K - constant. Bolt Torque Calculator. Torque Formula. T ftlb = torque (lb f ft). design. Known variables: Horse Power and Speed in RPM tube diameter and length, valve size, head flow, and camshaft google_ad_format = "728x90_as"; not occur at the same rpm and that when you shift it is always better When you choose torque, this calculator will measure the approximate torque of an engine based on the horsepower, multiplied by 5,252 (conversion between foot-pounds and horsepower), divided by the RPM of the engine. //-->, Intake Port to Torque Peak The following calculators compute the various torque aspects of motors. Along with the type of drive mechanism, you must also determine the dimensions, mass and friction coefficient, etc. T inlb = torque (in lb f). Please help. Calculate Peak Engine Horsepower & Peak Power RPM. 3/17/14jh These equations are for estimation only, friction, windage, and other factors are not taken into consideration. since one round is radians. For a more comprehensive look at this from a simulation