Designers are under increasing pressure to provide powertrain systems which meet tougher market and legislative requirements for:- performance, emissions and economy reliability and durability noise and refinement To meet increasing competition, powertrain products need to be “fast to market and right first time”. This implies the evolution of existing technology, comprising multicylinder reciprocating engines and gear transmissions, drawing on a database of decades of powerplant design experience.It is with this background that CAE has proven engineering value supporting key areas of powertrain engineering to meet these technological challenges in a cost effective and timely manner.This paper follows the analytical engineering of a typical component, the exhaust system. Particular emphasis is given to the manifold and downpipe components which duct gas from the cylinder head to the catalyst. The compromises relating to engine performance, structural integrity, noise and vibration and catalyst warming are described and the analysis tools available are demonstrated. Particular emphasis is placed upon the integration of software packages. These are illustrated through the use of a case study which assesses the majority of designs currently considered for four cylinder automotive gasoline engines. Where appropriate, validation of the analysis tools for thermal performance under steady state and dynamic engine operation is provided.