Closing throttle body creates a vacuum in the intake manifold. As spent air and fuel exits the exhaust port, it spins the exhaust turbine wheel which spins the turbo shaft that is connected to the compressor wheel. If there was a long length of exhaust pipe between the engine and the turbo, there would be a time delay between the accelerator being pressed down, the engine speed increasing, and the turbo accelerating. Engine at idle Exhaust manifold Turbine wheel Compressor wheel Air intake To inlet manifold To exhaust system Engine at idle When the engine is idling it does not generate enough exhaust flow to spin the turbo fast enough to produce any real boost. The pressure ratio and corrected mass airflow are the two numbers you need to evaluate the compressor on a map.
Turbocharging for Dummies
The Compressor Big or small? To improve the efficiency, you need to increase the boost to the ragged edge of boost safety. To get the pressure ratio, simply add the amount of boost in psi to standard atmospheric pressure Too small a turbine spools fast but restricts at the top end. A turbocharger is basically a pump driven by the exhaust gases passing out of the exhaust manifold. Intercoolers need to be placed in an airstream while their pipework has to be kept as short as possible.