Exhaust system Law in the United States and other countries to not have a catalytic converter. Converters may not be removed from a vehicle that is used only for "off-road" driving in the United States. The main purpose of a catalytic converter on an automobile is to reduce harmful emissions of hydrocarbons, carbon monoxide and nitrogen oxides into the atmosphere. They work by transforming the polluted exhaust components into water and carbon dioxide. Cat-back (also cat back and catback) refers to the portion of the exhaust system from the outlet of the catalytic converter to the final vent to open air. This
Exhaust system all or most of the exhaust system is visible and may be chrome plated as a display feature. Aftermarket exhausts may be made from steel, aluminium, titanium, or carbon fiber. Motorcycle exhausts come in many varieties depending on the type of engine and its intended use. A twin cylinder may flow its exhaust into separate exhaust sections, such as seen in the Kawasaki EX250 (also known as the Ninja 250 in the US, or the GPX 250). Or, they may flow into a single exhaust section known as a two-into-one (2-1). Larger engines that come with 4 cylinders, such as