Abstract: A portable compressed air system includes a housing, and a diesel engine having a predetermined torsional inertia, a predetermined cranking speed, and a predetermined idle speed. A centrifugal compressor is flexibly coupled in motive force receiving relation to the diesel engine. The flexible coupling has a predetermined spring rate which places the torsional interia of the compressor above a highest predetermined cranking speed and below the predetermined idle speed of the diesel engine. A microprocessor-based electronic controller controls compressor operation. A receiver stores compressed air. A cooling means cools the portable compressed air system. The cooling means has a fan, an intercooler, an oil cooler, an engine radiator, and an aftercooler. The intercooler, the oil cooler, the radiator, and the aftercooler are arranged in two banks, and each bank is defined by two cooling cores juxtaposed one to each other.