Because the pressurized air is hotter than naturally aspirated air, the LS9 employs a liquid-to-air charge cooling system to reduce inlet air temperature after it exits the supercharger-reducing the inlet air temperature by up to 60 degrees C (140 F). Cooler air is denser and allows the engine to make the most of its high-pressure air charge. The charge cooling system includes a dedicated coolant circuit with a remote-mounted pump and reservoir.
The design of the supercharger case and its integrated charge cooling system was driven by the space and dimensions afforded under the Corvette's hood. To that end, the charge cooler was designed as a "dual-brick" system, with a pair of low-profile heat exchangers mounted longitudinally on either side of the supercharger. Coupled with the supercharger itself, this integrated design mounts to the engine in place of a conventional intake manifold and is only slightly taller than a nonsupercharged 6.2L engine. The air inlet and rotor drive pulley are positioned at the front of the supercharger.
Additional Engine Details
Oiling system: The LS9 uses a dry-sump oiling system that is similar in design to the LS7's system, but features a higher-capacity pump to ensure adequate oil pressure at the higher cornering loads the ZR1 is capable of achieving. An oil-pan-mounted oil cooler is integrated, too, along with piston-cooling oil squirters located in the cylinder block. The expanded performance envelope of the Corvette ZR1 required changes to the dry sump system also used in the Z06. System capacity is increased and scavenge performance improved to meet the demands of Chevrolet's highest-performance sports car.
Water pump: To compensate for the heavier load generated by the supercharger drive system, an LS9-specific water pump with increased bearing capacity is used.
Accessory drive system: In order to package the accessory drive system in the Corvette's engine compartment, the supercharger drive was integrated into the main drive system. This required a wider 11-rib accessory drive system to be used with the LS9 in order to support the load delivered by the supercharger.
Fuel system: The LS9 uses high-capacity 48-lb/hr fuel injectors with center-feed fuel lines. The center-feed system ensures even fuel flow between the cylinders with less noise. In order to ensure fuel system performance during low-speed operation, as well as under the extreme performance requirements of wide open throttle (WOT), a dual pressure fuel system was developed. This system operates at 250 kPa at idle and low speed, and ratchets up to 600 kPa at higher speed and WOT conditions.
Throttle body: An 87mm, single-bore throttle body is used to draw air into the engine. It is electronically controlled.
Rocker covers/ignition coils: Unique rocker covers with new, direct-mount ignition coils are used. Other Gen IV engines, such as the LS3, feature coil packs mounted to a bracket. The LS9's direct-mounted coils offer a cleaner appearance and a shorter lead between the coil and spark plug.
Beauty cover: A special engine cover is attached to the top of the LS9. It surrounds the intercooler, which is visible through a hood window, accenting the supercharger while simultaneously reducing noise. The cover has "LS9 SUPERCHARGED" script on the left and right sides, along with a debossed Corvette crossed-flags emblem on the front.
New Six-Speed Manual Transmission
The Corvette ZR1's LS9 engine is backed by a Tremec TR6060 six-speed manual transmission, with a twin-disc clutch system. It is based on the proven T56 six-speed, but upgraded to handle the LS9's torque output and delivers improved shift quality
The twin-disc clutch system provides exceptional clamping power, while maintaining an easy clutch effort. The system employs a pair of 260mm discs, which spreads out the engine's torque load over a wider area, enabling tremendous clamping power to channel the LS9's torque. It also dissipates heat better and extends the clutch life (in normal driving).