how to made a good torque
L = (850 x ET) / MAX RPM - 3 L = length of exhaust pipe that will be made ET = Exhaust Timing, when the exhaust valve starts to open before the BDP (bottom dead point) MAX RPM = RPM (radians per minute / spin machine) that you wanted to get the peak of power example: My motor starts when the discharge opening 80 degrees before the BDP, then the calculation is L = (850 x 260) / 12,000-3 L = 19.1 inches = 485 mm Then find the calculation for the exhaust pipe diameter required = D = sqrt (CC / ((L + 3) x 25)) x 2.1 D is the diameter of the pipe the desired CC is a cylinder capacity L is the length of the exhaust Then the diameter of the exhaust pipe for my bike is: D = sqrt (171 / ((19.1 + 3) x 25)) x 2.1 D = 29 mm formula above is an excerpt from the book A.A. Graham Bell, the numbers 260 from the number ex plus 180 degree opening Vc = ( pi x (D ²) x S )/ 4 Vc (volume cylinder / CC) pi = 3.14 D = diameter of the bore / piston s = stroke / step on the piston (