An electrically driven auxiliary blower is usually provided because the turbocharger cannot provide enough air at low engine speeds and loads.

A mechanically driven auxiliary blower is usually provided because the turbocharger cannot provide enough air at high engine speeds and loads.

An electrically driven auxiliary blower is usually provided because the turbocharger cannot provide enough air at high engine speeds and loads.

A mechanically driven auxiliary blower is usually provided because the turbocharger cannot provide enough air at low engine speeds and loads.