beware VW turbo repair scham 4459

"Not more so than a hybrid car. Turbo doesn't make extra energy, but if you think there's no potential energy in exhaust gbuttes, well, you are wrong."

the power output by compressing the air. But that power increase is not free as you stated, it does come at some cost in milage, just as there is a milage cost from a belt driven supercharger. It takes some energy to spin either kind of compressor. There is no arguing a turbocharger when running results in a net increase in power - one can feel it in seat pants.

A turbo allows an otherwise small modestly powered engine to operate with a wider range of power output. That is what I think truck and car owners are looking for. Most of the time we are not really using an intake compressor (turbo or super), it just provides more of a power reserve that a comparably sized normally aspirated engine does.

One has to be careful in matching compressor enhanced engines to useage though. Strapping a turbo or super charger to a small engine and expecting it to perform at near maximum output can dramatically shorten engine life. At least one of the big motor home manufacturers found this out in the early 1980's then they took a small turbocharged diesel motor and put it in a medium sized motorhome. Those little engines were running close to full output on all but the flats and they were dying after 40,000 miles and their warranty claims went through the roof.

If you don't think that turbos exact some impact on milage just look at the instant mpg readout available on many turbocharged cars. It plummets when you hit the gas, much faster than on the same standard aspirated car. I've tried it on a Volvo S80 in T6 and 2.9 and a Volvo V70 in 2.5T and 2.5 engine configurations.