What's so special about direct injection? As opposed to port fuel injection, which injects fuel ahead of the intake valve into the intake manifold (resulting in a "wet" manifold), direct injection delivers a fuel mist directly into the combustion chamber at extremely high pressure. This results in better mixing, more complete combustion, lower emissions, and more power: 304 hp and 273 pound-feet of torque.
In addition, the injection event may be timed on its own, independent of intake valve operation. This allows higher compressions ratios, which equals greater efficiency, and it also prevents dangerous pre-ignition (pinging) common in turbocharged and high-compression engines. Indeed, this high-performance powerplant is completely happy running on regular unleaded fuel. GM also employs direct injection on its 2.0-liter EcoTec four-cylinder found under the hoods of the Saturn Sky Red Line, Pontiac Solstice GXP, Chevrolet Cobalt SS, and Chevrolet HHR SS.--Colin Mathews