i just drove to and from port macquarie (from sydney) the past week
the trip up is about 350-400km, i used a little over half a tank, thats with air con on, and my system pumping most of the way
relatively smooth trip up with speed limit of 110 most of the way, however there was a bit where it was variable and came down to 60 for awhile
i had a nice fang too...brought it up to 160 then chickened out
already pending a license suspension so decided not to risk it anymore