Volkswagen has developed a combined supercharger-turbocharger system that will boost power and fuel economy of small gasoline engines. The SuperTurbo Compounding system will make its debut on the 2006 VW Golf. VW claims a 1.4-liter gasoline engine with SuperTurbo can develop 170 horsepower and 199 pound-feet of torque, compared with VW’s existing 2.0-liter four-cylinder, which delivers 150 hp and 148 lb-ft of torque. The system has been developed by supercharger supplier Eaton. It is claimed the SuperTurbo eliminates turbo lag, while boosting overall power and fuel economy by 15 to 20 percent. Eaton said a car fitted with the system will be shown at the Frankfurt auto show. VW’s plans call for widespread use of the system, starting with a 1.4-liter direct-injection engine that is expected to debut in the 2006 Golf before heading into other VW models. Later, 1.6-liter and 2.0-liter versions will also be produced. The concept is not new. Combined superchargers and turbochargers were common on World War II-era aircraft engines, and an Abarth-developed system was used on the 1985 Lancia Delta S4 rally car.