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
Hush kit Hush kit A hush kit is an aerodynamic device used to help reduce the noise produced by aircraft jet engines. These devices are typically installed on older turbojet and low-bypass turbofan engines, as they are much louder than later high-bypass turbofan engines. Hush kits are used because the engines on jet aircraft generate a large amount of noise, which significantly increases noise pollution near airports. The most common form of hush kit is a multi-lobe exhaust mixer. This device is fitted to the rear of the engine and mixes the jet core's exhaust gases with the surrounding air and a