[Tom Vaught]

One more simple calculation, for you, that tells you airflow numbers and how many cubic feet of air mass you would have if you were at sea level and in 70 degree air temp if the carb were flowing 1 pound of air mass in one minute.

Here is the formula:

"A Constant" times Ambient Pressure (Units is Inches of Mercury)

So for example that would be the constant:
1.3562 times 29.921 Inches of Mercury

(29.921 is considered to be the standard pressure at Sea Level conditions)

You come up with 39.66387602

On the bottom of the calculation you have:

A constant (459.67) plus the local Temperature
in degrees F. (We will use 70 degrees Fahrenheit) So 459.67 Plus 70 degrees is 529.67

So then we divide 39.66387602 by 529.67 and we get: 0.074884 pounds per cubic foot of air mass.

If we divide 1 by 0.074884 pounds per cubic foot of air mass we get 13.35398 cubic feet of air mass in that one pound of air at those conditions.

The reality is a typical engine flows between 17 and 19 cfm at idle so slightly more than 1 pound of air mass at idle is going into the engine each minute.

Hope I made the math easy for you to use in the future. Once you get that part of the air equation you can relate it to the fuel calculation in pounds per minute for a given air/fuel ratio.

Tom V.