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 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, followed by a compressor 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 compressor inlet-adjustment mechanism being movable between an open position and a closed position, the inlet-adjustment mechanism comprising a variable-geometry conical mechanism comprising a plurality of vanes that in the closed position collectively form a frusto-conical inlet member having a trailing edge inner diameter that is smaller than an inner diameter of the shroud surface of the compressor housing at the inducer portion of the compressor wheel such that an effective diameter of the air inlet at the inducer portion is determined by the trailing edge inner diameter of the variable-geometry conical mechanism, the vanes in the open position being pivoted radially outwardly about leading edges of the vanes so as to increase the trailing edge inner diameter of the inlet member and thereby increase the effective diameter of the air inlet at the inducer portion, characterized by: the inlet-adjustment mechanism further comprising a plurality of leading-edge guides mounted respectively at the leading edges of the vanes, and a wire threaded through the leading-edge guides, the vanes pivoting about the wire. 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 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, followed by a compressor 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 compressor inlet-adjustment mechanism being movable between an open position and a closed position, the inlet-adjustment mechanism comprising a variable-geometry conical mechanism comprising a plurality of vanes that in the closed position collectively form a frusto-conical inlet member having a trailing edge inner diameter that is smaller than an inner diameter of the shroud surface of the compressor housing at the inducer portion of the compressor wheel such that an effective diameter of the air inlet at the inducer portion is determined by the trailing edge inner diameter of the variable-geometry conical mechanism, the vanes in the open position being pivoted radially outwardly about leading edges of the vanes so as to increase the trailing edge inner diameter of the inlet member and thereby increase the effective diameter of the air inlet at the inducer portion, characterized by: the inlet-adjustment mechanism further comprising a plurality of leading-edge guides mounted respectively at the leading edges of the vanes, and a wire threaded through the leading-edge guides, the vanes pivoting about the wire. the inlet-adjustment mechanism further comprising a plurality of leading-edge guides mounted respectively at the leading edges of the vanes, and a wire threaded through the leading-edge guides, the vanes pivoting about the wire.