https://docs.emtronaustralia.com.au/engine-management/tuning/throttle-mass-flow/tmf-idle-speed-control/index.htmlIntroduction Throttle Mass Flow (TMF) as the name indicates, is the rate at which air mass is flowing through a throttle body in units of grams/second (g/s). The flow through a throttle body is governed by three physical elements: Conversation of mass Newtons second law of motion for fluids Conservation of energy By combining all these elements the ECU can model the flow of fluid through the throttle body accounting for throttle plate thickness and throttle shaft size. One key piece of data is knowing the pressure ratio across the throttle body as shown in the below diagram, the other key piece of data is the current throttle area. If the pressure ratio and throttle area is known, the ECU can very accurately calculate the mass flow rate through a throttle body.Hugoen-us