Chevrolet Corvette ZR1 LS9 Engine Specifications - Domestic Exotica

Even in this high-tech facility, lots of good, old-fashioned marking paint is used throughout the process. After the blower is installed, the builder marks the back of the unit to show that the protective plastic cover was removed. Usually it's just a dot, but we used an X this time. So if you're lucky enough to own a ZR1, check your blower. If you see this mark, then this is your engine.

Force-feeding duties on the LS9 are performed by a sixth-generation-design R2300 supercarger from Eaton, with a Corvette-specific case design. The four-lobe rotor design, which also features an abradable powdercoating, promotes quieter and more efficient performance. The unit displaces 2.3 liters to ensure ample air volume at high rpm. Maximum boost pressure is 10.5 psi, a level that gets the most out of the engine while ensuring reliability.

The LS9 employs a center-feed fuel line system to ensure even fuel flow between cylinders (each fed by a high-capacity 48 lb-hr fuel injector) while creating less noise. More importantly, the powertrain team developed a dual-pressure fuel arrangement. The system operates at 250 kPa during idle and low-speed operation to enhance drivability, but then cranks up to 600 kPa to meet the requirements of higher speed and WOT conditions.

With the blower installed and torqued down, the charge air cooler is then installed. The LS9 employs a liquid-to-air charge cooling system; inlet air temperature is reduced by up to 140 degrees F for a denser intake charge. The design of the supercharger case and the integrated charge cooling system were dictated by the space and dimensions 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. It's only slightly taller than the non-supercharged 6.2L engine.

The GM Performance Build Center's motto is "One Builder for One Engine," so you can be certain that every builder takes his job very seriously, and even more so since his name goes onto the side of the blower. And of course GM has a template to make sure the builder gets his nameplate in just the right spot.

Once the supercharger assembly is installed, the engine is sealed and pressure-tested. Air is forced into the oil and water passages, and the computer makes sure there are no leaks. If the pressure isn't held, the builder pinpoints the location of the leak before the engine can move on.

The LS9 uses the same exhaust manifolds as the LS7. These pieces are trick, fabricated from 18 separate parts, and very efficient. "One of the last parts designed for the LS7 was the manifold," our man Guard told us. "The team did an excellent job to get it to crack 500 hp." When it came to the LS9, Guard said it did not provide "a significant cork."

The LS9's flywheel is put on using a two-pass system-each is marked with paint on the final pass to show it is finished. Note that the flywheel is attached to the crank flange with nine bolts instead of the usual six, providing greater clamping strength.

Speaking of greater clamping strength, the LS9's dual 260mm disc clutch spreads the engine's torque load over a wider area to provide just that while maintaining easy clutch pedal effort. The assembly itself is much heavier than the LS7 clutch, so GM uses an air-assisted lift to help the builder put it in place for alignment and final installation.