LPG for shiters

[cros]

Some interesting replies here. My orange car must rank as a poor choice for conversion- as Junkman points out LPG works best with higher compression and a different timing curve so the archaic B series isn't the best place to start- 26 mpg from a one ton car is pitiful. I wondered about putting a modern engine in that would give me mappable ignition, maybe the Mazda lump. Then I noticed that the MX5 comes with one already fitted so that would be silly.

 

I spoke to a bloke at the pump who was filling his newish C1 with LPG. He did a huge annual mileage paid by the mile and this thing cost the equivalent of 100mpg on petrol to run. No hybrid could get close yet you rarely see small modern cars converted.

[Des]

Junkman has hammered a socket over the head of the nail. When petrol went all Marlboro Lights with the removal of lead, LPG was the logical progression, but instead in this ridiculous world of fools the diesel has wiped its dirty claggy arse all over us.

I've built an RV8 with gas in mind, a general tidy and bacon slicered the heads to get CR up to snuff, weakened the bobweight springs in the dizzy, resulted in car that goes better on the funky stuff, even though it has standard airbox and not a single ebay performance chip or blue led anywhere. Obviously this is absolute heresay as I don't have any kind of dyno printout.

I'd love to play with LPG on something turbo, I reckon the boost could be turned up somewhere headbolt endangering.

[Junkman]

You'll need biiiiig throttle bodies for that. Lots of them.

[mat_the_cat]

I spoke to a bloke at the pump who was filling his newish C1 with LPG. He did a huge annual mileage paid by the mile and this thing cost the equivalent of 100mpg on petrol to run. No hybrid could get close yet you rarely see small modern cars converted.

 

People often don't do high miles in a small car, plus overall fuel used is lower so longer payback times for a gas conversion. Something which seems to be forgotten when spending several £k more to get a new shopping car which does 3 mpg more...

 

I've often wondered about the idea of a switachable supercharger, to get the CR up when running on gas. Best of both worlds? It can get very annoying trying to find somewhere selling LPG occasionally, so around here at least the idea of a gas only car wouldn't work for me.

[brickwall]

Many early vehicles were gas powered as JM says, but the practicalities were nuts. Transportation was indeed difficult and the vehicles themselves had to have a 'bag' instead of a tank. They came back into fashion during WWII for buses and vans that used coal gas with a huge bag on the roof. Some buses even towed a wood gas trailer to help power them.

 

 

[forddeliveryboy]

Saab made a car optimised for running on gas - it went faster and was more economical on the stuff. Even diesels love the stuff, you use tickover-quantities of oil to ignite the mix. As JM says, using liquid fuels in a gas engine is totally daft from a practical pov.

 

If you don't shit enough to run your car (you won't - you need a herd of cows), just put the garden waste into a bin, light it and put the lid on. Tap off the gas and your engine will run on it. Vietnam's buses did this until late in the last century, the driver lit the fire at the back of the bus, then lit a fag and waited. When the gas coming from the brazier bin ignited into a blue flame, off it trundled.

 

I quite like the idea of running low of fuel and just gathering a few more sticks together to throw on the fire.

[anonymous user]

I've had a Discovery converted to run on LPG, sadly despite it being an expensive (at the time) conversion, it never ran properly again on either LPG or petrol. It does seem to be down to not just the kit, but the installer.

I have a friend who is a great advocate for LPG, who takes the time to work it all out properly and does his own installations - he currently has converted his Lexus RX400h to LPG, (does that make it a tribrid?) I don't think he did it for reasons of economy, but more to see if he could.

[cros]

Junkman has hammered a socket over the head of the nail. When petrol went all Marlboro Lights with the removal of lead, LPG was the logical progression, but instead in this ridiculous world of fools the diesel has wiped its dirty claggy arse all over us.

I've built an RV8 with gas in mind, a general tidy and bacon slicered the heads to get CR up to snuff, weakened the bobweight springs in the dizzy, resulted in car that goes better on the funky stuff, even though it has standard airbox and not a single ebay performance chip or blue led anywhere. Obviously this is absolute heresay as I don't have any kind of dyno printout.

I'd love to play with LPG on something turbo, I reckon the boost could be turned up somewhere headbolt endangering.

Good choice. Am I right in thinking that the V8 weighs about the same as a b series just to add insult to injury?

[Des]

I Reckon they're about the same, RV8 is a big old two headed beast of a thing but made from monkey metal so nice and light, although if you're going to sack off the glorious B series why not play with it first. I'd be tempted to hang a turbo off it, knocking up a manifold from scaffold pole would be easy enough, fuelling should be a challenge but I wonder if a suck through setup, while not ideal for pez, would work well with gas, the 'Blos' mixer is a nice thing and could be rubber pipe hose clipped right onto the turbo, looks a bit like an SU carb as well, hammer one of those naff chrome dashpot covers over it and only yourself will know your dirty secret. Ignition timing might be tricky, I suppose blocking off the vac advance and closing up the plug gaps a tad might do.

