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
Exhaust system the exhaust pipe often has a hinged metal flap to stop debris, birds and rainwater from falling inside. In a two-stroke engine, such as that used on dirt bikes, a bulge in the exhaust pipe known as an expansion chamber uses the pressure of the exhaust to create a pump that squeezes more air and fuel into the cylinder during the intake stroke. This provides greater power and fuel efficiency. See Kadenacy effect. With an onboard diesel or petrol (gasoline) engine below-decks on marine vessels:- In outboard motors the exhaust system is usually a vertical passage through the engine structure