MPG calculations

[cully]

how do you guys calculate your mpg?

after a previous thread stated some might be over calculating
the question goes out how do you come to your mpg figure?

i calculate mine ever fill up via one of two methods

method 1
Enter details of fill up into the fuely website
http://www.fuelly.com/driver/cully/306

method 2
take details from recipt, milage reading at fill up and calculate it with pen and paper

56ltrs / 4.5 = 12.4 gallons
476.2miles / 12.4 gallons = 38.4 MPG

   

[sweeney1987]

second method, its most sensical.

Also toms306 is a retard if he thinks you get 0mpg with the car using no fuel and still travelling....
If i knock the car off and travel 3 miles downhill thats 3 free miles, them miles will be infinite but add into rest will give true average mpg reading for tank..

[Dum-Dum]

I use spirit monitor and sometimes check and its always right. I use 4.51 instead of 4.5 for a gallon,

56/4.51 = 12.416851gal
476.2/12.416851 = 38.351109 mpg so already closer to the fueley figure.

[Kezzieboy]

I use spirit monitor too, I do more than enough maths at uni without adding it onto my spare time too

[Jonny81191]

I use the free calculator from Torquecars, also use it to calculate journey costs etc.

[Eeyore]

so im only scraping 40mpg in a hdi estate :/

[ozonehostile]

on a trip to london and back recently the sedan was returning 58mpg average , lucky to get over 30mpg the rest of the time just driving to work

[Dum-Dum]

on a trip to london and back recently the sedan was returning 58mpg average , lucky to get over 30mpg the rest of the time just driving to work

i had over 60mpg out of it once

[ozonehostile]

on a trip to london and back recently the sedan was returning 58mpg average , lucky to get over 30mpg the rest of the time just driving to work

i had over 60mpg out of it once

if i had the patience to drive economically it would be an epic mpg machine, i can last about an hour on the motorway before i get insanely bored and end up having fast lane overtaking sprees haha

[Birk]

£20 gets you about 3gallon, so I just put £20 in and once I've used it, divide the mikes by 3.

[Poodle]

Um, splitting hairs, but 1 gallon is actually 4.546 litres, Chris.

But tbh, even if you got it down as 4.4 or 4.7, you'd still only be about 1mpg out.

[Toms306]

second method, its most sensical.

Also toms306 is a retard if he thinks you get 0mpg with the car using no fuel and still travelling....
If i knock the car off and travel 3 miles downhill thats 3 free miles, them miles will be infinite but add into rest will give true average mpg reading for tank..

Yes I might be a retard, but you aren't doing any miles PER GALLON as you aren't using any gallons, I don't see how thats difficult to understand tbh.

I use the free calculator from Torquecars, also use it to calculate journey costs etc.

I also use this, mainly for the pence per mile feature - MPG on its own is a usueless figure lol.

[fuziduck]

second method, its most sensical.

Also toms306 is a retard if he thinks you get 0mpg with the car using no fuel and still travelling....
If i knock the car off and travel 3 miles downhill thats 3 free miles, them miles will be infinite but add into rest will give true average mpg reading for tank..

Yes I might be a retard, but you aren't doing any miles PER GALLON as you aren't using any gallons, I don't see how thats difficult to understand tbh.

But in terms of travelling you are doing infinite miles from that gallon as you are never using the fuel. That is how the systems work it out in the car.

For example in your case, every time you coast down a hill in gear thus not using fuel the car average MPG would drop towards 0 MPG, which is obviously not true as your MPG will increase if you can conserve fuel whilst coasting in gear.

[Toms306]

second method, its most sensical.

Also toms306 is a retard if he thinks you get 0mpg with the car using no fuel and still travelling....
If i knock the car off and travel 3 miles downhill thats 3 free miles, them miles will be infinite but add into rest will give true average mpg reading for tank..

Yes I might be a retard, but you aren't doing any miles PER GALLON as you aren't using any gallons, I don't see how thats difficult to understand tbh.

But in terms of travelling you are doing infinite miles from that gallon as you are never using the fuel. That is how the systems work it out in the car.

For example in your case, every time you coast down a hill in gear thus not using fuel the car average MPG would drop towards 0 MPG, which is obviously not true as your MPG will increase if you can conserve fuel whilst coasting in gear.

Yeah I know thats how these crap cars work it out - hence my Vaux being so inaccurate. This is why the Golf's system is ideal tbh - it goes to '---' when coasting, so it doesn't knock out the average mpg.

[sweeney1987]

Yes I might be a retard, but you aren't doing any miles PER GALLON as you aren't using any gallons, I don't see how thats difficult to understand tbh.

I dont see how you cant understand that its an infinite number of miles because youre still travelling without using anything!
For it to be 0mpg you need to be stopped in traffic with engine running,
Engine running using no fuel but still using built up momentum is infinite mpg.

Really dont understand why you are trying to complicate this.
if the engine travelled 2 miles and used 0.00000000000000000000000000001 Gallons of fuel what would your mpg be?
Similar story with using 0 gallons

now quit trolling!