[sheffcortinacentre]

lpg is ideal in forced induction engs.

[Clanger]

Anyone have any experience of CNG? I seem to remember Volvo bringing CNG cars into the UK a few years ago, but it didn't take off. Since there's a supply network already piped around the country and in future excess renrewable energy will probably be turned into gas and introduced into the pipes, this would seem to make sense.

I can't really give you any insight into CNG use in the UK, but I can tell you about my experience with it here on the sunny left coast.

 

I have been using a CNG Ford Crown Victoria as my daily driver for the last 15 years - my current Crown Vic I got nearly new in 2002 - it had 777 miles on the clock when it was delivered, it now has 139,839.  I won't get rid of it until it goes bang, which can be up to 450,000 if you play your cards right on these 4.6 V8s.

 

I sold my previous car with over 200,000 on the clock and I used to see it around for a few years after - I don't drive nearly as much as I used to so for all I know it could still be out there.

 

I toyed with the idea of getting a fueling station at home, but have given up on that idea a long time ago due to cost - plus, I have two commercial stations within a 3 mile drive of my house. 

 

Gas is currently about $3.69 per US gallon and CNG at my preferred station is $2.22 for a Gas Gallon Equivalent (GGE) - it has remained fairly stable for the last several years.  My favourite place to fill is out in Riverside county at the County yard as it's only about $1.50 or so for a GGE.  May car routinely gets around 18 MPG in mixed driving, with 25+ MPG on a nice freeway run.  I have the extended range fuel tanks, so less room in the boot, but an extra 2.5 gallons of fuel.  I had a regular gasoline Crown Vic before the two CNG cars and the MPG is somewhat similar, range is obviously better and filling stations are far more plentiful.

 

I think I can theoretically carry 12 gallons.  You will likely never get a "full" tank at a commercial quick-fill station as you lose somewhere in the region of 10% of your capacity because the gas expands due to the rapid transfer.  My longest drive between fill ups was on a trip from San Francisco back home to Orange County - I stopped at a place called Los Banos and filled my tanks, 307 miles later I rolled into my home station and took on 10.855 GGE - a touch under 29 MPG.  I cruised most of the way at around 80, except for the last 10 miles or so with the fuel light on.

 

My wife drives a nasty thirsty V8 powered VeeDub - she does half the miles I do and it costs us over twice as much to fuel her motor up.

 

As my car is dedicated CNG I have had to adapt to the reduced availability of refueling locations, but 15 years on and you would have to pry my CNG Crown Vic from my cold dead hands - I will run it till it dies, and probably beyond.

[Taff]

What’s a ball-park figure for a conversion kit? £500? £1000? £5000?

 

I quite fancy the idea of an LPG conversion on the MGF, I’m currently doing circa 1500 miles a month so any opportunity to drive down my fuel costs is appealing.

 

My google-fu tells me that a chap in Germany has converted his (it’s only a K-series after all, so the technology to convert the engine is out there), but the great big fuck off tank in the boot has taken away all his useable boot space (which the F isn’t exactly blessed with in the first place).

 

That said, it would then be a gamble to see if I can recoup my outlay before I get the OMGHGF feeling.

[cros]

There is UK MGF out there on LPG- I read about it a few years ago. The owner was happy with it, though as you say, not a lot of room for the tank.

[KruJoe]

I'd be willing to bet you could convert an MGF to XUD-Turbo'd-veg-munching-megalolz using a tuned 306 donor, and maybe some odd bits from an old R8 218D.

[Des]

If you're converting the MGF yourself it's suprisingly cheap, last thing I did was about £100 a pop for the vapouriser and mixer but they were a bit fancy and ones at half the price would have done, tanks are cheap if you go for a big ignorant donkey cylinder it's £80-ish, multivalve for it about £40, then pipings, plumbings and electric bits would be another £100. That makes up a very basic system, pays for itself in weeks rather than years, MGF probably merits a modern injection system, so a few hundred more, allegedly better economy and performance, abeit a whole world of complexity the like of which no sane person would entertain.

I've seen Chinese kits advertised for buttons, could be an interesting way to take out countless kittens on a budget.

[gordonbennet]

Ball park figure for conversions.

 

Outback cost £1350 last year (more than the car cost), but remember that's a six cyl (so more injectors etc) included an electronic flashlube kit.

 

A 4 pot system should be around £1000 to £1200 incl standard vacuum flashlube, you can find cheaper but choosing the right installer is the most important decision here, they are not all the same, some fly by nights start up then vanish so your two year warranty is void.

 

Beware anyone who reckons they can fit it all in a day, run like fook.

