On Jan 26, 10:50 pm, Jim Yanik wrote:
turbocharging uses the wasted energy of the hot exhaust to compress the
intake charge,while supercharging is a parasitic drag all the time.

A turbocharger is also parasitic. It raises the exhaust pressure,
thereby raising the pressure inside each cylinder during the exhaust
stroke. Ain't nuthin' free...

There are two advantages to a turbocharger that I can think of. Fewer
moving parts means less friction (basically one). It can run at higher
speeds that make for more efficient compression.

If any given engine is more fuel efficient with the turbo engaged, it
most likely is only because that engine was designed to run with a
turbo and runs inefficiently without it.

But I could be full of it too.