For more than 10 years, Suzuki has relied on its 2.0-liter 4-cylinder engine as the workhorse in its powertrain lineup—it is the base power plant for the majority of the automaker’s U.S. sales volume. Although its respectable output of 143 hp (and 136 lb-ft of torque) has served well in small car applications, Suzuki’s engineering staff was a bit concerned the engine would not perform well in midsize sedan or crossover applications as they require more power. These concerns forced the team to develop an even more powerful 2.4-liter four (166 hp @ 6,000 rpm and 162 lb.-ft. of torque @ 4,000 rpm) that debuts as the new base power plant for the ’09 Grand Vitara crossover.
The 2.4-liter shares the bore pitch from the 2.0-liter, and follows its example with an aluminum block, cylinder head, oil pan and timing chain cover, and a forged carbon steel crankshaft. Unlike the 2.0-liter, however, the new engine features the first use of balance shafts on any Suzuki motor. These help reduce vibration, but increased weight of the engine by 4 kg. In an effort to further limit the weight increases, engineers designed the lower crankcase to be made from aluminum (versus cast iron on the 2.0-liter engine) with steel inserts to support the crankshaft’s micro-groove bearings—further reducing noise and vibration. Timing chain tensioner guides and the idler pulley are constructed from plastics, and hollow camshafts cut weight, reduce reciprocating mass, and increasing oil flow for better lubrication.
A resin intake manifold adjusts the length of the intake track in two stages, depending on RPM and throttle angle, improving torque. Tumble control valves are used to improve cold start emission performance.—KMK