Aftermarket exhaust parts 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 Aftermarket exhaust parts are intended to replace the factory fitted exhaust components of a car, motorcycle, or other motor vehicle in order to improve the performance, visual appeal, or sound of the vehicle. Generally, performance enhancements are achieved by reducing the back pressure of the factory exhaust system. Frequently a side effect of a free-flowing exhaust system is either a "different" sound, a higher noise level, or
Steam car steam engine conversions for existing production cars. When air pollution became a significant issue for California in the mid-1960s the state encouraged investigation into the use of steam-powered cars. The fuel crises of the early 1970s prompted further work. None of this resulted in renewed steam car manufacturing. Steam cars remain the domain of enthusiasts, occasional experimentation by manufacturers, and those wishing to establish steam-powered land speed records. In 1967, California established the California Air Resources Board and began to implement legislation to dramatically reduce exhaust emissions. This prompted renewed interest in alternative fuels for motor vehicles and a resurgence