catalytic converters became mandatory in us in 1975.
catalytic converters became mandatory in us in 1975.
when did catalytic converters become mandatory in us?
1975
the first widespread introduction of catalytic converters was in the united states automobile market. to comply with the u.s. environmental protection agency's stricter regulation of exhaust emissions, most gasoline-powered vehicles starting with the 1975 model year must be equipped with catalytic converters. these "two-way" converters combine oxygen with carbon monoxide (co) and unburned hydrocarbons (hc) to produce carbon dioxide (co) and water (ho). in 1981, two-way catalytic converters were rendered obsolete by "three-way" converters that also reduce oxides of nitrogen (); however, two-way converters are still used for lean-burn engines. this is because three-way-converters require either rich or stoichiometric combustion to successfully reduce .
catalytic converter
free-flowing exhaust systems may maximize peak horsepower by reducing or eliminating back pressure; this is typically accomplished by making the path as straight as possible, using a consistent diameter throughout the system and eliminating obstacles such as catalytic converters and pre-catalytic converters or by replacing the muffler with a less restrictive (and usually louder) one. despite the potential for increased performance by eliminating catalytic converters and other emissions control hardware, doing so will often render the vehicle illegal for street use in many jurisdictions. other aftermarket modifications that bypass the catalytic converters and/or mufflers, such as electric or cable activated exhaust cutouts—which open and reroute the exhaust flow to bypass restrictions in the system—can similarly increase performance, though would likely be illegal in areas where tampering with emissions devices is prohibited, particularly when placed in front of the catalytic converters.
aftermarket exhaust parts