling system hoses to be inspected annually.
Cylinder Head Bolts (Initial Pass): 59 lb-ft (80 Nm)
Cylinder Head Bolts (Final Angle): 90 deg + 90 deg
Main Bearing Cap Bolts (M10): 48 lb-ft (65 Nm) + 60 deg
Connecting Rod Bolts: 37 lb-ft (50 Nm) + 70 deg
Camshaft Cap Bolts: 106 lb-ft (144 Nm)
Crankshaft Damper Bolt: 74 lb-ft (100 Nm) + 140 deg
Intake Manifold Bolts: 89 lb-ft (121 Nm)
Exhaust Manifold to Turbocharger Studs: 35 lb-ft (47 Nm)
Turbocharger Mounting Hardware: 45 lb-ft (61 Nm)
Chevrolet Corvette ZR1 (C8): 2025-Present. This
application represents the standard installation of the LT7 engine in the
mid-engine sports car platform, producing 1,064 hp.
Chevrolet Corvette ZR1X: A variant utilizing the LT7 engine as part of a
hybridized powertrain. In this configuration, the internal combustion engine is
combined with a front-axle electric drive unit to produce a combined system
output of 1,250 hp, leveraging the LT7’s thermal efficiency and power density
for a high-performance “hypercar” application.
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