Additional numerical simulations were performed varying maximum voltage acting on the stack (up to +30%) and the injector characteristics predicted at the different voltage levels were compared. The optimum maximum voltage was approximately identified as the minimum value that can guarantee the full lift of the stack at the maximum rail pressure: this was made in order to avoid voltage over dimensioning. The newly designed injector was set up and tested on the hydraulic rig. Its performance was in line with the model predictions and the stack was able to reach the design value of the maximum lift, that is 0.65DLps, in all the working conditions (pnom 6 pref). However, the simulation results showed that the needle could not reach the stroke-end at pnom P 0.9pref. The reduction of the needle lift at very high pnom values was mainly ascribed to the deformation of the lever-amplifier: a solution to the problem can be to stiffen the lever-amplifier.