[Toms306]

The way you guys are seeing it, if I carry a gallon of fuel in a gerry can for 200miles, I'd have done 200mpg with it. Now surely you can see thats not right!

So whats the difference between it being in a gerry can, or in the cars sealed fuel tank with none getting out?

Sweeny, its not infinite either, it's actually 'nothing'...but expressing that in the form of a number isn't 0 and it isn't infinite, and it certainly isn.t 999mpg.

Do 3 miles at 50 mpg, coast down a hill at apparently 999.9 mpg and the average is then 287mpg.....when its not. Its 50mpg as you can't count something you're not using!

[fuziduck]

Yes I might be a retard, but you aren't doing any miles PER GALLON as you aren't using any gallons, I don't see how thats difficult to understand tbh.

But in terms of travelling you are doing infinite miles from that gallon as you are never using the fuel. That is how the systems work it out in the car.

For example in your case, every time you coast down a hill in gear thus not using fuel the car average MPG would drop towards 0 MPG, which is obviously not true as your MPG will increase if you can conserve fuel whilst coasting in gear.

Yeah I know thats how these crap cars work it out - hence my Vaux being so inaccurate. This is why the Golf's system is ideal tbh - it goes to '---' when coasting, so it doesn't knock out the average mpg.

Tom you are not getting it. The golf MPG calculation will work exactly the same as every other car.

I understand your point that for that particular gallon of fuel you aren't doing any miles. However you have used the previous gallon to build momentum which in turn increases your MPG as you slow down in gear as you are using up the built up momentum.

[Toms306]

Ok, if I'm wrong then fair enough but I'm not gonna get it so might as well just give up there.

[fuziduck]

Ok, if I'm wrong then fair enough but I'm not gonna get it so might as well just give up there.

OK one last ditch attempt at explaining it.

Lets say you have one gallon of fuel. You accelerate and use all of that fuel in one go in which you cover 20 miles. Now by the time your fuel is used up you are doing 100mph, and your momentum allows you to cover another 20miles with no fuel.

From start to finish you have covered 40 miles therefore for that one gallon of fuel it makes 40mpg. Not 20mpg as you would say. You must consider the momentum the car gains.

If you were to brake as soon as you ran out of fuel, the momentum would be turned into heat and then for that gallon of fuel you would only get 20mpg, hence why it is beneficial to not use brakes when aiming for high mpg.

[Ruan]

The way you guys are seeing it, if I carry a gallon of fuel in a gerry can for 200miles, I'd have done 200mpg with it. Now surely you can see thats not right!

So whats the difference between it being in a gerry can, or in the cars sealed fuel tank with none getting out?

Sweeny, its not infinite either, it's actually 'nothing'...but expressing that in the form of a number isn't 0 and it isn't infinite, and it certainly isn.t 999mpg.

Do 3 miles at 50 mpg, coast down a hill at apparently 999.9 mpg and the average is then 287mpg.....when its not. Its 50mpg as you can't count something you're not using!

The joys of mean, modal and median averaging...

If you used median averaging then yes, it'd be skewed. If you used mean averaging, it'd be a bit screwed up.

That's why it uses modal averaging.

[lolsteve]

Driving my to/from uni is 250 give or take a few miles. If I put in £30 of pump diesel (£1.40) then
30/1.4 = 21.42 litres
21.42/4.5 = 4.76 gallons
250/4.76 = 52.52 mpg

Normally I'll use up that £30 of diesel from a mixture of staying at 60 for an hour then 70-80 for the rest of the journey with a car filled with gear

[C.A.R.]

If I get 550+ miles from a tank
Done good

If I get <500 miles from a tank
I probably had more fun...or something is broken.

That's about the limit.

[Jonny b]

If I get 550+ miles from a tank
Done good

If I get <500 miles from a tank
I probably had more fun...or something is broken.

That's about the limit.

Ha ha most I have seen is about 280 lol

[Frosty]

If I get 550+ miles from a tank
Done good

If I get <500 miles from a tank
I probably had more fun...or something is broken.

That's about the limit.

Ha ha most I have seen is about 280 lol

I get about 350 to a tank out of my S16 i think. I never like to fill the tank up though that costs to much at once

[Midnightclub]

Just worked mine out to be 25.3 mpg which is better than I thought tbh

[Jonny b]

If I get 550+ miles from a tank
Done good

If I get <500 miles from a tank
I probably had more fun...or something is broken.

That's about the limit.

Ha ha most I have seen is about 280 lol

I get about 350 to a tank out of my S16 i think. I never like to fill the tank up though that costs to much at once

Your not driving it properly then lol

[Frosty]

Ha ha most I have seen is about 280 lol

I get about 350 to a tank out of my S16 i think. I never like to fill the tank up though that costs to much at once

Your not driving it properly then lol

I can't afford to!!

[Jonny b]

Ha ha oh well bud

[Frosty]

I need the d turbo back on the road for 500/600 miles a tank

[Piggy]

flipping ek...what a lot or arguing over mpg calculus...does it matter?! we each have to put fuel in our own car so stop fussin