A cutaway view of a muffler showing the interior pipes and chambers.
When the exhaust flow from the engine to the atmosphere is hindered to any degree, back pressure is generated and the efficiency and power of the engine are reduced. Therefore, performance-oriented muffler and exhaust systems use a variety of techniques and methods to attenuate sound to minimize back pressure. For the majority of such systems, however, the general rule of “more power, more noise applies. Several such exhaust systems that utilize various designs and construction methods:
Vector muffler - For larger diesel trucks, using many concentric cones, or for high performance automotive applications, using angled baffles to cause exhaust impulses to cancel each other out.
Spiral baffle muffler - for ordinary cars, uses a spiral-shaped baffle system
Aviation Turbine Muffler - Produces a partial vacuum at carefully spaced time intervals, producing a negative back pressure that effectively "sucks away" the exhaust out of the combustion cylinders