Diesel vs LPG?

Turboselecta · Unread post by **Turboselecta** » 26 May 2008, 14:05

Are old diesels losing their edge?? My ZXs are only averaging 46mpg, used to be 48. If the price of diesel was sensible, on a 70% soya mix I'd be well ahead of the frugal petrols. (Does anyone have a cogent reason for the price of diesel?).
On pure economic grounds, should we be looking at lpg converted petrols instead??!

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howiedean · Unread post by **howiedean** » 26 May 2008, 14:21

Turboselecta wrote:Are old diesels losing their edge?? My ZXs are only averaging 46mpg, used to be 48. If the price of diesel was sensible, on a 70% soya mix I'd be well ahead of the frugal petrols. (Does anyone have a cogent reason for the price of diesel?).
On pure economic grounds, should we be looking at lpg converted petrols instead??!
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The command for diesel has rocketed since the introduction of the newer tax bands, combined with the demand for diesel by the HGV's. The amount of diesel, petrol etc that can be made from crude oil remains the same, so if demand for one goes up then there will be an excess of another, hence the price will go up.
I've thought about getting an LPG converted car....anyone got a Xantia V6 for sale, converted of course?

Regards

deian · Unread post by **deian** » 26 May 2008, 16:21

The price of LPG is going up steadily now, locally to me i've seen 58.9p per litre of LPG.

LPG doesn't run as efficiently as petrol, i'd say 15% less efficient, so if you have a car heavy on petrol lets say it does 25mpg, and you take away 15% you get 21mpg for say 60p per gallon.

Plus there is the need to convert a car to LPG, with the Xantia V6, it would have to be a sequential system not single point (down the intake) so the kit would be around £1500. It quickly becomes too much hassle and cost... for my liking anyway.

Maybe it would be a bit more economical than a diesel, but not more economical than the most frugal diesel.

MikeT · Unread post by **MikeT** » 26 May 2008, 17:33

It seems no matter which way we turn (SVO LPG etc), prices will rise unacceptably. Having just heard a news story about the changes (read increases) to road fund license (what a laugh that term is!) in the near future. It was said that cars seven years and over will suffer the most substancial increases (depending on CO output).

As a result, I'm seriously considering the wisdom of spending any more money on maintaining my cars if I won't be able to afford to tax them.

I predict they will also lose any remaining value, meaning more will scrapped.

vince · Unread post by **vince** » 26 May 2008, 20:23

I stay stick with Diesels.....

i used to be a steadfast petrol man...id never entertain the idea of a diesel until i watched a program on sky with robbie coltrane where he demonstrated the amount of fuel actually used by a diesel engine to convert to kinetic energy (movement) with a petrol engine and the same amount of fuel.....it was shocking....the petrol engines expel most of it as loss....i just pictured my pound notes fluttering out the window as i drive and i made the switch. ive never been back since and dont intend to.

I can see the reason for the LPG idea but you lose alot of boot space or have a tiny tank that fits where your spare wheel goes, and it costs the best part of £2000 to get the job done. Ok so they are cheaper at the pump but as the previous guy said, they are still less efficient engines and all it will take is a rise in the price of LPG (which will come with demand as it has done with diesel) and your back to square one again only an extra £2000 lighter for the conversion cost....

Pressure on fuel will see it come back down and the cost camouflaged elswhere....like road tax for example.

The only reason fuel is so dear is because of the tax duty on it...its around 75% which is down to the government......in my opinion the next lever to be used by government will be to drop tax on fuel bringing it back in line and re-capture the hearts of us britains but then move it elsewhere so they dont lose out.

Dont get me wrong...the price of a barrel of crude oil has doubled....but that still doesnt explain why we are the most expensive country in the world for fuel (to the best of my knowledge), its taxation.

You dont hear on the news that a new oil field has been discovered off the coast of brazil which is bigger than the whole of the middle east oil reserves do you?.....why? because there would be public outcry at why prices are increasing with more supplies found. Its true, i get an inside track business publication which detailed it all in....still not been on the news though

There is more than meets the eye to alot of this stuff.....

Finally please accept my apologies for my soap box moment....i wont do it again i promise

Unread post by **Peter.N.** » 26 May 2008, 22:04

I would go with Vince...

