For the new generation injector a Design For Six Sigma (DFSS) project has been started in the early stage of the project. The DICOV (Design, Identify, Characterize, Optimize, Validate) methodology has been used for the project chart. The project has been dived in subsystems and, for each, a DFSS subproject has been carried on. One of this subsystems is the injector seat. With the FEM models the Optimize phase has been analyzed using the DOE methodology. The designed workflow involve a Creo 2 parametric CAD model, a Matlab script and a ANSYS Classic solver. Everything is driven by ModeFrontier. A first screening DOE with 15 design dimensions is performed and the 7 main factors have been found. A subsequent Full factorial DOE on the main factors has been run and with the results the Transfer function has been found. The Capability analysis on the LSL (Lower Specification Limit) using the Montecarlo analysis has been performed and design has been verified.