Todays engine test bed systems are capable of analyzing only steady state, or slowly varying conditions in an internal combustion engine. For improvement of such combustion engines it is also necessary to analyze the dynamic working conditions. A suitable dynamnic test bed must be capable of simulating the normal road- and vehicle conditions. This paper discusses the relevant requirements and problems. The second part describes the necessary methods of measurement, especially a system appropriate for dynamnic analysis. Resulting from measurements on a spark-ignition engine, (knock-test, varying load and speed) it is shown how valuable dynamic measurements can be.