If the price of fuel keeps increasing to the point of us having to economise, a diesel driven gently will give much more of an improvement in mpg than a petrol driven engine under the same conditions. A petrol engine needs a constant fuel/air mixture, I think it is about 13/1. A diesel has a full charge of air on each cycle the power out only being regulated by the fuel input, so it will run on a very weak mixture.

My XM 2.1td estate will return well in excess of 50 mpg on the motorway, driven with some restraint, try that with a petrol car weighing over 1500 kilo's.

deian · Unread post by **deian** » 26 May 2008, 22:29

Peter: you and your 2.1td xm, you don't stop do you ...

Seriously... i agree! I liked that engine in the Xantia, an XM would be well nice to have!

deian · Unread post by **deian** » 26 May 2008, 22:31

...still an LPG'd XM V6 would be ultimate choice... why not in the Xantia?... well the XM has a bigger boot doesn't it!

Penguin · Unread post by **Penguin** » 27 May 2008, 10:21

Vince, whilst some of what you say is true regarding the price of fuel it is not the whole story. In 1998 I worked for an oil company (service provider not driller) and the industry was in a slump. Brent Crude reached a low of $5 a barrel, it is now circa $135 a barrel, so 'doubled' doesn't quite cover it. The price of oil is high because of demand and speculators abandoning the weak dollar and putting their money into commodities. You are quite correct that we are taxed heavily for our fuel but it has always been the case, in some respects this has actually cushioned the percentage rise that we pay for our fuel. If we were only paying for the cost of the fuel (+profit) then the fuel would have gone up significantly more in percentage terms than it has, admittedly we would still be paying less, but you get the point.

I did see mention on the BBCs website of that find in Brazil. It does look promising for them although the reserves are still only estimated at this point.

Anyway, back to Citroens. My 1.9td is disappointingly uneconomical to drive. I'm only getting mid 30s to the gallon and is not really any more economical than a decent petrol car, however, I am shortly going over to WVO and possibly WVO derived biodiesel and have sourced supplies from a number of outlets. Once I get the filtration plant up and running I won't be too bothered about the Xantia's poor mpg. I believe Xantiaman is also considering this route judging by posts on a different forum.

Unread post by **myglaren** » 27 May 2008, 12:26

In addition to the Brazil discovery I have seen reports of a large field in Venezuela and one in Canada.

Unread post by **CitroJim** » 27 May 2008, 13:00

myglaren wrote:In addition to the Brazil discovery I have seen reports of a large field in Venezuela and one in Canada.

They, I believe, are tar oil deposits (tar sands in Canada) and therefore very thick. These apparantly need more processing than light crude and because they're heavier, don't yield the same amount of petrol and diesel as easily, hence it's more expensive to process.

Likewise there are still fair old deposits of shale oil in Dorset but because it's a bit environmentally sensitive down there, extracting it is not easy.

Oil in the form of tar sands and shale is apparantly very abundant and will last donkeys years, the problem is economically extracting and processing it.

Penguin · Unread post by **Penguin** » 27 May 2008, 14:19

citrojim wrote:Oil in the form of tar sands and shale is apparantly very abundant and will last donkeys years, the problem is economically extracting and processing it.

I think at $135 a barrel its becoming less of a problem!

Unread post by **myglaren** » 27 May 2008, 16:12

Penguin wrote:
citrojim wrote:Oil in the form of tar sands and shale is apparantly very abundant and will last donkeys years, the problem is economically extracting and processing it.
I think at $135 a barrel its becoming less of a problem!

We may have to revert to the wartime expedient of running our cars on chickenshit - in a trailer towed behind the car.

Turboselecta · Unread post by **Turboselecta** » 27 May 2008, 17:25

Absolutely not! Far more useful on the allotment!
Old Honda Insight anyone?? (86mpg)

Unread post by **Peter.N.** » 27 May 2008, 22:57

The buses used to run on coal gas in a large bag on the roof, you might be able to do the same with natural gas, might have a few problems with health and safty though

If oil stays at this level or more, I can see them opening up the coal mines again.

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Diesel vs LPG?

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