A multi-phase centrifugal supercharging system (10) configured for supplying compressed induction fluid to an engine (E) is disclosed. The air induction system (10) broadly includes a drive assembly (12) powered by the engine (E), a supercharging assembly (14) driven by the drive assembly (12) to compress induction fluid, and an induction fluid flow control assembly (16) in communication with the supercharging assembly (14) to control operation of the supercharging assembly (14) and cooperating therewith to deliver the compressed induction fluid to the intake manifold (IM) of the engine (E). The supercharging assembly (14) includes a pair of centrifugal superchargers (28 and 30) that are phased by the control assembly (16) between multiple operating phases, including a series phase (172) and a parallel phase (176). An alternative air system (306) is also disclosed, in use with a pneumatic conveyor (300), that phases between normal series operation and parallel, clog-displacing operation.