Abstract: An air-cycle air conditioning system and method, using an automotive turbocharger as the core of the system, was designed and tested. Effects on engine performance were minimized while maximizing the possible cooling possible and also minimizing weight and space requirements. An unmodified automotive turbocharger was tested initially as a baseline in a Reversed-Brayton Cycle air cooling system. A second air-cycle machine, assembled from commercial turbocharger components chosen individually to optimize their performance for cooling purposes, was tested to improve the overall cycle efficiency. An optimized air-cycle air conditioning system was tested on an internal combustion engine to simulate more realistic operating conditions and performance.