Miles per Gallon, computer seems accurate?

ShiWarrior · 1 Dec 2014 at 21:40

I know we've talked about Miles Per Gallon a million times already

but since changing my car not long ago, I filled it to the brim and tried to go as far as I could before I ran out of fuel (well until the light came on)

could you tell me if my MPG is correct ?

my manual says I have 55 litre tank
I filled it to the brim, and I did 340 miles when the light came on, and it said I still had 50 miles to go, so approx. 400 miles to the tank, computer says around 33 MPG, does that seem accurate to you?

bledd · 1 Dec 2014 at 21:50

The way to work it out manually.

Brim it. Drive until light comes on, Brim it and take note of how much you put back in along with the mileage. Doing it over multiple tanks makes it more accurate

ShiWarrior · 1 Dec 2014 at 21:52

bledd. said:
The way to work it out manually.

Brim it. Drive until light comes on, Brim it and take note of how much you put back in along with the mileage. Doing it over multiple tanks makes it more accurate

ok ill do that for a while ill started it when I fill up again
but for now, what do you think ?

xs2man · 1 Dec 2014 at 22:01

Your tank may well be 55l, but you probably only used 48.2l or something. You won't know exactly unless you brim it again, and take note of the litres you out in and the miles you have covered since last brimming it.

As bledd. Said, repeat over several tanks to increase accuracy. Personally I only ever brim my tanks (it's not like I won't use the fuel), note the mileage, average mpg over the tank and average mph over the tank, and fire that info into fuelly.com.

Obviously I reset one of my obc's at every fill, including the av. Speed and mpg so I can get that data. But after around 17k worth of doing this I have a pretty good idea now. Plus it lets me log every penny spent in running the vehicle.

bledd · 1 Dec 2014 at 22:05

Could be 10L still in the tank, without accurate data, I'd decline to comment.

What car is it?

chanjy · 2 Dec 2014 at 15:39

You should use fuelly.com

kaptainmarc · 3 Dec 2014 at 06:28

Just use an app there's loads of them, just put the data in and it puts it all on a little graph.

dangermouse425 · 3 Dec 2014 at 07:14

I use Fuelly, I've not checked the computer on my Focus, but I don't think it's that far off tbh.

ShiWarrior · 3 Dec 2014 at 07:55

kaptainmarc said:
Just use an app there's loads of them, just put the data in and it puts it all on a little graph.

there are loads of websites about, not sure on apps my phone cant run apps very well

what do you recommend?

Dogbreath · 3 Dec 2014 at 08:16

kaptainmarc said:
Just use an app there's loads of them, just put the data in and it puts it all on a little graph.

You really don't need to use an app, the calculator on a smart phone is more than adequate for working out tank to tank consumption.

Hades · 3 Dec 2014 at 08:36

55 litres = 12.1 gallons

400 miles / 12.1 gallons = 33mpg

kaptainmarc · 3 Dec 2014 at 08:39

Dogbreath said:
You really don't need to use an app, the calculator on a smart phone is more than adequate for working out tank to tank consumption.

The working out is easy yes... but does it collate all the information and store it so you can see the past X amount of tanks and see the variance over a period of time? I think not

Hades · 3 Dec 2014 at 08:44

kaptainmarc said:
The working out is easy yes... but does it collate all the information and store it so you can see the past X amount of tanks and see the variance over a period of time? I think not

Or you could just look at the mpg reading on the dashboard occasionally and decide if mpg if it's getting better or worse.

kaptainmarc · 3 Dec 2014 at 08:53

Hades said:
Or you could just look at the mpg reading on the dashboard occasionally and decide if mpg if it's getting better or worse.

I like graphs though make me moist

bledd · 3 Dec 2014 at 08:57

kaptainmarc said:
I like graphs though make me moist

You'd love my spreadsheet. 5 years worth of fuel logs, alerts me when service items are due and how old each consumable part is

kaptainmarc · 3 Dec 2014 at 09:09

bledd. said:
You'd love my spreadsheet. 5 years worth of fuel logs, alerts me when service items are due and how old each consumable part is

see now that's how you do it! none of this calculator and remembering.

Technology is our friend! You have now given me something to set up tonight :cool:

LupoLover · 3 Dec 2014 at 10:02

bledd. said:
You'd love my spreadsheet. 5 years worth of fuel logs, alerts me when service items are due and how old each consumable part is

I have one like that too!

MissChief · 3 Dec 2014 at 14:58

You're not living dangerously until you put 54.xx litres into your 55 litre tank!

LupoLover · 3 Dec 2014 at 15:54

MissChief said:
You're not living dangerously until you put 54.xx litres into your 55 litre tank!

I can get 40 liters into a 36 liter tank....... You have expansion and pipes to fill! You be amazed the things I have seen people to report doing! (Yes some might not be true)

chanjy · 3 Dec 2014 at 16:04

I put 47l in a supposedly 50l tank the other day. The trip computer told me I only had 5 miles left and I lost my nerve