mbabin28
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| posted on 9/4/10 at 08:32 AM |
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Car to run on only LPG - easy?
Hi there,
I am planning on building a kit car in the future and am one of them type of people who has to have everything planned out and organised beforehand.
If the price of LPG is still cheap in the future, I was thinking how easy it would be to run my car solely on LPG. I have seen a lot on the internet
about common cars running LPG AND petrol, however i don't think there will be much available space for another tank and would rather have one
big tank of LPG rather than switching between the two. Does anyone know anyone who has done this? Any further thoughts I am overlooking?
Thanks in advance,
Marc
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deezee
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| posted on 9/4/10 at 08:44 AM |
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You can certainly run your car on only LPG only, however it will freeze in colder weather making it a nightmare to start and get warm. We (like many
companies) have warehouse vehicles that run on gas. They are awful in winter.
Also the MPG for LPG is lower. Your small kitcar, with a small tank, will only do small distances.
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zilspeed
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| posted on 9/4/10 at 08:52 AM |
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Like a few others on here, I have done an LPG conversion previously.
Once you get your head around it, it's no big deal.
You can certainly get old fashioned mixer systems which will start and run on gas no problem.
It's not usually recommended by the manufacturers due to there needing to be a source of heat to stop the vapourizer from freezing. In practice,
and in my case, my 1.6 litre 100bhp engine could be run on gas within seconds of a cold start, so it's not a huge issue.
More of an issue is finding a modern injection system which will actually allow purely gas only operation. It would be mad to fit an old fashioned
mixer system to a modern injected engine.
My system was completely configurable but even though starting and running on gas from cold was an option, in practice it didn't do it. The
readouts on the laptop said it was doing it, but the audible firing of the solenoids when it actually changed over onto gas confirmed that the
initial firing of the engine was on petrol.
My suggestion is that you fit a small petrol tank. That way you get to start on petrol and do the bulk of your running on gas.
Now, having said all of the above, make sure that you can get gas in your normal running without having to make special journeys to get it. Also make
sure you're comfortable with having to plan your journeys around fuel stops.
Some parts of the world are not well covered at all. If you factor in that you can't always have a great range due to the slightly increased
fuel consumption and because you can only 80% fill your tank, it all starts to get complicated.
It makes a gas only car something not to be considered lightly.
If you have a sports car, you'll want to go on blats around the country. If you have a gas only car you certainly can't join in events
like the North East Sevens Big Blats, because you wouldn't have the range between fuel stops and the northern loop especially there would be no
gas, so you don't get to do the Applecross road.
This could all be a bit abstract, but food for thought, I'm sure.
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scootz
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| posted on 9/4/10 at 08:54 AM |
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I looked into running solely on LPG a while back. The method behind my madness wasn't based on fuel cost-saving though - more on the
performance (higher-octane, etc.).
It appears that Liquid-Injection was the way to achieve these benefits, but although I found plenty of companies who 'talked the talk' on
this matter, I couldn't actually find any who were 'walking the walk'.
Lots of interesting info... LINKY
It's Evolution Baby!
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jabbahutt
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| posted on 9/4/10 at 08:54 AM |
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Another problem is LPG is cheap at the moment because not many people use it. Remember what happened with diesel, it started out cheap but as more
people switched to it to get the better mpg it miraculously went up in price and is now more expensive than unleaded.
Whatever becomes the norm the government will tax the hell out of it. Can't wait to see what a litre of hydrogen will cost if cars like the
Honda become the norm as the government would have to make up all the road tax it's loosing out on as they'd be tax free due to zero
emissions.
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trextr7monkey
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| posted on 9/4/10 at 08:57 AM |
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Hi there is a guy near Stafford who used to install LPG fuel systems for a living and also to his hobby vehicles very successfully, he had a couple
of Jago Jeeps- his brother ran one with petrol tank and lpg which was fine.
He then extrapolated the idea and did have a jeep running entirely on lpg.
His main problem was not of a technical nature but back to the buraucrats who apparently still wanted car excise duty as the system did not recognise
a car solely fuelled by lpg!
Could probably dig out his details if you wanted to kick ideas around with him, he ha snow moved on to Boom Trike 
atb
Mike
http://www.flickr.com/photos/14016102@N00/ (cut and paste this dodgey link)
Our most recent pics are here:
http://s129.photobucket.com/albums/p211/trextr7monkey/
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scootz
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| posted on 9/4/10 at 08:59 AM |
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If LPG was going to 'catch-on' as the fuel of choice, then it would have done so by now! AFAIK, none of the major manufacturers are
putting much research into the use of it just now.
It's Evolution Baby!
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richardlee237
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| posted on 9/4/10 at 09:04 AM |
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Mountune are supplying an LPG fuelled engine for the AON Fiesta in this years BTCC,
Reckoned to be the most powerful engine on the grid.
