The gear reduction also allows for the use of smaller cam drive gears, resulting in a more compact head. The cam drive gears and chain are located under the powerhead where they run in an oil bath for superior lubrication. The location also lowers the engine's center of gravity. A hydraulic cam chain tensioner is included to keep the cam chain properly adjusted for maintenance-free service. The fuel system consists of a diaphragm pump driven from the cam drive, and a water-cooled fuel chiller that's incorporated ahead of the pressure regulator.
Cool fuel is less subject to percolation and vapor lock problems.
Fuel-related components are located on the intake manifold, the coolest location on the engine. Additional water-cooled components include the vapor separator, voltage regulator and the fuel rail at the injectors. Each injector has four orifices to distribute the atomized fuel more evenly in the combustion chamber. The sequential, multi-port injection system is designed to put fuel into the manifold at the intake valve. In fact, these are among the few engines that are claimed to meet CARB's stringent 2008 emissions standards.