This study utilises two modern CFD software packages (ANSYS¯ CFX¯ and ANSYS¯ Fluent¯) to analyse the basic geometric factors affecting the efficiency of a typical impulse turbine injector. A Design of Experiments study is used to look at the impact of four primary nozzle and spear design parameters on the injector losses over a range of inlet pressures. Improved injector designs for both solvers are suggested based on the results and comparisons are made. The results for both CFD tools suggest that steeper injector nozzle and spear angles than current literature describes will reduce the losses by up to 0.6%.