An aftercooler is provided comprising a housing, an outlet diverter coupled to the housing and having an outlet port, and an inlet diffuser comprising a forward wall having a peripheral rim coupled to the housing, an upper wall connected to the forward wall, a lower wall connected to the forward wall, a first side wall connected to the upper wall and the lower wall and having a first end disposed adjacent the peripheral rim and a second end disposed adjacent an inlet port of the inlet diffuser, a second side wall connected to the upper wall and the lower wall and having a first end disposed adjacent the peripheral rim and a second end disposed adjacent the inlet port, and a plurality of fins disposed within an interior volume of the inlet diffuser collectively distributing air across an outlet opening of the inlet diffuser for delivery to the housing.