# Air Flow Rate

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

## air flow rate formula

$$\large{ CFM = \frac {CID \; RPM \; VE} {3456} }$$
Symbol English Metric
$$\large{ CFM }$$ = cubic feet per minute $$\large{\frac{ft^3}{min}}$$ $$\large{\frac{m^3}{s}}$$
$$\large{ CID }$$ = cubic inch displacement $$\large{in^3}$$ $$\large{mm^3}$$
$$\large{ RPM }$$ = engine speed $$\large{\frac{r}{min}}$$

$$\large{\frac{r}{min}}$$

$$\large{ VE }$$ = volumetric efficiency $$\large{dimensionless}$$