Rotational speed, torque, brake power and mechanical efficiency are the factors which govern the performance of the gravitational water vortex turbine (GWVT). In the present study, the effect of different input parameters like flow rate, vortex height, hub diameter, blade position and notch angle have been investigated using various blade shapes and configurations. The results show variation in performance parameters of the runner under different conditions. It is concluded that best results are obtained at maximum vortex height, minimum possible notch angle and minimum possible blade height from the basin bottom. Moreover, the best configuration of blades is the straight blades fixed at an angle on the least possible diameter of the hub.