mpg

hmc

hello
can someone give me a rough calculation please
i have a new car and wondered how it was doing
it is diesel
approx £35 in tank
done approx 290 miles and not on the red line just yet

thankyou

BillScarab

As we don't know how much the fuel cost and how much wsas in the tank when you put the £35 in how can anyone give you a figure?

It's not hard to do yourself you know. Brim the tank and rest the trip to 0. Driver for a week or two and then brim the tank. Make a note of how many litres you put in and what the mil;eage figure is on the trip then you can calculate the mpg.

Or if it is a new car just look at the computer? Most cars nowadays seem to have them.

BTW a gallon is 4.54 litres.

Lemonade_Pockets

About 38mpg. But that is assuming two things
a) the price of fuel was £1 a litre
b) the tank was empty when you filled up and is empty again now.

If the fuel was cheaper MPG goes down a fraction
If you have more fuel left than there was when you filled it up then MPG is slightly higher.

And just to be pedantic a gallon is 4.55 litres

hmc

thankyou
i need to work it out better then as 38 is rubbish when i was told it would do around 60 to a gallon
sorry to not have given you details im no good at this sort of thing lol
trouble is i darnt go too low as i dont know what is empty for this car lol

Lemonade_Pockets

Best way to do it is.

1)Fill the car up to the top.
2) Reset the trip meter
3) Drive around untill its as low as you dare
4) Refill. Make a note of the litres required to do this and the mileage you have done

5) Do the following calulation:
Litres divided by 4.55. (tells you how much fuel u have put in, in gallons)
Then divide the mileage you have done by the gallons.
This will give you MPG.

E.g I've done 400miles since my last fill up and its just taken 36.4 litres to refill.

36.4/4.55 = 8 Gallons

400miles / 8 Gallons = 50 MPG

AdrianHi

OK, common situation this one on motoring forms, people attempting to determine their mpg on how much a tank costs and how close to the red line they are.
It's a nonesense way to measure it and to do it properly you don't need to run the tank dry. Fill up at the quarter tank marque if you want to.
Here is the method:

1. Fill up your tank and make a note of current mileage.
2. Fill up again, oh say around the 1/4 tank mark
3. Make a note of how much fuel you put in.
4. Make a nots of current mileage now.

Mileage at 4. = Mileage at 1. = Miles covered on the fuel used noted at 3.
Divided litres by 4.55 (close enough) for gallons.
Divided Miles covers by gallons and you have your MPG over the distance covered.

You don't have to work it out each time you fill up, so long as you keep a running total of fuel your putting in you can fill up many times and then do the calculation, which will give you an even more accurate result.

AdrianHi

Lemon Pockets types faster than me :rotfl:

hmc

thankyou, i never look at how many litres goes in just how much it costs lol

i have written down your instructions lol

so if its doing 1/2 the mpg it should be doing what could it be thats wrong?
another daft question i know

Lemonade_Pockets

Lol great minds

If its a new car they sometimes take a while to "run in" every new car i've had has taken at least a couple of 1000 miles before its returning reasonable MPG. Some diesels i've had only run a lot better after their first service.

It could be your driving.

Thirdyly MFR quoted figures are notoriously hard to attain in real world driving. They conducted in a lab which is supposed to simulate real world driving, but sadly never do. There only real use is to compare cars against each other.
You should be able to acheive the combined MPG if you don't do too much stop start driving round town.

hmc

thanks
no its not a new car
im not a hard driver
lol
ive had it 3 weeks so just finding my way round
1.5 clio diesel

Lemonade_Pockets

Should be able to get 50 on a run easy out of that. Do you know if its the 65bhp or the 80? The 80 is slightly better on juice but should still be able to crack 50 with ease on the 65.

Try keep the engine in the sweet spot which if iirc should be about 1900rpm anything below this may cause the engine to labour and use more juice. Also if you haven't had a diesel before there is no point reving it much past 2500 and hardly any point at all at going past 3. Which means lots of gear changes

Otherwise see if its due a service. The service intrevals are extremely long so it might not of been done for some time.