How do you correctly work out your LPG MPG v Petrol ?

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Tecnobaz
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How do you correctly work out your LPG MPG v Petrol ?

#1 Post by Tecnobaz » Sat May 21, 2011 7:04 pm

My outlander runs at 21MPG on petrol.
The last fill on LPG was 36l @83.9p per litre.

So thats £30.20 LPG and I covered 168 miles.

Now I'm lost as maths is not my strong point.

Can anybody work this out for me please.

Barry

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Re: How do you correctly work out your LPG MPG v Petrol ?

#2 Post by richard_ha » Sat May 21, 2011 7:23 pm

36 * 0.22 = 7.92 gallons

168/7.92 = 21.2 mpg
http://www.FillLPG.co.uk and http://www.FillMeWithLPG.co.uk - Your LPG Filling Station Directory

Tecnobaz
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Re: How do you correctly work out your LPG MPG v Petrol ?

#3 Post by Tecnobaz » Sat May 21, 2011 7:51 pm

Does that mean on petrol price (139.9) vs lpg price (83.9) that the overall MPG is around 32ish?

If thats right its not quite the saving I was after but then again when I last had an LPG car I was only paying 42p

I have a flogas dept about 10 miles away but thats in the wrong direction for work, the LPG there is only 74p I'm thinking that by the time I've done the 20mile round trip to fill up, I'm no better off than paying the 83.9 which is on route to work.

Barry

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Re: How do you correctly work out your LPG MPG v Petrol ?

#4 Post by richard_ha » Sat May 21, 2011 8:18 pm

I make it 35mpg equivelant.
http://www.FillLPG.co.uk and http://www.FillMeWithLPG.co.uk - Your LPG Filling Station Directory

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Re: How do you correctly work out your LPG MPG v Petrol ?

#5 Post by rossko » Sat May 21, 2011 10:31 pm

Tecnobaz wrote: by the time I've done the 20mile round trip to fill up, I'm no better off than paying the 83.9 which is on route to work.
20 miles at 4.67 miles per ltre LPG = 4.28 litres, cost £3.16 to get there and back

Savings on a 36L fill at 74p instead of 83.9 = £3.56, without valuing your travel time.

If you don't judge it to get there just as the tank runs dry, for example
savings on a 30L topup at 74p instead of 83.9 = £2.97

If you misjudge it and burn 1 litre of petrol to get the last five miles after the LPG tank dries, it costs about £3.80 to get there and back.
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ben.suffolk
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How do you correctly work out your LPG MPG v Petrol ?

#6 Post by ben.suffolk » Sun May 22, 2011 7:51 am

And if they have run out when you get there... etc

It not normally worth making any kind of major detour for cheaper LPG I find. Although as I have a countrywide account and that's only 64.6p I do try and fill there if I am close!

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Re: How do you correctly work out your LPG MPG v Petrol ?

#7 Post by Kempy » Tue May 24, 2011 1:12 am

ben.suffolk wrote:. Although as I have a countrywide account and that's only 64.6p I do try and fill there if I am close!
Is that with or without VAT?

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Re: How do you correctly work out your LPG MPG v Petrol ?

#8 Post by Gilbertd » Tue May 24, 2011 1:21 pm

Tecnobaz wrote:Does that mean on petrol price (139.9) vs lpg price (83.9) that the overall MPG is around 32ish?
No, the overall MPG is still 21.2, the running cost is the equivalent of 32 (or 35) mpg.

Quoting it like this only goes to confuse even more people where LPG is concerned. When I advertised my Saab for sale I quoted the mileage per tankful and somebody came back to me and said there must have been a typo as my figures showed it was only doing 28mpg on LPG (compared with 31 on petrol) when everyone knows that you get far more mileage on gas. People advertising a car for sale using comments such as, "Does 35mpg on LPG" when they are talking about a V8 Range Rover, only gives credence to the thought that not only is gas cheaper than petrol but you use less of it as well! It may give the equivalent running cost to 35mpg, but it doesn't do 35mpg.
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How do you correctly work out your LPG MPG v Petrol ?

#9 Post by ben.suffolk » Tue Jun 14, 2011 9:24 pm

Kempy wrote:
ben.suffolk wrote:. Although as I have a countrywide account and that's only 64.6p I do try and fill there if I am close!
Is that with or without VAT?
Inc vat

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Re: How do you correctly work out your LPG MPG v Petrol ?

#10 Post by Kempy » Wed Jun 15, 2011 11:05 pm

ben.suffolk wrote:
Kempy wrote:
ben.suffolk wrote:. Although as I have a countrywide account and that's only 64.6p I do try and fill there if I am close!
Is that with or without VAT?
Inc vat
Hmmm - a call to Countrywide may be in order - you are paying 3.8 pence/litre (inc VAT) less than me :evil:

If you don't mind me asking - how many litres/month are you using on your Countrywide account? (I have a feeling that you get a better price, the more LPG you buy from them).

ben.suffolk
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How do you correctly work out your LPG MPG v Petrol ?

#11 Post by ben.suffolk » Thu Jun 16, 2011 7:46 pm

Yes I have both our cars on the account and they are both 4l v8 landrovers althoughy wife only uses about 45 a week I tend to average more like 100.

I did drop them an email a while back when I thought it was getting expensive compared to local garages .

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Re: How do you correctly work out your LPG MPG v Petrol ?

#12 Post by tommo2009 » Thu Jun 30, 2011 1:35 pm

Friend of mine has just joined and he is paying 53 + VAT

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Re: How do you correctly work out your LPG MPG v Petrol ?

#13 Post by chuckie888 » Sun Jul 03, 2011 10:44 am

Multiply 80% of your petrol MPG to get LPG MPG.

Multiply this by (Petrol price/LPG price)

For example,

(31*0.8) = 24.8 * (1.319/0.779) = 41.99

Nytram
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How do you correctly work out your LPG MPG v Petrol ?

#14 Post by Nytram » Sun Jul 03, 2011 9:15 pm

The is a big assumption that LPG is 20% less efficient, this is not the case.

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Re: How do you correctly work out your LPG MPG v Petrol ?

#15 Post by Rosanbo » Mon Jul 25, 2011 10:50 pm

tommo2009 wrote:Friend of mine has just joined and he is paying 53 + VAT
Surely a typo? Or maybe not, that's 63.6p per litre inc VAT right?

How many litres does he use? Was this the opening price for his account without any bargaining?

I'm in South Wales and go past the Bridgend site every day. It would also be handy when driving down to Plymouth.
If I could get that price I would be happy to join Countrywide today and forget the 67p I'm currently paying on account at Abercynon.
Last edited by Rosanbo on Mon Jul 25, 2011 11:07 pm, edited 1 time in total.

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Re: How do you correctly work out your LPG MPG v Petrol ?

#16 Post by Rosanbo » Mon Jul 25, 2011 11:00 pm

Tecnobaz wrote:My outlander runs at 21MPG on petrol.
The last fill on LPG was 36l @83.9p per litre.

So thats £30.20 LPG and I covered 168 miles.

Now I'm lost as maths is not my strong point.

Can anybody work this out for me please.

Barry

You take the number of litres "L" divide by 4.546 = No. of Gallons used "G"

Then you take total miles "D" and divide by Gallons "G"

L/4.546 = G

D/G = mpg on LPG

To compare that into a petrol equivalent

Cost of LPG used "£" divided by cost of petrol per litre "P" = "I" No. of Imaginary petrol litres used to go distance "D"

£/1.34 = I

I/4.546 = "IG" Imaginary Gallons

D/IG = Petrol equivalent mpg.

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