Military ground vehicles are equipped with Automatic Fire Extinguishing Systems (AFES) to protect against enemy threats causing fuel tank ruptures and resulting fuel fires inside military vehicle crew compartments. The fires must be rapidly extinguished without reflash to ensure Soldier protection from burn and toxicity risks. This summary describes the development of a simulation-based acquisition tool which will complement vehicle testing for the optimization of AFES designs for specific vehicles and address their unique clutter characteristics. The simulation-based acquisition tool using Computational Fluid Dynamics (CFD) techniques was validated for an exploratory test box and demonstrated with the evaluation of two different suppressant nozzle configurations for an MRAP vehicle. The result is a cost-savings tool with a negligible development payback period that optimizes Soldier survivability in a fire situation. This modeling tool is currently being applied to predict the effectiveness of crew AFES in a number of Army ground vehicles.