Is it normal ?

[amv8beauty]

Hi all,

drove about 8-11 miles and the vantage drunk about £12-£15 worth of petrol.

the counter argument would be it's the way i drive however i dont drive hard or fast i tend to just cruise

any help would be appreciated

[michael gould]

amv8beauty said:

Hi all,

drove about 8-11 miles and the vantage drunk about £12-£15 worth of petrol.

the counter argument would be it's the way i drive however i dont drive hard or fast i tend to just cruise

any help would be appreciated

no its not normal !!!! .....according to your figures your getting 3-5 MPG.......i suggest your figures are wrong or you have a big hole in your petrol tank

[Adam2S]

No its not normal at all, but over such short distances the variances of squeezing in an extra two or three pound into the tank are significant to the calculations.

How did you control the filling up before and after to ensure you accurately assessed how much fuel the car used?

[Shmee]

amv8beauty said:

Hi all,

drove about 8-11 miles and the vantage drunk about £12-£15 worth of petrol.

the counter argument would be it's the way i drive however i dont drive hard or fast i tend to just cruise

any help would be appreciated

Around London if you are driving gently you'll get about 10-11mpg at best (or that's what I do when it's city mileage in traffic), but I would guess that there is some variance in the amount that's going in too, perhaps measure an entire tank and calculate it. Fill it up to full and reset the trip then when you next fill up you can see exactly how much fuel has gone back in to cover the previous mileage and therefore can work out the economy using an online calculator like this one: http://www.hypermiler.co.uk/mpg-calculator

[Ice27]

What does the on-board trip computer say?

Mine says I'm averaging 17.6 mpg, which seems pretty accurate.

[amv8beauty]

i put it in just over £30 this morning and it stated that it had 150 miles left that end of journey said i had about 95miles left it was half way then dropped quite alot.to the middle between empty and half way

[lady topaz]

Just did some rough calculations and my to and fro work consumption in heavy traffic results in around 13/14mpg. On a run without giving it too many beans I can get double that. Sticking to the NSL of course

And thats in a very greedy V12

So either your calculation is way off, you drive like a maniac, you have faulty guages or a fuel leak.

[brianjone5]

The margin of error in calculating mpg in a run as short as 8 miles, filling up from a gas pump, is huge.

Best way is to fill tank until shut-off (no topping off), do the run you want to measure: drive like a pussy on empty roads for good numbers, drive like hell for less good numbers.

Refill at the same pump, until same shut-off. Then calculate.

[DAMIT]

All the cars I have driven over the last few years only do about 4-5mpg for the first few miles from cold, according to the computer read outs.

It is my understanding that the engine has to run "rich" to get the Cats get up to temperture and working. Result= Very poor MPG for first 10 miles or so.

[amv8jd]

Ice27 said:

What does the on-board trip computer say?

Mine says I'm averaging 17.6 mpg, which seems pretty accurate.

I admire your restraint sir!

I'm currently averaging 16.1 mpg and thats on it's way back up, mixture of country roads, dual carriage way / motorway and attempting to get back to the future

amv8beauty said:

i put it in just over £30 this morning and it stated that it had 150 miles left that end of journey said i had about 95miles left it was half way then dropped quite alot.to the middle between empty and half way

The distance computer isnt the best / most accurate way of determining fuel used as it uses a mixture of the previous miles driving etc to work it out so the way you drive can vary the distance available greatly, I've gone from 350Miles to 75 Miles in a matter of a few miles, best thing to do is reset one of your trips when you tank up and see what mpg you get.

Then it's an easy calculation
F = cost of fuel per liter
Gc = Gallon Cost
Mpg = Milees per gallon
Cpm = Cost per mile

F * 4.54 = Gc / Mpg = Cpm

So from that at 140.9 pre liter and 16 mpg
140.9 * 4.54 = 639.68 / 16 = 39.98 so thats nearly 40p a mile

Edited by amv8jd on Wednesday 27th April 18:25