Aftermarket exhaust parts and the engine. However, the pipes do "ring" with the exhaust pulses and increase underhood noise. Headers can be ceramic coated to reduce the heat radiated in the engine compartment, and to increase the temperature of the pipes which increases the velocity of the exhaust gases. Terminology: Catalytic converters are necessary to reduce emissions but create back pressure due to the exhaust gases being forced through a catalyst, and therefore decrease high-end engine power. Many modern catalytic converters only produce 1-3 psi of back pressure, though this restriction worsens further with use. Hi-flow catalytic converters can replace the standard units
Exhaust brake over the wheels). See also Jake brake. Compression brakes, a form of engine brakes, produce greater noise pollution than exhaust brakes. For this reason, some vehicle original equipment manufacturers prefer to use exhaust brakes despite their lower braking power. Combining compression braking with exhaust braking can increase effectiveness without being as loud as compression brakes. Numerous cities, municipalities, states, and provinces ban the use of unmuffled compression brakes. Most exhaust brakes in the commercial market are protected by patents by companies such as GT Emissions Systems. The butterfly valve made up of acrylic material made in the circular shape, having