Approx MPG figures

[Julian_P]

Firstly a hello to all on this forum as this is my first post

I've been wondering about LPG for a while now. I can see that if you have a thirsty car like a V8 Range Rover then LPG fuel could save you a fair wad of cash over the years. However I'm at the opposite end of the spectrum

My wife has an elderly Peugeot 306 Diesel with 270,000 miles on the clock, still going well, but the time for a replacement is getting near. She does a fair annual mileage and the vehicle always gets about 55mpg. Now, I'm thinking about a similar sized vehicle to replace it with and wondered about a petrol engine converted to gas. What would be the savings, ie what sort of MPG could I expect from a Pug 306 sized vehicle running on gas? I'm aware that LPG is a little more than 1/2 the price of Diesel fuel, so really I'm just wondering if it's easy to make economic sense or not?

I would plan to convert the vehicle myself if I couldn't find one already done on ebay.

Julian.

[tom-madbiker]

if the pug has a bosch fuel pump and is the non common rail type run on waste veggie oil just filter it first and pour it in 100% mix i ran my 406 for 2 years on the stuff 5 pence per litre the way forward only thing is you have to change the fuel filter every month

[sijones]

if the pug has a bosch fuel pump and is the non common rail type run on waste veggie oil just filter it first and pour it in 100% mix i ran my 406 for 2 years on the stuff 5 pence per litre the way forward only thing is you have to change the fuel filter every month

Not legal though...

[tom-madbiker]

erm im not sure when i did it you could use 2500 litres a year before paying road fuel duty there was a 3 year exemtion dunno if the kept it tho

[Gilbertd]

I believe it is legal up to a certain amount a year (2000 litres I think but may be wrong) but as I said to a guy at work that runs on waste veg oil, where do you fill up when away from home, MacDonalds?

To answer the original question. If you get a petrol car that does 35mpg on petrol, it should do around 30mpg on LPG. With the difference in cost of LPG means that the running cost will then be the same as if you were doing 55-60mpg on petrol or slightly more on diesel (as it is that little bit more expensive).

[sijones]

I believe the exemption was for turning waste veg oil to bio diesel, and you still had to declare how much you made and used, and you would be exempt under the amount.

You couldn't just take veg oil and stick it in your tank and be ok because that is just cheating the tax, that why they did the above, and if you didn't declare then basically you would be treated like using red diesel, not paying excise duty... blah blah...

[Julian_P]

I believe it is legal up to a certain amount a year (2000 litres I think but may be wrong) but as I said to a guy at work that runs on waste veg oil, where do you fill up when away from home, MacDonalds?

To answer the original question. If you get a petrol car that does 35mpg on petrol, it should do around 30mpg on LPG. With the difference in cost of LPG means that the running cost will then be the same as if you were doing 55-60mpg on petrol or slightly more on diesel (as it is that little bit more expensive).

Thanks for the reply, it sort of confirms what I had been thinking in that with the installation costs, or parts cost if DIY then it's a fairly long payback period when compared to the undoubted better economy of a Diesel.

My Wife's pug does have the Bosch VE pump fitted but it looks to me like the days of cheap old veg oil are behind us as everyone is on the bandwagon. I did do a 'trial' a few years ago, just for fun really and tried some new veg oil blended with regular diesel and it ran very well. If anything the engine seemed to have more power and had a slightly deeper, more pleasant engine note!

Julian.

[Gilbertd]

There was some calculations done a while ago using the fuel consumption figures for a factory fit Vauxhall on LPG, the same car on petrol and the equivalent car on diesel. Ignoring road tax and servicing costs (which would also need to be taken into account), going purely on fuel costs, petrol was the most expensive to run by quite a margin, with diesel second and LPG the cheapest but not by much. However, the resale values of cars with LPG conversions already fitted aren't much more than the petrol only ones and usually quite a bit cheaper than diesels. Buy a car that is already converted and you don't have the payback to worry about, you are into a saving straight away.

[Julian_P]

Buy a car that is already converted and you don't have the payback to worry about, you are into a saving straight away.

That's a good point, there's always plenty on ebay, and I guess there's some used car dealers that specialise in LPG fired cars? I don't know of any but google is normally a good starting point!

Cheers Julian.

[Gilbertd]

Downside to a specialist dealer is that they will put a premium on because a car has a conversion on it, whereas a quick check on eBay shows that there are currently 602 converted cars on there at the moment. Plenty to choose from then.....

[reggieroo]

The best option is to find one that has been converted, that's what I did. It may take a little longer to find your desired car but it will be worth the hunt.

[Julian_P]

The best option is to find one that has been converted, that's what I did. It may take a little longer to find your desired car but it will be worth the hunt.

This looks like a safe bet, any comments?

ebay Item number: 330732193497

One other thing, I have LPG central heating with a 2000L tank in the garden, is it possible to get liquid gas out the things and into the car? I know it's against the law, and the price isn't much less than at forecourts so we don't need that aspect doing to death but I was just wondering....

Cheers Julian.

[Gilbertd]

Looks very tidy.

Your LPG tank for heating will draw vapour off the top, to fill a car you need liquid from the bottom and a pump to transfer it.

[Julian_P]

Looks very tidy.

Your LPG tank for heating will draw vapour off the top, to fill a car you need liquid from the bottom and a pump to transfer it.

Some years ago I changed from Calor to Shell. Back then the suppliers had to use their own tanks and hence Shell installed their own. After they did this they pumped the remains of the LPG in the Calor tank into there own one. They did this via a pipe (obviously!) and a pump which was little Honda engine powered thing. There was a sight glass with a little impeller in it and you could see the flow of the LPG, I'm thinking that these tanks must have an outlet that draws from the bottom?

Julian.

[sijones]

One other thing, I have LPG central heating with a 2000L tank in the garden, is it possible to get liquid gas out the things and into the car? I know it's against the law, and the price isn't much less than at forecourts so we don't need that aspect doing to death but I was just wondering....

I believe you can get tanks that allow both, you then choose how you pay the tax duty, it being different for house versus car use, so you buy lpg with the car duty paid already and then exempt your house or the other way round...

[Gilbertd]

Out of interest, how much do you pay for bulk LPG? Bear in mind that VAT on domestic heating fuel is only 5% so if you declared that you were using some to run the car, you be paying the purchase price, plus the road fuel duty, plus VAT on the total at 20%. HMRC like to make you pay tax on tax..... I suspect you'll find that buying it from the local filling station is cheaper!

[Julian_P]

60pence/litre + VAT. That was last summer and I haven't purchased any since. Shell gas no longer do distribution and Avanti now do it.

Julian.

[Gilbertd]

Just adding the VAT at 20% makes it 72p per litre, with the RFD added as well, it's going to be much cheaper from your local filling station!

[Julian_P]

Although getting caught would perhaps be very unlikely as the fuel has no dye or chemical marker added. I guess HMRC would have to catch you filling and also driving on the highway?

Julian.

[Gilbertd]

Dead easy, your supplier is obliged to inform them if you have a bottom take off on your tank.....

I've got about 600 litres of heating oil in my garden which is the same stuff as diesel but without the lubricants. I'm reliably informed (by an HMRC diesel dipper) that you can run a diesel on 100% heating oil (or kerosene as they refer to it) but your fuel pump will be worn out in 10,000 miles, but if you mix it 60/40 with diesel the diesel supplies sufficient lubricant. Good job I don't own a diesel.