Miles left in tank.......

[shanemorgan]

Good morning guys.
I have been monitoring my counters on my car for a little while now just to get a rough idea of what it is doing MPG and stuff.
I have had the car now for 3 weeks and i have noticed something (maybe nothing). The first week i had the car i reset the counters and then went about my normal activities my average daily travel to and from work is 15 miles each way. In the first week i got the MPG upto 40.5 and from what i could gather on the miles left in the tank it was reducing by about 12-13 miles each way. Nothing has changed but now this week it has been 40.1 MPG (over 700 miles) and it is taking 21 miles off the miles left in tank each way, so my to and from is according to satnav 31 miles from start to finish but on the miles left in tank it is taking 43 miles off the counter and (it maybe my imagination) the petrol gauge seems to be going down quicker.
i drive this car like my nan would just to get the best economey out of it and am puzzeled to why it has now changed so much i take the same route, drive exactly the same, just cant figure it out. It maybe nothing but thought i would ask and see whats the word from the Pro's on the site.

All the best
Thanks in advance
Shane

 

[*Badger*]

Its a french inaccurate computer. The only true way to calculate MPG is to brim your car, run it till the light comes on and fill it up again, keep a copy of your reciept and then work your MPG out manually.

Some computers are more accurate than others, my 172 was rubbish and would regularly see 45+mpg, where as my 182 seems much more accurate (and is within 1 or 2 mpg when I work it out manually).

 

[Goodj]

The computer takes wild guesses at range. MPG's may be more accurate but range will be along the lines of

Current amount of gallons in tank * miles per gallon = range
or
vague * Vague = vague squared.

Once you get past the 1/2 tank mark on the dial, you'll find rane estimates start to swiftly drop

 

[mark123]

After brimming mine (11 gallon tank) I've run out when the computer says I've only used 9.9 gallons.

 

[Goodj]

Perfect example! ^^^^^

 

[shanemorgan]

Cheers Guys

Thanks for the feedback all taken onboard.
Bassically ignore all of what it says coz its prob wrong
I will do the fill it up (on pay day) test and see what i work it out as from there.

All the best
Shane

 

[Silent_Scone]

Computer dit non

 

[Goodj]

On a side note.
Given that a speedo reads over by about 5/10%, does this mean our mileage is a percentage over too?

 

[shanemorgan]

On a side note.
Given that a speedo reads over by about 5/10%, does this mean our mileage is a percentage over too?

Interesting to know the answer to..

Shane

 

[Taleski]

so how big is the fuel tank on the 182? when i fill up i usually have 100kms (60miles) left on the trip computer and manage to fill up 35 litres (9ish gallons).

edit: i always assumed it was 50litres?

 

[shanemorgan]

so how big is the fuel tank on the 182? when i fill up i usually have 100kms (60miles) left on the trip computer and manage to fill up 35 litres (9ish gallons).

edit: i always assumed it was 50litres?

Hey there Taleski

Something i would not know the answer to sorry maybe someone reading this will come in and help us find the answer.

All the best
Shane

 

[Taleski]

bump!