The aim of the experiment is to observe the exhaust gas flow starting from the exhaust manifold to the catalytic converter at the 4 stroke engine of the passenger car to enhance the system's improvement. The manifold connects each exhaust pipe from the engine cylinders to the catalytic converter. The velocity pattern inside the exhaust manifold is measured using particle image velocimetry (PIV) meanwhile the time series velocity data is measured by Laser Doppler Anemometer (LDA). In the experiment, flow conditions with four pipes working simultaneously or single pipe working independently are tested. The initial velocity condition shown in the next is set at the upstream where the flow is inside the circular pipe. The initial velocity is 28m/s for the all pipes acting and 14m/s for each pipes acting. There are also 3 conditions of measurement: with catalytic converter, without catalytic converter and with hollow catalytic converter. PIV results show the biased flow which is related with the curvature of manifold without catalytic converter condition. When using the catalytic converter or hollow catalytic converter, the velocity distribution becomes same magnitude at whole measurement area. The catalytic converter manages the flow well compared to the other conditions. The difference in the each pipe flow condition is also observed from the PIV results. The difference in the flow is discussed and the frequency analysis of turbulent flow is performed using the time series velocity data by LDA.