There are two schools of though regarding optimal efficiency for an exhaust pipe. Some would argue that an exhaust pipe should be short because of its aesthetic appeal. The other school of thought argues that longer tailpipes are better because they provide greater power curves and more overall engine power. There are two pieces of information that you must obtain in order to calculate the proper length of an exhaust pipe for your vehicle.
Determine the center RPM values for your desired power curve. In other words, what will be the RPM amount for your average speed in the car? In general, motorcycles will be between 4000 and 5000. Cars will be between 650 and 800.
Calculate the opening point of the exhaust valve. The opening point is recorded in degrees before bottom dead center (BBDC). The default valve opening for a motorcycle is 43 degrees. The default opening for a car is 90 degrees.
Plug the two values into the exhaust length calculator program from the resources section of this article to get your result.
