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Exhaust tunning

Exhaust tunning means by arranging the exhaust pipes with suitable length and suitable
valve timing to exhaust into the same pipe without disturbance.
When the exhaust valve of a diesel engine opens, the cylinder rapidly expands, and gain
velocity and kinetic energy as they pass into the exhaust pipe.
The kinetic energy of the mass of exhaust gas carries it along the exhaust pipe, and causes
a pressure build up ahead of the mass of gas and a partial vacuum behind it. This principle is  used in a tuned exhaust system. The partial vacuum created by exhaust from one cylinder is used to help exhaust expulsion from the following cylinder.
Grouping of exhaust pipes depends upon the firing order, length & diameter of exhaust pipe.

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