NOVELTY - The method involves heating intake air via a gas-to-gas heat exchanger (34) that is in communication with exhaust gases, and heating a fluid with the intake air via a gas-to-liquid heat exchanger (36), where the fluid flows through a turbocharged engine (10). The fluid is engine oil, engine coolant or transmission oil. The amount of heated intake air is adjusted via an air bypass valve. The gas-to-gas heat exchanger is positioned upstream of an exhaust catalyst. The exhaust catalyst is cooled when the turbocharger engine is in operation and boost is greater than a threshold value.    USE - Method for heating a turbocharged engine in a vehicle e.g. automobile.    ADVANTAGE - The method enables heating intake air with exhaust heat and then transferring some of the heat to a power train fluid such as engine oil, so that the fluid is heated while reducing energy losses due to the viscosity of the fluid in addition to reducing combustion chamber heat loss. The heated intake air is cooled via the heat exchange with the power train fluid with warmer than ambient air such that engine pumping losses are reduced. The method enables decreasing the knock caused by heated intake air during a cold start with the engine warming up thus achieving synergistic operation. The method enables the air bypass valve to flow intake air through a series of heat exchangers in order to heat engine intake air as well as a power train fluid, so that fuel economy is increased and the intake stroke pumping work is decreased, thus expediting the heating of power train fluid circulating through the engine to a desired temperature for warmed-up engine operation, and hence reducing viscous energy losses due to friction.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a heating system for an engine comprising a throttle.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of an engine including a gas-to-gas heat exchanger and a gas-to-liquid heat exchanger.    Turbocharged engine (10)    Control system (14)    Gas-to-gas heat exchanger (34)    Gas-to-liquid heat exchanger (36)    Vehicle system (100)