The present article shows the influence of the measurement method on a transversal section of exhaust system, downstream of the manifold, the dimensional and the acoustics package simulation. For this task the same system section was instrumented with five different configurations; the values of backpressure were measured on maximum power and used as data for the GTPOWER software to make a virtual simulation of acoustics intensity as a function of engine speed. Therefore it was possible to compare the virtual curves with the real measured values of acoustics intensity. Due to the stream lines influence of the analyzed section, we obtained different values of backpressure and curves of acoustics intensity. Finally, it is shown the measured value of backpressure which has the best correlation with the real measurement and identifies the measurement method with piezo ring as the best configuration.