A variable turbocharger apparatus includes a housing, a compressor mounted for rotation in the housing, a turbine mounted for rotation in the housing, a first inlet for enabling air to be conducted to the compressor, an outlet for enabling air from the compressor to be conducted to an engine, a second inlet for enabling exhaust gases from the engine to be conducted to the turbine in order to rotate the turbine, a chamber which surrounds the turbine and which receives the exhaust gases from the second inlet before the exhaust gases are conducted to the turbine, and a bearing assembly for permitting the rotation of the turbine. Fixed vanes are mounted in the chamber which are for accurately directing exhaust gases on to the turbine. A piston is slidable and is positioned between the vanes and the turbine. Control means is connected to the piston and is for controlling the sliding movement of the piston, the piston having an end which is nearest the bearing assembly and which defines a gap, the size of the gap being variable in dependence upon the sliding of the piston under the control of the control means, the size of the gap being effective to control the amount of the exhaust gases that act on the turbine thereby controlling the speed of rotation of the turbine and thereby the amount of air conducted by the compressor through the outlet to the engine. The end of the piston is such that it has a flange which extends radially outwardly and which is provided with slots for receiving the vanes.