Turbo charging saves fuel
 

almost all turbo cars run very rich (12:1 AFRs or less) under full boost, which kills your mileage unless you always stay off boost (freeway crusing)

Nissan is supposed to bring a VCR feature.... VCR as Veriable Compression Ratio, not Video Cassette Recorder... :D , in their 2011 Silvia. Nissan said this should help in getting much better gas mileage when boost is not needed.

The Solstice turbo EPA rating is 28 mpg highway and the non-turbo version is 24 mpg highway. IIRC the city rating is 18 mpg for both.

Moderated for content.

turbochargers, if tuned for it, can and most certainly would improve fuel economy while maintaining the same engine output.

unfortunately, designing, developing, and manufacturing a good system is not free. i'm really surprised he didnt say that was the principal drawback. yes, adding a turbo/supercharger will increase complexity and therefore can decrease reliability, but really, that means they need to work harder and longer before they'll get it right--which costs money. and if the prize is not worth the money, automakers won't do it.

turbo for efficiency--i can see it going like this:
salesman: do you want a $25k camry? or would you prefer a $30k turbo camry with lag, roughly the same power output, and +5mpg?
customer: i'll take the cheap one, please. if i wanted to spend $5k for a few mpg, i'd get a hybrid.

The N/A model has a 2.4L engine vs. 2.0 in the turbo, and a shorter 3.91 rear end ratio vs. 3.73 in the turbo. Not a fair comparison.

When comparing a turbo to non-turbo car the turbos will commonly have a longer final drive. The turbo's extra midrange torque allows you to use longer gearing yet still have passing power on the highway. It has been too long since I looked at the thermodynamics but as far as I can tell, turbos don't seem to make gasoline engines much more efficient (diesels are different) but what they let the automaker do is use longer gearing so the engine is turning slower. So in effect, for the same displacement engine you could be turning the motor slower thanks to the extra torque or conversely you have the same torque as a large displacement engine turning at the same speed but lower pumping losses with the little engine. Either way I don't think it is so much an increase in peak efficiency of the motor as an ability to run the motor in a more efficient partial throttle state.

And of course as the article didn't say, that turbo isn't free. Personally I really hate how many of the articles talking about fuel economy enhancing technology don't talk about the cost impacts.

YOu know what would save fuel too....most people dropping some weight off their guts. I could use a drop of 10-15lbs. That would save fuel. Most Americans can stand to lose 20-50 lbs according to some reports. Imagine the collective fuel savings. There should be a fat tax imo.

^ Then you would not be allowed to "Be all you can be"