Page 1 of 2

real world MPG

Posted: Tue Feb 26, 2013 2:38 pm
by awj85
so realistically what will i get out of my 4.4 X5?  IT IS LPG converted. I know that doesn't change the fuel consuption; just the cost of fuel!!  :))  Gas is about 72p a litre at the moment (if i recall) so a 800 mile round trip hopefully won't be too expensive.  Is there really a significant difference in fuel consumption between driving at say 65mph and 70mph??

thnaks all!!  :)

Re: real world MPG

Posted: Tue Feb 26, 2013 2:54 pm
by Imy
it will change the fuel consumption. you can expect aroun 2mpg less running lpg than petrol

Re: real world MPG

Posted: Tue Feb 26, 2013 5:55 pm
by murf62
I get about 19mpg on LPG (4.6is) on a run at about 75mph.  Generaly running around I get 200 miles on a tank which is about £42 worth.  Gas is 68p where I fill up in Cardiff.

I did some rough calcs before I bought it and would need to get 38mpg out of a diesel to be better off.  Going V8 was a no brainer for me.

Re: real world MPG

Posted: Tue Feb 26, 2013 7:11 pm
by Geezer
Really interesting thread guys.

I've just bought a 4.6is myslef last week and was seriously thinking of getting it converted. All the research I've done seems to suggest that you would loose approximatley 10% on the fuel economy on an lpg conversion as the gas burns faster (and at a higher temperature) than petrol.

Re: real world MPG

Posted: Tue Feb 26, 2013 7:48 pm
by Don Coffey
Hi awj85,

Good luck with the trip.  There really won't be that much difference between the two speeds and I would say 70mph would be far more comfortable than 65 in terms of ease of flow with the traffic. 

Don

Re: real world MPG

Posted: Tue Feb 26, 2013 8:13 pm
by awj85
ok guys, will go on 19mpg for the sake of my calculations  :blink:  i think last time i filled up the gas tank i got in 39 litre and cost about £29

thanks  ;)

Re: real world MPG

Posted: Tue Feb 26, 2013 9:00 pm
by murf62
Personally I wouldn't bother converting an 8-10yr old car, I would sell it as is and look for one already converted.  There are plenty around and they are not a lot more (£500-£800) than unconverted ones.  Look for one that has the LPG filler hidden away in the rear bumper under the tow bar cover, drilling a hole in the rear wing is just lazy.  Prins VSIs seem to be the most recommended systems.

http://www.prinsautogasuk.co.uk/Autogas ... eList.html

Re: real world MPG

Posted: Tue Feb 26, 2013 9:11 pm
by Don Coffey
If I was looking at a new (to me) car then for the sake of £800 I would consider LPG, but do not recommend swapping the current car as you have no idea what you are getting with the new one as opposed to the one you have.

Don

Re: real world MPG

Posted: Tue Feb 26, 2013 9:12 pm
by awj85
glad mine was converted before i bought it bought it (unfortunately i have to own an X5 which is 12 years old)  i was looking for a vehcile with no visible signs of it being lpg converted so thats why mine is filled up from the rear.  :) :)

IMHO BRC seems to be better than the prins systems from what ive read, and heard.

Image
Image

Re: real world MPG

Posted: Tue Feb 26, 2013 9:24 pm
by Don Coffey
[quote="awj85"]
Image
[/quote]
Your car looks really well.  And outside that great north eastern team.......Newcastle isn't it?............ :P

Don

Re: real world MPG

Posted: Tue Feb 26, 2013 9:33 pm
by awj85
lol wont tell my wife you said that don!  she is makem (i just happen to live here, thanks to MRSJ)
red & white ...........?  black and white.........?  ask me my opinion ..............  they're all a load of shite!  :D

Car looks even better now, as i took that pic just after the wheels were refurbed and i give it a quick wash over.  2 weekends ago, spent a bit of time on it, washed, clayed, washed, polished, waxed = looks quite good; for 12 yr old.    8)

Re: real world MPG

Posted: Tue Feb 26, 2013 9:42 pm
by Don Coffey
Then we need to see the evidence, post pics awj85.  ;)

Don

Re: real world MPG

Posted: Tue Feb 26, 2013 10:46 pm
by Benstan
[quote="Don Coffey"]
Hi awj85,

Good luck with the trip.  There really won't be that much difference between the two speeds and I would say 70mph would be far more comfortable than 65 in terms of ease of flow with the traffic. 

Don
[/quote]

I reckon that 5mph does make a difference but take the point about traffic flow.  Whatever you do, don't use the cruise (mpg-killer) and listen to Radio 4 or an audio book rather than pumping house!

Re: real world MPG

Posted: Tue Feb 26, 2013 11:15 pm
by murf62
Cruise is certainly not an MPG killer for me.  If I don't use it, everytime I look down I am doing over 120.  It's probably saved my licence a few times too (although last time I got banned I had it set, but that's another story. ;))

Re: real world MPG

Posted: Wed Feb 27, 2013 1:37 am
by macca
i know you asked about your 4.4 on LPG, but i had to add that i regularly get 850 to 950 km out of a tank in my 2005 3.0d sport, the diesel was a no brainer for me, with petrol at $1.50 a litre and diesel generally only .07 of a cent more  there was no justification for the V8, although i wanted one badly.

doing around 35,000 km per year made the petrol totally un economical