Airflow Calculations

Posted: June 28, 2012 in Induction Systems

An article from Steven P. Duray,

Airflow Calculations:
True Volumetric Efficiency = TVE
TVE = Actual Intake Volume / Engine Displacement
This is often seen as VE = Actual Airflow / Theoretical Airflow on an engine dynamometer.

Turbocharger Compressor Pressure Ratio = PRCOMP
PRCOMP = (Boost + Atmospheric Pressure) / Atmospheric Pressure
NOTE: For every 1000 ft of elevation increase, you lose approximately 1 psi of atmospheric pressure.

Air Density Formula:
Air Density = (2.703)(Absolute Pressure) / (Temp + 460) the answer is in lbs/ft3

Intercooler Air Temp Formula:
TIC out = TCOMP out – (EfficiencyIC)(TCOMP out – TAMB)
NOTE: Typical pressure drop across an intercooler is between 0.5 and 1.5psi. The average intercooler efficiency is usually between 65-70%.

S.P. Duray 20120416

A greatful thank you to Mr. Duray for his contributions.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s