Answer: Your exhaust system is responsible for converting your engine’s harmful emissions into less harmful substances. It is also in charge of transporting your vehicle’s emissions through the exhaust system and out the tail pipe. An exhaust down pipe is the piece of pipe that connects the exhaust manifold, which collects and funnels all of the engine’s gases into the rest of the exhaust system, and the catalytic converter, which converts the engine’s harmful gases into less harmful substances. Down pipes are specifically designed with a large diameter so the engine’s gases can travel quickly through the exhaust system without any restrictions.