Inside The LS7
The LS7 reintroduced the 427ci engine to the Corvette lineup in 2006. Unlike the previous 427 engine, which was a big-block design, the 7.0-liter LS7 is a small-block V-8-the largest displacement small-block ever produced by Chevrolet and GM, and a tribute to its 50 years as a performance icon.
The Z06-only LS7 is easily identified under the hood by red engine covers with black lettering. The LS7 shares the same basic Gen IV V-8 architecture as the Corvette's 6.0-liter LS2, but it uses a different cylinder block casting with pressed-in steel cylinder liners to accommodate the engine's larger diameter, 104.8mm-wide cylinder bores. Compared with the LS2, the LS7 also has a different front cover, oil pan, exhaust manifolds, and cylinder heads, among many other components.
Internally, the LS7's reciprocating components make use of racing-derived lightweight technology, including titanium connecting rods and intake valves, to help boost horsepower and rpm capability. The rpm fuel shut-off limit is 7,100 rpm. The LS7's details include:
* Dry-sump oiling system
* Unique cylinder block casting with large, 104.8mm bores and pressed-in cylinder liners
* Forged steel main bearing caps
* Forged steel crankshaft
* Titanium connecting rods with 101.6mm stroke
* Cast aluminum flat-top pistons
* 11.0:1 compression
* High-lift camshaft
* Racing-derived CNC-ported aluminum cylinder heads with titanium intake valves and sodium-filled exhaust valves
* Low-restriction air intake system
* Hydroformed exhaust headers with unique "quad flow" collector flanges
Z06 Drivetrain And Chassis
The Corvette Z06's powertrain and drivetrain systems are matched to the LS7's performance capability. The light, four-into-one headers discharge into new, close-coupled catalytic converters and through to new bi-modal mufflers. The mufflers each feature a vacuum-actuated outlet valve, which controls exhaust noise during low-load operation but opens for maximum power.
At the rear of the LS7 engine, a single-mass flywheel and lightweight, high-capacity clutch channel torque to the rear transaxle. The six-speed manual transmission has been strengthened to handle the LS7's increased torque load. The transmission includes a pump that sends transmission fluid to the front radiator for cooling. Upon its return, the fluid removes additional heat from the differential lube before returning to the transmission. The six-speed transmission connects to a limited-slip differential with enlarged ring-and-pinion gears. Stronger axle half-shafts with tougher universal joints transmit power to the rear wheels.
The Z06 has a unique aluminum body structure for optimum stiffness and light weight for the fixed-roof body style. Perimeter rails are one-piece hydroformed aluminum members featuring cast suspension nodes, which replace many welded steel components on other Corvette models. Other castings, stampings, and extrusions are combined into the innovative structure with state-of-the-art manufacturing technologies.
Advanced structural composites featuring carbon fiber are bonded to the aluminum structure. The wider front wheelhouses, for example, are carbon composites, and the passenger compartment floors combine carbon-fiber skins with an ultra-lightweight balsa wood core.
The Z06 has a new magnesium cradle that serves as the attachment point for the engine and some front suspension components. Magnesium is lighter than aluminum yet incredibly strong. The magnesium cradle helps improve the front-to-rear weight distribution, as do carbon-fiber front fenders and wheelhouses. Engineers also moved the battery from underhood to a position in the rear cargo area, behind one of the rear wheels.
The mass reductions are offset by some added performance enablers, including dry-sump lubrication, exhaust system with outlet valves, larger wheels and tires, larger brakes, and larger roll stabilizers.