My 2.0HDi gets about 530-540 ish, out of a tank, with some left in there. My granny style driving and daily up and down the A34 help to keep that up, but thought it should be a little better than that. I say granny style, but I cruise at 70. Unfortunately, on the A34 this makes me the slowest on the road, excluding HGV's. Very interested in the use of bio-diesel, might investigate that.