An engine system comprising: an exhaust gas system for removing exhaust gas from the engine; a turbocharger comprising a compressor for inducing air towards the engine and a turbine provided along the exhaust gas system and driven by removed exhaust gas for powering the compressor; a hydrogen delivery apparatus adapted to deliver hydrogen to the exhaust gas system such that the hydrogen can combust and expand, thereby increasing the speed of the turbine. The increased speed of the turbine operation decreases turbo lag and increases engine responsiveness.