If you only fuel with LPG you can optimise the compression ratio.
Re liquifaction in winter could be overcome with careful air flow design and if necessary a preheater.
Quote Lord Kelvin
Large increases in cost with questionable increases in performance can be tolerated only in race horses and women.
Quote Richard Lee
"and cars"
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se7en
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| posted on 9/4/10 at 10:31 AM |
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I ran LPG in my Mercedes for about 4 years before I sold the MB.
There are basically two systems - Single point and Multi point. The Multi point system behaves just like a petrol injection system. It needs the
engine to be warm before it automatically switches over to gas.
The Single point system releases gas into the carb/air intake. It can start on gas but it is preferable if the engine is started on petrol and
switched over when the engine is warm. This system can be switched over quicker than the Multi point system.
There is quite a lot of information on the Tinsley Tech site and you can purchase your system
here.
Using gas, as previous stated, does not give you as many MPG - roughly about 90% of petrol. As an up-side LPG will give you better response (quicker
acceleration) and it is more GREEN friendly and it is cheaper than petrol. My LPG company has just written to me advising that the price of LPG is
going up by 2.5p per ltr; that's on top of another 2p rise in January.
Hope this helps
Tom
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rich201283
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| posted on 9/4/10 at 10:54 AM |
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I have installed both the single point systems and the sequential systems, The sequential system is the best to install and setup, i run the Marrrelli
system on a RR p38 4.9 and have had no problems with it.
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tomprescott
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| posted on 9/4/10 at 11:16 AM |
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I would suggest however, that although you can run solely on lpg it would be better for a small tank, because as stated above it will aid cold startsw
but more importantly, it will be easier to IVA your kit with a petrol tank than a gas tank! IVA it with petrol and then add lpg after!
A bird in the hand....
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big-vee-twin
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| posted on 9/4/10 at 11:41 AM |
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Saab and Subaru offer LPG cars now, I've been running my R26 on gas for 18 months very happy, however LPG has less octane than petrol so
performance suffors slightly, that is why you get less MPG on gas.
Most systems need to warm up on petrol too before they switch over, so a small petrol tank and larger gas tank would do it - don't forget you
can't go on the channel tunnel once converted.
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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britishtrident
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| posted on 9/4/10 at 11:46 AM |
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You can't run on LPG alone unless you go for the much more expensive liquid injection system.
There are really 4 different systems
(1) Mixer systems --- equivalent gas carburettor
(2) Single point vapour injection
(3) Multipoint vapour injection
(4) Liquid phase LPG injection ---
With modern engines particularly those with plastic inlet manifolds only types (3) and (4) are really viable.
It is possible to cold start a car with a multipoint injection on gas in moderate weather conditions BUT it really isn't good for the system as
the gas injectors will suffer from excess wear and the engine would need to idle for long enough to warm up properly before being driven. Ideally
the coolant temperature should reach at least 40c before switching to LPG.
Cold starting on lpg in near zero temperatures isn't possible without pre-warming the engine coolant with a pre-heater such as a Kenlowe
Hotstart.
[I] What use our work, Bennet, if we cannot care for those we love? .
― From BBC TV/Amazon's Ripper Street.
[/I]
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scootz
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| posted on 9/4/10 at 11:51 AM |
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quote:
Originally posted by big-vee-twin
however LPG has less octane than petrol.
You've got that the wrong way round... LPG has a higher octane rating that petrol!
It's Evolution Baby!
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scootz
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| posted on 9/4/10 at 11:52 AM |
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quote:
Originally posted by britishtrident
You can't run on LPG alone unless you go for the much more expensive liquid injection system.
There are really 4 different systems
(1) Mixer systems --- equivalent gas carburettor
(2) Single point vapour injection
(3) Multipoint vapour injection
(4) Liquid phase LPG injection ---
With modern engines particularly those with plastic inlet manifolds only types (3) and (4) are really viable.
It is possible to cold start a car with a multipoint injection on gas in moderate weather conditions BUT it really isn't good for the system as
the gas injectors will suffer from excess wear and the engine would need to idle for long enough to warm up properly before being driven. Ideally
the coolant temperature should reach at least 40c before switching to LPG.
Cold starting on lpg in near zero temperatures isn't possible without pre-warming the engine coolant with a pre-heater such as a Kenlowe
Hotstart.
Has there been any advance on the Liquid Phase Injection process... like I said, last time I looked into it there were a few Italian companies talking
about it, but none actually had any products out there...
It's Evolution Baby!
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britishtrident
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| posted on 9/4/10 at 11:54 AM |
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quote:
Originally posted by big-vee-twin
Saab and Subaru offer LPG cars now, I've been running my R26 on gas for 18 months very happy, however LPG has less octane than petrol so
performance suffors slightly, that is why you get less MPG on gas.
Most systems need to warm up on petrol too before they switch over, so a small petrol tank and larger gas tank would do it - don't forget you
can't go on the channel tunnel once converted.
