Hmmmm , on Octy MkI I managed 630ish on a tank - an average of about 57 mpg.

That was without using the expansion tank.

Now if I'd used it I could have got about 53 litres instead of 50 , and if I'd managed to get 60mpg which was easily possible then that would be 700 miles on the dot.

In Octy II the best I could realistically hope for is about 57 mpg overall , but I do now have a 55 litre tank (+ another 3 litres or so) so I could get 730 miles on a tankfull if I could be bothered to do that many motorway runs driving for economy.

Coming back from Ireland on the M4, i managed 66mpg, for well over half an hour.

on my last trip down to the caravan in st agnes from my home (about 10 miles from Leeds) i reached the "you are now entering cornwall sign" on half a tank, that was loaded up with 4 people 2 dogs a cat and luggage, the buzzer went off a week later on 530 miles but i tend not to use the last 1.75 gallon

OK - I absolutely brimmed my tank (54l) then drove to Derby and back at 70mph on dual carriageways and motorways. I then went to reading this morning (very early on a clear A11/M11/M25/M4 also at 70mph. Result? 690 miles and I bottled it, and put the 10l in from the diesel can in the boot. I then brimmed it again and I reckon I actually used 57l to go 690 miles. That's just shy of 55MPG, which is very possible. I used cruise control this morning and it made a small difference (slightly worse). Running the air-con is catastrophic - almost 8MPG worse according to the display. There is a bit of error in there as I'm not certain in I had 8 or 12 litres in the can. It took 12 to fill it back up though.

Only had my car for three weeks, already done 1500 miles through work. Travelled from the north down to kings lynn, which are mainly 60 mph roads, with plenty of cameras, and managed 61mpg (worked out - rather than relying on comp) got 540 miles out of a tank.

I managed 630 miles confirmed from resetting the mileage counter, drove down to devon & back at an average speed on the motorway of 70 mph, combined average read 68.5 (remapped).

I put 38 litres in the car and it had approximately 50 miles in it left prior to filling.

I regulary get 80-85mpg on my run to and from work. 27 miles round trip. I manage about 460 to a tank. Thats with what weighs about 2 people in the boot. But of course thats just going on the trip comp.

Running the air-con is catastrophic - almost 8MPG worse according to the display

Intresting to see how much difference it actually makes as I leave climate on auto all the time in my octavia. Got about 50 today so that would move up to 58 which is very close to quoted figures.

The best I have had is 650miles between fills from my PD100 Fabia - 69.3mpg which required 42.6 litres to refill which would make it just shy of 700miles range.

I regularly see 800 miles+ range when I go down the A49 to Gloucestershire. I may try my brother's tweak (ric04vrs) for overfilling the tank and see if I can get the magic 1000miles range!

The best I can get out the the car is in the low 80s on the A540 (Wirral) between Heswall and Chester. It must be a ultra low resistance road (if there is such a thing!?) I hit 90mpg @ 60mph and 120mpg+ @ 40mph! It's not even a smooth surface and I wouldn't like to find out how good it is for an emergency stop in the wet...

The average mpg for the life of my car (2 1/2 years) has been just shy of 62mpg over 32k miles and no I'm not a slow driver (I have size 11 toe-tector boots on ,with being a Security Guard, most of the time.)

Philip