LPG conversion...

Sharq

Sharq

Sharq

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Joined
9 Mar 2003
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Ive read about the benefits through LPG and would rather have some first hand knowledge on the matter, regarding drawbacks.
Ive heard that converting your car to LPG causes stress on the engine head, which in time, causes it to crack. Is this true?

Is there any other things i should watch out for?

I know your suppose to run your car on petrol for about 10 miles eachday to keep the mechincal things inside the engine lubricated, as LPG doesnt have the lube compound that petrol does.

Thanks
 
as LPG doesnt have the lube compound that petrol does.
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These ain't two strokes, boyo :D No need to worry about running something on LPG 24/7 provided you can start it when cold!

The main thing to remember is to switch to petrol now and then (depending on systems) to run the injectors, fuel pump and so on to prevent seals drying or the injectors crudding up.

LPG is slightly higher octane than petrol, so you can get a gentle power hike out of it (nothing major mind).

No problems on any engine, provided it's in good condition (as it always should be) and the LPG system is set up well.

Having no personal experience with LPG systems myself, although my friend does work as a fitter for them, that's about all I've got to say! Feel free to correct me too :D
 
I thought lpg was of a lower octane?

I owned a Rover 827 with an lpg conversion and it was quicker on petrol, so you get less mpg on lpg...

Also lpg is supposed to burn very cleanly, so the oil lasts a lot longer and stays clear, so engine wear should be reduced.
 
Well - as far as my memory tells me it's 100+ octane (sometimes as high as 110?).

Like you said though, you do get a lower overall MPG but it's offset by the reduced cost. Wonder how long that'll last mind :(
 
Best thing I did was convert my Jeep to LPG

I do get about 30miles to the tank less, and its not as quick when running LPG.
My car, and I think all duel fuel cars, start on petrol, and run for a couple of minutes in petrol before switching over automatically, so you dont need to make sure you run it on petrol. It already does that :)

My car does about 18-20mpg average on lpg, it costs me £23 to fill it up about 60 litres!
I am seriously saving £30-40 a WEEK, as I fill my car every week.
 
far as i know lpg burns differently (slower burn?) than petrol, even though it has a higher octane rating you still lose a little bit of power, nothing huge though

it is possible to start a car engine on lpg but i think you need to have a multipoint injection system rather than the fogger type (fogger is where the system just dumps lpg into the airbox of the car, multipoint is where the system uses a 2nd set of injectors next to the petrol ones)

i know a couple of people who run LPG on big engined cars (Carlton GSI's and Rangerovers mostly) and they say that the loss of power is hardly noticable

they also say that their actual fuel economy goes down by 1 or 2 mpg, i.e. a rangerover that'll do 18mpg on petrol might only get 16mpg on gas, but this is more than offset by LPG being half the price

:)
 
Downsides to lpg -

20% less mpg

Higher burn temperatures

Slower to warm up from cold

Greater resistance to the ignition system

The LPG exhaust gas can smell a bit more


Upsides -

Its 40p a litre (4p tax rise in sept)

The gas is stored as a liquid, vapourisation will aid engine cooling

LPG does not degrade the oil even half as much as petrol

LPG exhaust gases are not lethal, they are not much worse then cooking gas. Calor gas bottles can be used even if extra tax is paid.

LPG mixture can vary but octane can be as high as 130, far over 100 usually

Can be fitted to turbo and performance engines without loss of power though fitting an entirely new injection system and ecu is expensive compared to a simpler carb feed










If your car runs on unleaded it should be fine on lpg almost all modern cars are, some run on lpg exclusively and in fact this is far better for the engine because the oil will still be clean when you come to change it. Some state engine lifetime is doubled when using lpg due to this effect.

Petrol is a solvent, theres nothing in there to preserve the engine especially, I can only think of overfueling on high psi turbo systems, if the LPG was directly injected then it would be even better.
But with a cheap system there might some issues since the gas does not cool directly like petrol would, water injection as a replacement maybe?

What car do you have
 
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karoshi said:
it is possible to start a car engine on lpg but i think you need to have a multipoint injection system rather than the fogger type (fogger is where the system just dumps lpg into the airbox of the car, multipoint is where the system uses a 2nd set of injectors next to the petrol ones)

i know a couple of people who run LPG on big engined cars (Carlton GSI's and Rangerovers mostly) and they say that the loss of power is hardly noticable

they also say that their actual fuel economy goes down by 1 or 2 mpg, i.e. a rangerover that'll do 18mpg on petrol might only get 16mpg on gas, but this is more than offset by LPG being half the price

:)
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My system has a full set of 8 injectors, and its not a small engined car by any means... there certainly is a small loss of power, and it IS noticable.
 
austinpowers said:
Also lpg is supposed to burn very cleanly, so the oil lasts a lot longer and stays clear, so engine wear should be reduced.
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Yes, the oil stays clean for a long time even when driving round town.My dad's fleet of vans were converted to lpg in 1973-ish, back then it was a rather crude system with what looked like a gas ring in the air filter housing and a huge gas cylinder located sideways behind the seats. They were fitted with a switch on the dash to change from petrol to lpg. They only ran this system for a couple of years because the price of lpg started getting forced up by tax and it wasn't worth doing it anymore. There were some incidents during that time though. One driver who tried to start the van on gas lost his eyebrows after the van actually fired and ignited the gas that had escaped prior to it firing up.
 