LPG has a much higher octane than unleaded petrol higher even than good old 5 star petrol of the 1960/70s but it has a lower calorific value and
the volume gas vapour displaces some 6 to 7% of the air charge entering the cylinder.
The result of this around a 10% power loss with the current multipoint LPG vapour injection systems, this is one of the reasons Liquid LPG injection
systems have been developed.
Some of power loss can be regained by using more ignition advance black boxes can be fiited to give more ignition advance when running on LPG.
see http://www.ac.com.pl/wariatory/tap-02-wariator-kata-wyprzedzenia-zaplonu,97/
[I] What use our work, Bennet, if we cannot care for those we love? .
― From BBC TV/Amazon's Ripper Street.
[/I]
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britishtrident
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| posted on 9/4/10 at 11:57 AM |
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quote:
Originally posted by scootz
Has there been any advance on the Liquid Phase Injection process... like I said, last time I looked into it there were a few Italian companies talking
about it, but none actually had any products out there...
There are a couple of systems on the market I don't know the manufacturers name , ISTR it seems to be gaining ground in Australia. Most of
the conversion industry thinks it is the way to go as vapour injection has its' drawbacks.
[I] What use our work, Bennet, if we cannot care for those we love? .
― From BBC TV/Amazon's Ripper Street.
[/I]
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scootz
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| posted on 9/4/10 at 11:59 AM |
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Cheers... think I might re-ignite (see what I did there!) my interest in that one!
It's Evolution Baby!
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tomprescott
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| posted on 9/4/10 at 12:10 PM |
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quote:
Originally posted by scootz
Cheers... think I might re-ignite (see what I did there!) my interest in that one!
Oh dear
A bird in the hand....
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big-vee-twin
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| posted on 9/4/10 at 12:21 PM |
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Sorry - calorific value not octane, does do less to the gallon though
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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se7en
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| posted on 9/4/10 at 01:33 PM |
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quote:
Originally posted by big-vee-twin
... however LPG has less octane than petrol so performance suffors slightly, that is why you get less MPG on gas.
LPG has a HIGHER octane than petrol, thus as I stated above the performance is much better.
This performance has been shown in BTCC where the Ford Focus's that are running LPG get 5MPH faster down the straights.
Hope this helps
Tom
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dhutch
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| posted on 9/4/10 at 01:46 PM |
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Having been in the situation more than once of being in the middle of know where on a sunny sunday afternoon hoping to hell that there was an open
garage around the corner as the fuel gauge goes through the solid section of 'E' and on to the point where it doesnt even flicker under
braking and ive then put 26l into a 25l tank. Im more than happy with not having to find somewhere doing autogas!
Daniel
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britishtrident
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| posted on 9/4/10 at 02:31 PM |
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quote:
Originally posted by se7en
quote:
Originally posted by big-vee-twin
... however LPG has less octane than petrol so performance suffors slightly, that is why you get less MPG on gas.
LPG has a HIGHER octane than petrol, thus as I stated above the performance is much better.
This performance has been shown in BTCC where the Ford Focus's that are running LPG get 5MPH faster down the straights.
Hope this helps
Tom
Not in the the real world where you have to run dual fuel, in the real world with vapour injection power output is 10% down, if you want to take
advantage of the extra octane rating of gas you have to use a higher compression ratio and map more ignition advance. While the iginition map
isn't a problem the high compression ratio is.
With vapour injection because LPG vapour occupies much more volume than liquid petrol droplets you still have the problem that with compared with
an other wise identical petrol engiine an LPG fueled engine gets roughly 6% less air into the cylinders on every induction stroke.
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britishtrident
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| posted on 9/4/10 at 02:45 PM |
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quote:
Originally posted by dhutch
Having been in the situation more than once of being in the middle of know where on a sunny sunday afternoon hoping to hell that there was an open
garage around the corner as the fuel gauge goes through the solid section of 'E' and on to the point where it doesnt even flicker under
braking and ive then put 26l into a 25l tank. Im more than happy with not having to find somewhere doing autogas!
Daniel
Look at it this way it is twice as hard to run out of fuel on an LPG car because any LPG car on the road is dual fuel, you have to drain both LPg and
petrol tanks dry.
[I] What use our work, Bennet, if we cannot care for those we love? .
― From BBC TV/Amazon's Ripper Street.
[/I]
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mark chandler
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| posted on 9/4/10 at 04:21 PM |
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I ran a p38 ranger over on LPG, when the fuel pump went wrong I just played around with the changeover switch and started on LPG for a few weeks and
it was cold.
Just started, left idling for a minute then off I went.
OMVL sequential LPG.
I turned the change over to 25degrees C, it used to switch within a few hundred yards in the summer anyway.
I ran the vaporiser warming pipes in line with the heater hose instead of parallel so it got full flow of water.
Regards Mark
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