Air compression from the turbo adds considerable heat to the charge air, robbing the engine of the turbo’s full horsepower potential. Intercooling reduces the intake temperature and the charge air density, thereby enhancing the performance of the turbo. Conventional air intercoolers waste the heat of compression to the atmosphere. A water injected intercooler cools the charge, humidifies the air and reduces the combustion chamber temperature. The lower combustion temperature reduces the tendency for knocking and allows higher boost pressures. Finally, water injection lowers the NOx emission from the engine.