Best ways to measure fuel economy??

Fuel economy calculation 101

1. Fill car with fuel
2. Drive car.
3. Re-fuel and record how far you travelled on the last load of fuel
4. Divide litres used by km travelled and multiply by 100

eg. You travel 500 km and use 50 litres (not in a 70 series though LOL).

50/500 x 100 = 10L/100 km

I don't use the km/litre as it isn't the accepted and most used economy method.

No brainer really. If you want anthing more accurate it needs to be done in a lab, etc.

Don't rely on the trip meter, use the speed odometer or better still use the known distance between too towns .

As above but make sure you fill your tank on the same sort of angle as the original fill and also try to do it over a number of trips, Make notes about the conditions, eg headwinds, tail winds up and down hilss etc. Then you'll get a fair average as well as an idea of what you get travelling into a head wind, up and down hills etc

try this web site its very easy
http://www.dropbears.com/u/utilities/fuel_efficiency.html

These days, it's one of those things that you don't want to know.

Same applies for how many litres of water women flush down the toilet every day, and how much of your money governments waste.

the best way to measure fuel economy is to continuously monitor it, ie used fuel vs km's driven, in all conditions.

Doing it once or twice will mean nothing, unless you are doing a long run.

For example ,, I consistently get 9.5 km/lt from our Navara, all local work.
Chuck in a trip up the Hume Freeway to Albury @ 112 km/h and I get 10.5km/lt ( why, ? probably spinning motor easier, suited to vehicle )

Tow our camper, I get 7-8 km/lt, and chuck in a run up into the desert, fully loaded, towing camper, I get 6.5 km/lt

Its all about keeping good records. Simple as that !
Cheers Bucky

Why do people use kilometers per litre, litres per 100k gives you a better undersatnding and is easier to workout.

Regards Richard

Hi Ro,
Short of using sophisticated and therefor expensive flowmeters and distance recording (fifth wheel) gear the easiest way is to fill the tank right up, reset the trip meter and record all fuel used over a reasonable period of time and the total distance travelled. Go back to the same servo and refill the tank right up again.
Then it's just a matter of doing the maths as above.

IMHO once you know what your vehicle does in terms of average fuel economy under most conditions (head/tail winds, fully loaded/empty, towing/not towing) it's not important any more.

Even with the price of diesel at $1.559/litre here, I don't bother worrying about fuel consumption. If I want to go somewhere, I go.
Life is too short for me to worry about the difference between diesel @ $1.35 and $1.559/Litre, or fuel use at 10L/100km and14L/100km when planning a trip.

Just my opinion, whether you agree with me or not is of no consequence to me

Disco.

>Whats the most accurate way?

See my reply to Steve-wots-is-name.

Basically... there isn't one - a dynamometer is a pretty good guide because it's consistent but it cannot calculate wind resistance or traffic (read driver) issues .

For most of us the best way is to average your fuel usage over (say) 50 tanks of fuel.

Mike Harding