A turbocharger, comprising: a turbine housing and a turbine wheel mounted in the turbine housing and connected to a rotatable shaft for rotation therewith, the turbine housing receiving exhaust gas and supplying the exhaust gas to the turbine wheel; a centrifugal compressor assembly comprising a compressor housing and a compressor wheel mounted in the compressor housing and connected to the rotatable shaft for rotation therewith, the compressor wheel having blades and defining an inducer portion, the compressor housing defining an air inlet for leading air generally axially into the inducer portion of the compressor wheel, the compressor housing further defining a volute for receiving compressed air discharged generally radially outwardly from the compressor wheel, the air inlet having an inner surface that extends for an axial length along a downstream direction, characterized in that said inner surface is followed by an inlet-adjustment mechanism disposed in the air inlet, followed by a shroud surface that is adjacent to outer tips of the blades of the compressor wheel; the inlet-adjustment mechanism comprising a plurality of vanes constructed of a flexible material, the vanes having leading edges joined to a ring mounted in the air inlet and the vanes being distributed circumferentially about the ring such that the ring and the vanes collectively form a duct, wherein an effective diameter of the air inlet at the inducer portion is determined by a trailing edge inside diameter of the duct, the vanes being movable in a radially outward direction by aerodynamic forces exerted on the vanes by the air flowing to the compressor wheel, the duct having a tapering configuration when the vanes are in a relaxed state such that the trailing edge inside diameter of the duct is smaller than that of the shroud surface, said aerodynamic forces exerted radially outwardly on the vanes causing the vanes to flex generally radially outwardly and increase the trailing edge inside diameter of the duct at the inducer portion, thereby increasing the effective diameter of the air inlet, wherein the inlet-adjustment mechanism is passive such that the vanes are movable in the radially outward direction solely by the aerodynamic forces exerted on the vanes. a turbine housing and a turbine wheel mounted in the turbine housing and connected to a rotatable shaft for rotation therewith, the turbine housing receiving exhaust gas and supplying the exhaust gas to the turbine wheel; a centrifugal compressor assembly comprising a compressor housing and a compressor wheel mounted in the compressor housing and connected to the rotatable shaft for rotation therewith, the compressor wheel having blades and defining an inducer portion, the compressor housing defining an air inlet for leading air generally axially into the inducer portion of the compressor wheel, the compressor housing further defining a volute for receiving compressed air discharged generally radially outwardly from the compressor wheel, the air inlet having an inner surface that extends for an axial length along a downstream direction, characterized in that said inner surface is followed by an inlet-adjustment mechanism disposed in the air inlet, followed by a shroud surface that is adjacent to outer tips of the blades of the compressor wheel; the inlet-adjustment mechanism comprising a plurality of vanes constructed of a flexible material, the vanes having leading edges joined to a ring mounted in the air inlet and the vanes being distributed circumferentially about the ring such that the ring and the vanes collectively form a duct, wherein an effective diameter of the air inlet at the inducer portion is determined by a trailing edge inside diameter of the duct, the vanes being movable in a radially outward direction by aerodynamic forces exerted on the vanes by the air flowing to the compressor wheel, the duct having a tapering configuration when the vanes are in a relaxed state such that the trailing edge inside diameter of the duct is smaller than that of the shroud surface, said aerodynamic forces exerted radially outwardly on the vanes causing the vanes to flex generally radially outwardly and increase the trailing edge inside diameter of the duct at the inducer portion, thereby increasing the effective diameter of the air inlet, wherein the inlet-adjustment mechanism is passive such that the vanes are movable in the radially outward direction solely by the aerodynamic forces exerted on the vanes.