The TFT4 measures pressure, temperature and flow up to 4000 times per second and analyses in real time the condition of the fluid in the pipe by a complex real time algorithm. The Flow and pressure measurements close to an engine are influenced by strong pulsations. The said product is equipped with perfectly calibrated sensors. The superposition of compressor, valve lifts, EGR injection etc leads to a complex pressure-flow characteristic, depending on the engine map, the aging and ambient conditions (air pressure, air temperature) and other variables. Since pressure and flow are coupled by the energy conservation (Boyle Mayotte), the correct pressure measurement and mass flow calculation becomes a complex task.