Et prediction and wind conditions – Calculated Industries 8703 User Manual
Page 32
30 — H
OT
R
OD
C
ALC
™
HPc 1.211
Notice that by changing the ME% from 85% to 80% (reducing the
engine’s mechanical efficiency), the corrected HP was reduced
whereas the HPc was increased.
ET Prediction and Wind Conditions
Now let’s say you ran your 3,840-pound 1970 Ford Mustang
Notchback at Top Gun Raceway in Fallon, Nev., where there are
often raging winds. You can use your actual ET and determine
what your ET would have been without the windy conditions. You
will need several new pieces of information. At a minimum, you
need to know what the wind speed and direction were when the ET
was recorded. Additionally, you need to know the race car’s frontal
area and drag coefficient.
To determine your race car’s frontal area, measure the vehicle
from “head-on”, measuring from the bottom of the front bumper to
the 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 race
car’s shape factor, though most are between 80% and 85% of the
race car’s frontal area (excluding dragster style race cars).
Here’s an example of calculating a race car’s frontal area using
a height of 46 inches, a width of 70 inches, and a shape factor of
85%.
KEYSTROKES DISPLAY
ALL CLEArEd
46
IN
3220
IN
2737. S IN
19.006944 S F
The answer is about 19 square feet.