I'd suggest you talk directly to your vehicle manufacturer regarding engine compatibility before taking the plunge.
I considered LPG a few years ago and talked directly to Toyota. There response was that they would not condone the use of LPG with any of their engines at the time, implying that any warranty you might have would be invalid.
No idea how other manufacturers view it, but the last time I looked, there were few groups saying that their engines were suitable.
 
Apart from the mechanical things to look for, one important fact to consider, is how close to your normal motoring route is a fill up point. It could be a pain having a 15 mile round trip to fill up.
 
i was thinking about converting a 02/03 Mondeo, LX or ghia x (Prefered, dont know if its relevent), 1.8/2.0.

Some of you stated that you dont have better MPG from LPG but you save a lot on the cost. So how big is a Tank? I dont want to be filling every 200 miles and i dont want the tank to be HUGE!! I will need a large proportion of the boot space for luggage etc

When converting a car to run LPG, how professional is the Job? Would it be a simular setup to a factory fitted system? i.e the LPG filler would be where the standerd Petrol filler is?

Would it be more efficient/less likley to run into problems if i bought a car with a factory fitted LPG system? Like a volvo S60? There going for about 7k, with high mileage (90k+). For arguments sake, lets say i bought a Volvo S60 which has been looked after, would the engine reach 150k+ ?

ive seen some Mondys/astras/vectras with LPG systems factory fitted. Although there slightly cheaper and have less miles, they dont have the Luxeries a Volvo has. I would be keeping the a minimum of 2 years, so i would like leather, cruise control and all the other "Necessities" to keep me interested ;)

i'm having trouble determine which would be better for me, a conversion or factory fitted LPG system? :confused:
 
My step dad recently bought a K reg Discovery (3.5L V8) that had been converted to LPG.
It has 2 big tanks under the car, costing about £20 to fill them both with LPG and it gets 150-170 miles from those 2 tanks.
That works out at about 35mpg when comparing it to petrol (if my calculations are correct). Obviously the actual mpg is a lot lower (around 15mpg) but that's taking into account of the cost difference between LPG and petrol.
 
So•H I Gunit H**•mp3 said:
Some of you stated that you dont have better MPG from LPG but you save a lot on the cost. So how big is a Tank? I dont want to be filling every 200 miles and i dont want the tank to be HUGE!! I will need a large proportion of the boot space for luggage etc
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The tanks vary in size, they can be fitted to where the spare wheel was (toroidal ), boot or on a 4x4 underneath
My tank is 80 litres and there is enough space still, tank pressure means only 80% fill can be used so thats a real capacity of 64 litres. I get about 300+ miles on lpg alone from that

So•H I Gunit H**•mp3 said:
When converting a car to run LPG, how professional is the Job? Would it be a simular setup to a factory fitted system? i.e the LPG filler would be where the standerd Petrol filler is?
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My lpg filler is in the plastic bumper below the petrol cap. Conversion jobs vary on the company that does it, there is no regulation apart from an industry body who give a few guidelines like a tradesmens guild. Factory fit has to be best option imo, there was a guy on here who got a 10 grand Volvo with LPG because his dad was paying but refused to pay for his petrol. I forget his name though sorry, maybe still searchable.

So•H I Gunit H**•mp3 said:
For arguments sake, lets say i bought a Volvo S60 which has been looked after, would the engine reach 150k+ ?
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Yes unless it was badly maintained, the odds of it reaching 150k are much better then for a petrol car. You need to renew the ignition parts more regularly, the rest is good

So•H I Gunit H**•mp3 said:
i'm having trouble determine which would be better for me, a conversion or factory fitted LPG system?
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I met a friendly man at the lpg pump once who mentioned his nissan micra cost no more to buy with lpg then the petrol equalivant. Considering a conversion can cost from 300-3000, the best point of fitting would be factory if you dont mind the normal amount of new car depreciation cost anyway


A few pictures here -
http://www.mvturbos.com/lpg.htm
 
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Hmm, ive decided am going to purchase a factory Fitted LPG system, possibly a Volvo. As soon as i saved my budget + insurance, ill be getting me one of these LPG cars. Ill keep you lot updated.

Thanks for all your help, much appreciated! :)
 
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