The performance of an Al alloy component when tested under dynamic conditions is defined on the basis of the amount of the absorbed energy during impact and the dampening rate of the striker. These tests can be complex and costly, and sometimes difficult to be realized for some specific components. An useful and “ideal” approach could be the use of numerical simulation tools for virtually testing, but this objective actually remains an ambitious approach, since it requires a deep research of the factors that determine the elasto-plastic material behavior up to fracture. Even more difficult is the characterization of the material in the case of Al alloy diecastings, where the mechanical properties strongly depend on casting defects.By linking mechanical results with numerical simulation data of filling and solidification, a through-process model is developed to predict the defects’ location and amount, thus the structural behavior of die cast components. Furthermore, with particular reference to one demonstrator component, an high pressure die cast steering housing, the innovative correlation between defects (e.g. air inclusion, shrinkage porosity etc.) and mechanical properties has been implemented in MAGMASOFT® simulation tool in order to transfer the realistic local ultimate tensile strength to LS-Dyna FEM code. The multi-objective optimization strategy has been applied to minimize the air entrapment and maximize the local mechanical properties of Al alloy. The final full integrated, and more realistic, approach permits to estimate the single effect of proper Al diecasting design, remaining defects and residual stress on the absorbed energy under impact condition.