Calculated Industries Hot Rod Calc 8703 User Manual

Contents

30 — HOT ROD CALC ™ HPc 1.211Notice that by changing the ME% from 85% to 80% (reducing theengine’s mechanical efficiency), the corrected HP was reducedwhereas the HPc was increased.ET Prediction and Wind ConditionsNow let’s say you ran your 3,840-pound 1970 Ford MustangNotchback at Top Gun Raceway in Fallon, Nev., where there areoften raging winds. You can use your actual ET and determinewhat your ET would have been without the windy conditions. Youwill need several new pieces of information. At a minimum, youneed to know what the wind speed and direction were when the ETwas recorded. Additionally, you need to know the race car’s frontalarea and drag coefficient.To determine your race car’s frontal area, measure the vehiclefrom “head-on”, measuring from the bottom of the front bumper tothe top of the roof and the widest point to point of the race car (e.g.door handle to door handle). It is also helpful if you know your racecar’s shape factor, though most are between 80% and 85% of therace car’s frontal area (excluding dragster style race cars).Here’s an example of calculating a race car’s frontal area usinga height of 46 inches, a width of 70 inches, and a shape factor of85%.KEYSTROKES DISPLAY ALL CLEArEd   46 IN    3220 IN    2737. S IN  19.006944 S FThe answer is about 19 square feet.