Turbo'd engine, mileage better driving hard or easy?

I was mentioning to some guys at work that my dad just got a new turbo volvo
wagon, 5 cyl. I mentioned that my dad is one of the most conservative
drivers on the planet and when he tells me "its got lots of power", he
probably has no idea what kind of power he can really make it produce at
high RPM. It bugs me because I know I could drive the car to its potential.
One of the guys at work, an old timer, says "he won't get good mileage
driving it conservatively". He says you really have to drive the turbo
engines hard to get good mileage out of them. I know turbos do improve
effeciency, but come on, when you are boosting an engine hard you use lots
of gas. I have been looking at getting a new Turbo'd subaru lately, and
this guys advice goes against all I have read. What do you think?

Thanks,
--Dan

 

Talking a lot and knowing a lot don't always go together.

Engine efficiency is a function of engine speed, and auto transmissions
usually keep the engine speed near its optimum. Driving very slow in high
gear may use more fuel. Driving hard wastes fuel.

My S-40 has an auto transmission with a sports mode that makes the engine
stay on low gear longer to boost acceleration. (And it does get the car up
to speed faster.) The manual points out that this will reduce fuel
efficiency.

 

Smooth acceleration, not gunning it, avoiding hitting the redline, shifting
when optimum. This gives you good fuel economy. Drive at a decent and steady
pace and economy will be fine, if you drive the piss out of the car, it WILL
use more fuel.

 

At speed a turbo stuffs more air and the injection will put more fuel
into an engine.
A light foot will get a lot more mileage from the same motor.
Tell the old timer a 4bbl carb does not get better mileage than a 2bbl
if your foot is on the floorboard.