Improved Mileage via turbo?

[poolguy]

I know this is out of the norm for this forum, but I wanted to see if you guys ever heard of such. One of my subcontractors has a Chevy dually, late model, with a gas big block. We went to lunch in his truck, and I noticed he has a boost gauge on the windshield pod. I couldn't help but ask why, and he said it (turbo) wasn't for the extra power, he said he put it in for the extra mileage! Said he gets 13 to 15 mpg pulling. ***??? Thats a new one on me.
Anybody?

 

[ludakris]

I have only had one gas turbo car, and I always tried to keep it out of boost to get better mpg....

I guess the theory would be you could be getting more power with less throttle if you just got it into the boost....

 

[Mr_Roboto]

Turbo will definitely give better mileage on a diesel, if driven the same. This is because a diesel goes rich to accelerate, and some of that fuel is unused until the air flow (RPM) catches up with the fuel. A turbo helps cut down on that air lag.

I suppose a turbo would help a gasser if it kept them in higher gears and lower RPM's.

 

[Dirtleg]

While driving my wifes H2 in hilly areas I have thought that mileage could be improved if there were more torque down low in the powerband. Sometimes being stuck in a lower gear and 1000 more rpms when just a hair more torque would have prevented the need for a lower gear. Hell, as heavy as that truck is it downshifts on the highway on relatively moderate hills. A small turbo that spooled up really early (<1800 rpm) would probably help economy. It certainly wouldn't hurt.

 

[6 Nebraska IDIs]

Gas vehicles with turbos most definately get better MPG. I have a 97 GST Eclipse that gets between 5-6 MPG more than the non turbo 4G63 engines or the plain 420A engines that come in other Eclipses. And like roboto said, its because of the more power produced, plus its burning a more stoichiometric AFR.
But a diesel would MPG benefit more than a gas.