<VV> turbo Corvair fuel mileage

[Ramon Rodriguez III]

Hey guys, just a quick question this time.

If a turbo Corvair is driven very conservatively how bad is the fuel
mileage compared to a N/A Corvair?  Separate answers for highway and local
are preferred.  I have a turbo Corsa I hope to have on the road by the end
of summer, but more likely not till next year and I want to know how
impractical it is going to be to put some miles on it.  I also intend to
buy a Spyder at some point... but right now I have too many Corvairs as it
is.  A couple more Corvairs cornered me and forced me to purchase them late
last year so I'm at seven.  Two of them will be merged into one car, and
two are intended for repair and resale but I'm getting attached to them.
 One needs too much to build but is too decent to junk (excellent
floors/undercarriage)... that one will just be hanging around in case I
ever get to it.

Just for reference I am accustomed to 21+mpg on the highway with my hopped
up 140.  I do know how to drive conservatively.. I think I'd fare alright
on the econo-run with the right car =)

Thanks!

Ray R.