Did you try a Google Image search? A quick search revealed this gasoline turbo BSFC map:
via:
Turbo and BSFC - CleanMPG Forums
Not particularly helpful without seeing the comparable non-turbo though.
In that vein, I also saw the map for the naturally aspirated version of your 1.4L engine on the gm-volt forum:
http://gm-volt.com/forum/showthread....let-Volt/page7