Methods and systems for reducing the temperature of the charge air provided to a turbocharged internal combustion engine. A supercharger is installed on the air intake path, upstream the turbocharger's compressor. A secondary charge air cooler is installed between the supercharger and the main compressor. This over-compresses the intake air, so that an expansion turbine installed downstream the turbocharger's compressor can cool the charge air and still provide sufficient charge air pressure into the intake manifold.