Average Port Cross Sectional Area Calculations in Square Inches

The Average CSA of the port can be derived through some simple measurements and basic math. To obtain the Port Centerline Length, measure the port floor from the seat cut to the flange at the port entrance. Write that value down. Measure the port roof using the same start and end points, add that measurement to the floor measurement and divide by two.

Measure the port volume in cc with a burette.

Use the formulas below to calculate the results from the port linear and volumetric measurements. The result will be in square inches.

Average_CSA = Port_Volume_CC / (Port_CenterLine_Length * 16.387)

Port_Volume_CC = Average_CSA * Port_CenterLine_Length * 16.387

Port_CenterLine_Length = Port_Volume_CC / ( Average_CSA *16.387 )

FPS = ( Flow_CFM * 2.4 ) / Average_CSA

Flow_CFM = Average_CSA * FPS * .4166667

Free Download - Velocity Calculations Helper Excel File

This spreadsheet can be used to convert velocity pressures measured by pitot.