The main difference is the LE9 is an E85 flexible-fuel compatible engine. This version is basically the same as LE5 Ecotec. While the cylinder head cover is still made of aluminum, the intake manifold is made of plastic, saving weight and cost.
The throttle body is also electronically controlled (ETC - Electronic Throttle Control), where is no physical connection between the accelerator pedal and the engine throttle. The 2.4 Ecotec uses a conventional sequential port fuel injection controlled by ECM (an all-new Engine Control Module). The ignition system features central-located spark plugs and a coil-on-plug design. The valvetrain is fitted with hydraulic roller finger followers. Electronically controlled variable valve timing is applied for both intake and exhaust camshafts. Unlike the original 2.2 Ecotec, the 2.4l LE5 version has variable valve technology. The engine features a chain-driven dual overhead camshaft design. On top, there is a cast aluminum cylinder head with four valves per cylinder. They spin at twice the speed of the engine crankshaft to cancel the second-order vibrations. The new engine got twin counter-rotating balance shafts. Oil jets or oil spray squirters continuously spray the underside of each piston, increasing longevity by reducing engine operating temperatures. Engineers introduced into the block design piston-cooling oil jets. In July 2007, GM switched to C70 forged connecting rods. Early engines were equipped with GKN forged connecting rods. The engine block also features direct-mounted accessories. It has a cast aluminum cylinder block with a highly rigid lower crankcase (a reinforced "Gen II" block). Like the original 2.2L I-4, the 2.4 Ecotec is an all-aluminum engine. The 2.4l Ecotec LE5 features not only increased displacement but also some new technologies that make it much better in terms of power and efficiency. At the basis of the 2.4 LE5 is the 2.2L Ecotec, which has proven itself to be an excellent engine and was one of GM's highest volume engines at that time.