The exhaust manifold collects exhaust gas from the cylinders in a multiple-cylinder engine. Generally, the exhaust manifold is incorporated into the engine, so it is sometimes not included in the exhaust system. However, the exhaust manifold greatly affects the engine output and the sound output of the exhaust system, so it should not be omitted from the exhaust system.

The manifold converter is an exhaust gas purification device that transforms toxic components in the exhaust gas, such as HC, CO and NOx, into harmless substances through catalysis and removes them. For cars whose engines have relatively small displacements, the converter is connected directly to the exhaust manifold, instead of being installed in the conventional under-the-floor position. A pre-converter or a sub-converter may be installed in front of the converter.