Excel Transmission Calculator
An Article by Bob Hokanson
Preface: Bob Hokanson has prepared a Microsoft Excel Speadsheet for comparing your performance using your selection of gear boxes, transmission gears, rear axle drive gears, and tire diameters. This spread sheet, providing you have the Excel spread sheet program, will allow you to select your potential choices, and actually increase engine speed, and shift gears. It will show you the road speed you will achieve, horsepower permitting.
It is operated by typing in the rear axle gear desired to be evalutated, and the tire diameter to be used. The RPM can be changed, with the arrow keys, to your desired value, and the road speed read out with 4 speed Tiger Mk I Close Ratio, and Mk II Wide Ratio, and four of the five T-5 five speed transmissions. Further information on these transmissions is available in the Dan Walters Performance Tips article.
The "Shft" control can change gears in either direction, and will show you the speed at the selected rpm. Realistically, one should reduce the rpm, from the preveious gears shift point, to match the road speed previously achieved, then the drop in rpm will be indicated, as well as the reaction on increasing speed.
The 4 speed and 5 speed boxes, and rear end choices are independent, and can be evaluated seperately. The tire size effects both.
To down-load this spread sheet to your computer, just click on the link "Transmission Calculator.xls" shown below. ( NOTE: On PC computers use mouse "right-click")