classic lpg running cost

[JIMBOBLY]

how are we all doing?ive got a rangie 3.9 efi,im wondering what sort of figures you people you are getting,do you think its cheaper to run lpg than a diesel,and what lpg systems are you running,whats the best etc,any help would be much appreciated,jim.

[Rainbird]

At best, you'll get the same mpg from gas as you would from petrol as the octane rating from lpg is less than that for petrol, whereas a diesel will return 30 mpg on a good day. 

The cost savings from gas come because of the tax break on it which means that a litre costs a lot less.  Unless I'm mistaken, it can cost around

[bogie]

DIESEL -  Veg oil all the way  55p a litre!!!

[SteveGoodz]

What mileage you actually get (no matter which fuel) will depend on a number of factors, not least of which is how heavy you are with your right foot  :D

I run a 3.9 efi Discovery automatic and have previously owned a 3.9 efi manual Discovery too. MPG on LPG should be very similar to petrol. Although LPG has a lower octane rating than petrol the big engine reduces the notable effect that gives. With my manual motor is used to get 17mpg on petrol and 16 on gas ~ figures collated over 2 years of ownership. The current auto motor gives an average of 13mpg on petrol and 12 on LPG ~ figures collated over the past 18months of ownership.

Savings on LPG only come from the lower cost of the fuel. For years there have been rumours that successive governments are going to increase the vat and fuel duty but it hasn't happened yet and, in my view, is unlikely to for the foreseeable future.

Only you can decide if the cost of conversion makes economic sense but I do a fairly high annual mileage and the payback time would be less than 12 months - assuming a

[Range Rover Blues]

My LSE can do 12.8MPG.  It might get better with a new cam but that will have to wait.  My sister got a bit better from her 3.9, it had a new short engine and reconned heads with a OMVL Dream XXI multipoint LPG system.

Our TDi can do around 27-29mpg, so running costs are comparable but the V8 has the edge on power, plus is more refined to drive.

My multipoint cost

[squaddie_fox]

I have had my LPG converted V8 running for about 600 miles and used around 120 quids worth of gas at 55p a litre. So, I'm hoping my mental arithmatic hasn't let me down, It stands at around 12-13MPG. I have a bit of a heavy foot but that is quite good considering i run fully laden all the time and have oversize tyres.

[Range Rover Blues]

With those tyres you need to add around 10% to your MPG, plus the extra weight in the wheels will reduce your true MPG, so not that bad really for a well used V8.

High fuel consumption is the first symptom of cam wear.