Is LPG really as 'cost efficient' as diesel?

[Mike_C]

OK, we all know how everyone states that LPG costs as little to run as a diesel, etc etc, but is it actually true?

Here's the scenario - I currently run a BMW 330Ci which returns around 26/27mpg on a mixed drive to and from work each day and over 30mpg on a run.

I have decided to sell the BMW and get either a P38 Range Rover or a Discovery II.

I have been looking for a diesel (so either a DSE or TD5 ES) as I need reasonable fuel economy, and both should return similar figures to what I currently get from the BMW.

What I want to know is, in the real world, would a 4.6 V8 P38 or a 4.0 V8 Disco II on LPG be as efficient (in terms of £) as a diesel? It currently costs me about £75 to fill up the BMW, from which I get 320 miles to a tank in normal use, based on around £1.36 a litre. Has anoyne got any comparable diesel and LPG figures for me?

Because lets be honest, a V8 is ALWAYS preferrably to a diesel, but if in reality the best an LPG'd V8 manages is an equivalent 20mpg then I'll go for the dirty derv ;-)

Cheers!

[5lab]

lpg does approx 80% of the mpg of the petrol, and marginally less power (~5% iirc)

so you'd have to work out whether the diesel mpg @ £1.40 is better than the petrol mpg @ 80p. There's also some thought to be given to the lpg installation/headaches

[LuS1fer]

There is a guy near me who has clocked well over 100k in his 2005 Mustang GT on LPG and has not been remotely tempted to buy a diesel.

[5lab]

LuS1fer said:

There is a guy near me who has clocked well over 100k in his 2005 Mustang GT on LPG and has not been remotely tempted to buy a diesel.

i'd say that's a bit different though. A mustang needs a v8. a big 4x4 doesn't (in my opinion)

[Mike_C]

5lab said:

lpg does approx 80% of the mpg of the petrol, and marginally less power (~5% iirc)

so you'd have to work out whether the diesel mpg @ £1.40 is better than the petrol mpg @ 80p. There's also some thought to be given to the lpg installation/headaches

I'd say a 4x4 definitely benefits from having a V8!!

Well, "if" I got 14mpg from the V8, the difference is a couple of quid (based on 80p /litre for LPG against £1.40 for diesel). However, if I was only getting say 11mpg (roughly 80% of 14mpg, which is what I got from my old 3.9 V8 RRC) then it's an extra £20 over my usual 320 mile tankful! So quite a difference!

[richardxjr]

Had a 4.6myself, though not LPG'd. Diesel RR is DOG slow and usually poorly spec'd, and the TD5 is problematic.

So go for it!

[Greg_D]

some (probably wrong) maths

assuming the petrol does 15mpg and diesel does 22
80% efficient lpg @ 80ppl = £1/ltr equivalent = £4.55 gal
diesel =6.37/gal

10,000 miles@ 15mpg= 666 gal@4.55=£3030 in lpg
10,000 miles@ 22mpg= 454 gal@6.37=£2,891 in diesel

that's assuming the lpg is already fitted, but if it is cheaper to buy then that clouds your decision that bit more.

In basic terms, get the diesel!!!

[smileymikey]

Would love to buy a Jag or big fat Merc with lpg. Used a Jeep Cherokee with it fitted when I needed to tow. Seemed absolutely fine and it gave no problems

[Texpis]

Greg_D said:

some (probably wrong) maths

assuming the petrol does 15mpg and diesel does 22
80% efficient lpg @ 80ppl = £1/ltr equivalent = £4.55 gal
diesel =6.37/gal

10,000 miles@ 15mpg= 666 gal@4.55=£3030 in lpg
10,000 miles@ 22mpg= 454 gal@6.37=£2,891 in diesel

that's assuming the lpg is already fitted, but if it is cheaper to buy then that clouds your decision that bit more.

In basic terms, get the diesel!!!

Assuming your maths is right and assuming he wants a P38, for the sake of 150 quid a year you would recommend a slow lumbering diesel over a well spec-ed sprightly 4.6?

Mick

[busta]

Texpis said:

sprightly

[Texpis]

busta said:

Texpis said:

sprightly

Comparatively

[Greg_D]

Mick,

absolutely not, i would have the petrol in a heartbeat.

not forgetting that there are other factors at work here as well,

will lpg rise at a quicker/slower rate to diesel in future
conversion costs of a couple of grand if not done already or a higher asking price if pre converted
less expensive bits to go pop on a v8 so servicing/repairs should be cheaper

but you are right, if you are looking at FFRR, you shouldn't be trying to do it on a shoestring,

embrace the consumption...

