Interesting one, this. I've been wondering about this myself.

I usually fill up at about just below 3/4 , so it is normally 40 litres, from which I get about 250 miles. Converting this, I make it around 29-31 mpg (I can't work in mpl). An average drive is about 20% traffic jams, 50% Mway @ 85mph, and 30% twisties and A-roads.

Does this sound about right, or should I be expecting more mpg? (12/99)

440km ????????

Once got 480km on a straight Motorway/A-Road run from Heysham to Portsmouth.

Most I have ever had is 420. Now, with winter meaning I effectively only drive in darkness and with the hardtop I am struggling on 26 mpg.

Apparently there are different sized Fuel tanks out there, I can fill mine up to about 42 litres but another guy I know has a 35 litre tank (I think)

Only performance mod is 14 degrees and JR CAI.

I have a big exhaust and KN Drop in filter, otherwise standard.

'91 Roadster with appalling fuel economy for a 1.6 litre car!

I know the feeling :) Funny isn't it, that if you drive like a maniac one week, and like a 70 year old going to church in a Rover the next week, it makes bugger all difference overall. (12/99)

Apparently there are different sized Fuel tanks out there, I can fill mine | up to about 42 litres but another guy I know has a 35 litre tank (I think)

Well, I thought I had a small tank, but then discovered there's a BIG reserve on mine. Most I've put in was 41 liters about 420 kms (last 50 kms fairly nerve wracking, stuck in the Sperrin Mountains on a sunday, and not a petrol station to be seen) Normally on mine, when the gauge first hits the empty mark, I can get in 32-34 liters. Later tanks were 49 liters. (12/99)

Apologies, but I'm the one at Tesco's who holds everyone up by logging everything into the Psion - here's the record of fuel consumption over 2446.6 miles: 34.2, 31.8, 27.5, 28.4, 35.1, 36.5, 34.4, 31.6, 30.8, 37.9, 27.0, 26.8, 29.2, 28.2 - overall 31.1mpg

The mid thirties figures were gentle motorway trips The high twenties figures are genreally in town Autocar gives the tank capacity as 10 gallons or 45 litres - thus if one drives economically and risks running dry one could achieve about 379 miles or 610 kilometres! Even at the average consumption you should still get 311 miles or 500 kilometres. To get as low as 400 kilometres/tank translates to only 24.8mpg. Obviously there's a reserve to allow for, but not that much?

Regarding cold weather, a five year record for my Citroen shows no correlation between low consumption and low temperatures; the possibility exists though that one would drive slower and smoother on wet roads and hence achieve better consumption not worse? (12/99)

I was just about to post on this subject...!

I am lucky to get 400Km out of a tank in my 1990 Auto, and giving it a service has not changed that. My brothers 1991 manual gets him nearly 500Km. He does a mixture of town and motorway and has never fallen below 480Km from a full tank. I'm about to try John Cooksons diagnostic kit on mine to see if it's running on any "default" inputs but would like to increase my mpg by 20% if I can. I thought it was just the crappy auto making the difference, but his has a HKS air filter and performance exhaust. Otherwise they are both standard.

Anyone know what the figures should be ? (12/99)

I seem to be getting about 400km to a tank instead of 440km.

He's complaining???? Those are the sort of kilometers I only get when cruising/touring at 120kph on a very long slab. (12/99)

.. come on .. I have got 300 miles out a turbo'ed car with 100 miles of "fun" on A69 with serious application of throttle (while being within the letter of the law of course :-) .. well dual carriageway speeds for me ... 75/80 mph tops) .. this represents 428 kms .. on the way to Billings.

48 litre tanked 1.8 .. did 298 miles on 44.5 litres .. stopped too early (12/99)

Fuel economy varies from car-car, driver-driver, and drive cycle-cycle. The only way you can compare your fuel econ. is with your previous records. Supermarket fuel, doesn't give you 6mpg less than Esso, as was quoted , sorry, but it's true. Supermarket fuel, used to lack detergents found in more expensive fuels, but this is no longer the case. Only long term use of this, years ago, may result in a dirty fuel track, within the car.

I have an excel chart I made (A very simple one) stored on my homepage, which you are all welcome to use. If you want to document your fuel usage, I suggest you use mine as a guide, and modify it to suit the details you wish to see.

As my fuel econ goes, Mine has been getting gradually worse, this is directly linked to the enjoyment factor :), but I would expect low 30 mpg as a norm. Just add your total mileage, and your litres, and the program will return your mpg, and l/100 kms, for you Europeans . There is a graph on the other sheet that will plot your averages, The excel sheet is here 440 KB http://www.geocities.com/big_air_162/FUEL_ECON.xls (12/99)

Thanks to those who suggested checking the tires....
1 at 17psi
1 at 29 psi (how it went up I'll never know :) )
1 at 23
1 at 28

All pumped up to normal, so let's see if it makes a difference. (12/99)

45 l. (12/99)

I have always thought that it was my driving style (enthusiastic) that has led to relatively high fuel consumption in both MX5's I have owned. The first, a 1.6, I got just under 30 mpg average with a best of 37 on a slowish motorway run and a worst of 26 on dry country roads. *big grin*

My current car, a 1.8 Eunos, I am averaging just under 28 mpg with a best of 35 and a worst of 25.

The most fuel I've managed to get into one tank is just over 45 litres.

If I refuel as the gauge first reads empty it takes around 40 litres.

Economy improves in wet weather due to a compulsory change in driving style! I often decide, after filling the tank, to drive economically to see how many miles I can get out of a tankful. This lasts until the first Volvo/4x4/MPV tries to overtake or until I see an empty windy road in front of me......i.e. about 5 minutes after re-fuelling. (12/99)