Wow, I didn't realize there was such a discrepancy in fuel tank capacity! I know on my 97 with the 45-liter (11.9 gallon) tank, the fuel light comes on once you've used up about 10.8 gallons, and in face you can't even get the car to start up if it's parked on an uphill incline when it's that low. The lowest I've run mine was about 20 miles past the low fuel light and it took 11.25 gallons to top it off. I guess I had always assumed that would mean the Civic must be pretty accurate as far as holding the stated capacity.

I posted over there asking if they topped off any of the cars afterwards. Certainly if the Civic used up 15 gallons to go 1022km, that would have been more like 42mpg. If it was 16 gallons from topped off to bone dry, that's only 39.5mpg. Those are actually much more in line with the rated figures. As for what I could have done.. I dunno, it's tough to say. I've been impressing myself more every day with how much my own FE has improved by implementing as many of the hypermiling techniques as I can. My last tank was 43.1mpg, and that's in the heat of summer with all suburban driving! I think that once we hit the fall's sweet spot of 60-75 degree days, I'll easily do 45mpg commuting and may make an attempt at 50mpg for a long highway trip.