Since this came up in another thread, I thought I would start a new one to cover this discussion. The optimum shift points are the rpms at which shifts to the next higher gear result in the maximum amount of horsepower (or torque) being applied at all times. Maximizing horsepower (or torque) at all times while running down the quarter mile for example, will result in minimum elapsed time. To determine the shift points, the best method is to dyno the vehicle in each gear. Then plot all runs on the same plot. You could also just dyno one gear, then calculate for the other gears. The optimum shift point is the rpm at which a shift in to the next higher gear results in horsepower (or torque, you'll get the same result) that is higher than or equal to the horsepower (or torque) in the next higher gear. What this means is that if the curves cross, you shift at the pont where they cross. If they don't cross, you shift at the maximum mechanical rpm limit for the engine.

I have attached an example. It is from a stock single 3rd gear dyno run I found that was done by AEM. I assumed hp was the same in the other 4 gears, with the driveshft rpm being the only difference (obviously). I plotted all on the same chart (5th is not shown because the rpm is too high), hp is plotted against ds rpm. These curves do not cross. Therefore, the optimum shift points will be the maximum safe mechnical rpm limit for the engine. You can use the torque plots, you will get the same answer, physics and the math take care of that for you.