A medium weight polycarbonate (PC) is flame retarded with either a low molecular weight, brominated phosphate ester or a brominated PC oligomer. Rheological characteristics are examined, and advanced CAE software is used to simulate the processability of these materials in automotive applications. The brominated phosphate ester reduces the viscosity of the neat resin, improving both flow and packing characteristics during injection molding. The brominated PC oligomer does not affect the processability of the material. Further examination of molded parts shows that both additives improve tensile properties, although the phosphate ester increases both tensile strength and stiffness more. These results are correlated to the molecular structures of the additives. The reduced viscosity/improved mechanical behavior exhibited by the phosphate ester formulation is also explained in terms of antiplasticization theory.