1) Muffler attachment 2) Pollution belcher 
(from the article `emission-control system`) ...to limit the discharge of noxious gases from the internal-combustion engine. There are four main sources of these gases: the engine exhaust, the ...
[n] - a pipe through which burned gases travel from the exhaust manifold to the muffler
noun a pipe through which burned gases travel from the exhaust manifold to the muffler