Jan Przewlocki provides a deep insight into the post-oxidation processes in an exhaust manifold of an SI engine. Besides the evaluation of 3D-CFD simulation results, tools are developed to evaluate them in a target-oriented way. In addition, a 1D post-oxidation simulation model was developed that is capable of reliably predicting post-oxidation effects within the exhaust manifold. This study shows the development process of the 1D model approach and elaborates its strengths and weaknesses.