Calculating an engine's camshaft requirements
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| − | Yes, there is and has been an equation that calculates an engine's camshaft requirement, with an accuracy of +/- 1%. You may not believe it, but it is true and it doesn't require a college degree to understand. It was written in 1977 by, the late, Dick Jones, former Technical Racing Manager for Champion Spark Plug Company, in charge of their West Coast Engine Dyno Facility. His formulas have been used by many of the industries premiere engine builders, aftermarket parts manufacturers and two or three cam companies. The math has been qualified as a true equation by two separate college professors, and verified by a | + | Yes, there is and has been an equation that calculates an engine's camshaft requirement, with an accuracy of +/- 1%. You may not believe it, but it is true and it doesn't require a college degree to understand. It was written in 1977 by, the late, Dick Jones, former Technical Racing Manager for Champion Spark Plug Company, in charge of their West Coast Engine Dyno Facility. His formulas have been used by many of the industries premiere engine builders, aftermarket parts manufacturers and two or three cam companies. The math has been qualified as a true equation by two separate college professors, and verified by an automotive engineer with a PhD in Fluid Mechanics/Dynamics. |
| + | Most everyone in the camshaft business has known about the equation, or formulas, for at least 25 years. But, only a few took the time to try it out and have been using it ever since. The Jones Equation is built on, and describes, the mathematical relationships of the engine parameters, operating variables and performance. The equation can solve for, or be solved by, any of the related parameters, including the camshaft. | ||
| + | The Jones Equation calculates the valve opening lift curve, required by the effective port area, to fill the given cylinder the desired V.E.%, at the requested RPM. | ||
| − | + | Here are the basic intake principals of the equation: | |
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| + | • Design for 300 FPS Mean Port Velocity (up to 4500FPM piston velocity). | ||
| + | • Design Velocity increases above 4500 FPM Piston Velocity. | ||
| + | • The bore and the stroke dictate the cylinder volume. | ||
| + | • The rate of volume is dictated by the cylinder volume and RPM at Maximum HP. | ||
| + | • The required port area is determined by the rate of volume demanded by the cylinder at the mean port velocity. | ||
| + | • The available air to supply the cylinder is determined by intake port flow CFM. | ||
| + | • The effective port area is calculated from the available intake port flow CFM. | ||
| + | • The relationship between the port area required and the effective port area determines the net intake valve lift. | ||
| + | • The relationship between the Mean Piston Velocity in FPM and the Mean Port Velocity in FPM dictates the req. intake valve seat duration. | ||
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| + | If you're having a hard time believing it works, that's understandable. If you don't want it to work, you're not alone. | ||
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| + | Here is a quote from one of the buick engineers, in charge of the indy v6 engine program years ago. "We don't agree with Dick's numbers or method, but we still need him to design our camshafts." | ||
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