[R60EST]

Fuel consumption with or without LPG will be the least of your worries with a P38 . It will cost much more in repairs , replacement parts and maintenance. I don't know what your budget is but I'd consider an X5 4.4 V8 and then LPG that.

Older 4.4 X5's are hovering around the £5k mark now and LPG can be installed from £1300 upwards.

X reg X5's fall into the old tax bracket system £215 per annum

[richardxjr]

There is certainly a good deal of luck involved with buying a '38.

Mine over 5000 miles cost me £70 for oil and a service kit, and I sold it for £500 more than I bought it for.

Twas a lovely thing and not once did I get asked for recreational pharma

[bozmandb9]

LPG is more economical than diesel on a Range Rover (unless you're talking a newish TDV8, and even then it's marginal).

My 4.2 Supercharged gives around 250 miles on 70 litres of LPG, so that's 16.3 miles per gallon, I'm buying LPG at 69.9 pence per litre, so that would equate to 32.6 mpg. Take off some for the petrol used in start up etc, and you're still talking upper 20's, and that is with spirited driving making the most of a Supercharged 400 bhp engine.

Most TD6 users struggle to get 23 unless they are nursing it like crazy. I would imagine the TD6 is quite a lot better than the 2.5 DSE. So I would say LPG all the way. The petrol V8 suits the Range Rover perfectly as well, I would imagine that the guy saying a 4x4 doesn't need a V8 needs to actually drive a Range Rover, because the reality is the opposite, you certainly need a powerful engine to shift a couple of tons of RR, a 4 cylinder would be a joke, a 6 cylinder would really struggle, and I've never heard of a straight 8! The TD6 does OK because of the diesel Torque, but it's sluggish unless chipped.

Just my humble opinion having owned the 4.4 L322, driven the TD6 to Sweden and back, and currently owning the S/C.

[R60EST]

richardxjr said:

There is certainly a good deal of luck involved with buying a '38.

Mine over 5000 miles cost me £70 for oil and a service kit, and I sold it for £500 more than I bought it for.

Twas a lovely thing and not once did I get asked for recreational pharma

You were definitely one of the lucky ones. That certainly isn't the norm. Don't get me wrong , they look fantastic and are great to be in , when everything works there is nothing else that comes close. Sadly , the when everything works part is only about 10% of the time in my experience.

The 4.6 engine is really thirsty compared to some of the other V8 offerings of a similar size

[eliot]

P38's can be a money pit if you have to pay someone else to do all the work. But if you do the work yourself, the parts are cheap and plentiful and there's lots of information and advise on fixing them up. I've got a faultmate diagnostics for mine and he fixed every single fault on the unloved one that I bought back at christmas (see profile link to my site)

[300bhp/ton]

5lab said:

lpg does approx 80% of the mpg of the petrol, and marginally less power (~5% iirc)

so you'd have to work out whether the diesel mpg @ £1.40 is better than the petrol mpg @ 80p. There's also some thought to be given to the lpg installation/headaches

Those figures of 80% and 5% depend highly on the type of LPG system though. Modern multipoint ones are vastly superior to older single point ones.

[300bhp/ton]

Mike_C said:

OK, we all know how everyone states that LPG costs as little to run as a diesel, etc etc, but is it actually true?

Here's the scenario - I currently run a BMW 330Ci which returns around 26/27mpg on a mixed drive to and from work each day and over 30mpg on a run.

I have decided to sell the BMW and get either a P38 Range Rover or a Discovery II.

I have been looking for a diesel (so either a DSE or TD5 ES) as I need reasonable fuel economy, and both should return similar figures to what I currently get from the BMW.

What I want to know is, in the real world, would a 4.6 V8 P38 or a 4.0 V8 Disco II on LPG be as efficient (in terms of £) as a diesel? It currently costs me about £75 to fill up the BMW, from which I get 320 miles to a tank in normal use, based on around £1.36 a litre. Has anoyne got any comparable diesel and LPG figures for me?

Because lets be honest, a V8 is ALWAYS preferrably to a diesel, but if in reality the best an LPG'd V8 manages is an equivalent 20mpg then I'll go for the dirty derv ;-)

Cheers!

Have you considered LPG and diesel? It's what I'm planning on my modded Series III (when it's eventually finished!!)

[300bhp/ton]

richardxjr said:

the TD5 is problematic.

Td5's are usually very robust.