WHY DO CARS NEED A CATALYTIC CONVERTER.

A catalytic converter’s primary function is not to “burn off excess fuel”.

Courtesy UTI:

A catalytic converter uses a chamber called a catalyst to change the harmful compounds from an engine’s emissions into safe gases, like steam. It works to split up the unsafe molecules in the gases that a car produces before they get released into the air.

Gases are brought in from the “input” pipe connected to the engine of a vehicle. These are blown over the catalyst, which causes a chemical reaction that breaks apart the pollutants. The less-harmful gases now travel through the second pipe, or the “output,” that is connected to a car’s tailpipe.Learn more

So, hydrocarbons, carbon monoxide and oxides of nitrogen in = water, carbon dioxide and nitrogen out.