 

Worth checking out lpgforum.co.uk

[lisbon_road]

I have met a Polish installer who says he can do it in a day - with three men - and quotes £800 for a 4 cylinder car.  Very difficult - Polish lpg stuff seems ok, and I suspect that Polish installers can be very good but are they all good?  I don't know.

 

Tempted to convert my Mk3 Astra.  Have run lpg cars before and my wife has an lpg Zafira, so I am a total convert.  Seems to me it would really help with all the air quality fuss we have these days.  Why aren't more people advocating it when there is a network of garages all over?

[Alan_Green]

Had a quick search on Autotrader.NL  Looks like it might still be worth bringing LPGs over. £1,750 for a 2006. Is that really a 2006?:  http://www.autotrader.nl/auto/subaru-legacy/2006/arnhem/6mb6m/subaru-legacy-touring-wagon-touring-wagon-20-gl-aw/?zoekopdracht=subaru%7Csorteer-op-prijsvolgorde-en-prijs&trefwoord=lpg 

[KruJoe]

Is it really worth it?

That's probably only an £800 car over here.

[gordonbennet]

A Polish storeman who i got on really well with at one of my regular deliveries took his Mazda 6 V6 home when he went on holiday to see his family last year and got it LPG'd whilst there, cost him £500 inc flashlube (would cost about £1200/£1500 here)....very tempting but a sodding long way to go if it packs up.

[320touring]

A Polish storeman who i got on really well with at one of my regular deliveries took his Mazda 6 V6 home when he went on holiday to see his family last year and got it LPG'd whilst there, cost him £500 inc flashlube (would cost about £1200/£1500 here)....very tempting but a sodding long way to go if it packs up.

Done Riga to Glasgow via Poland in 2 days-no that far;)

[lisbon_road]

Well I met a Polish man who has set up in Bournemouth.  So he probably costs more than back in Poland but a lot less than the competition over here.  I must admit I am tempted.  Would like to do it myself, have done a couple before, but it would take me ages.

[lisbon_road]

I am now booked in for Friday for an lpg conversion with a local Polish man.  ACSTAG conversion £800.  He said all the right things - including that it might take two days as he might needs parts of whatever.

 

I will put on here how it goes........

[mat_the_cat]

Stag has the benefit of being capable of running most types of injectors (although with it being a budget system, is often bundled with the cheapest). So if and when the injectors fail, you're not tied into one make. Plus the software is widely available, either for DIY tinkering or ease of finding an installer who has it - unlike Prins or BRC for example.

 

I'd say that with enough people working on it, it could be done in a day; but are you going to get the best job when you're up against the clock and something goes wrong? And how do they check the changeover on a cold morning? (Maybe they set the changeover temperature on the high /safe side, leaving you running on petrol for longer than ideal). Time spent on mapping IMO makes the difference between a seamless conversion, and one which runs almost as good on gas, but maybe throws the EML light on now and again...

[panhard65]

I am now booked in for Friday for an lpg conversion with a local Polish man.  ACSTAG conversion £800.  He said all the right things - including that it might take two days as he might needs parts of whatever.

 

I will put on here how it goes........

If the chap does a good job could you ask him what sort of money he would want to do Rolls Royce silver spirit running on carbs 6 3/4 litre. Does he also supply a certificate for the insurance.

[sloth]

guys google gas research throttle bodys. designed for use on turbo cars. lots of nissan rb30's here in oz with them. 

[Asimo]

I would like to understand this "start on petrol, changeover when warmed up" business. What is the point?

 

Gas forklifts (for example) start on LPG perfectly ok.  I have been told that these Hong Kong Toyota Crown Taxis don't have petrol  for starting.

 

**

 

 

I would have thought that starting would be much easier on a gas / air mix than with a petrol / air mix.

No problems of poor atomisation due to low temperature, low velocity through carb., petrol vapour condensing out on cold combustion chamber & manifold walls etc.

 

Is it just done so that the convertors can get away with half a job, ie no engine temperature related mixture adjustment? Can anyone point me to a webpage discussing this?

 

Want to understand!

 

**I have had a lot of rides in these Crown Taxis, they are a real throwback but, of course, I have day-dreamed about bringing one back.  

[lisbon_road]

He does not supply UK certification.  I have to arrange that though he suggested a garage to do it.  

 

I can ask about the Rolls Royce.  He had a Bentley in there when I was there which he had converted and a massive Merc and a Jaguar outside, all relatively new.

 

Like I said, he said it might take two days........though with three of them there and such a simple car, I can't see why a day isn't possible, he just said it was better to err on the cautious side in case they have any problems.  By the way, he would be removing the inlet manifold.

 

He showed me a Polish lpg connector which is tiny and would be really neat.  I won't go for that, but interesting as would allow the connector to fit under the petrol cap.

[lisbon_road]

Just read that question about starting.  I think that it is emission based, as the gas system really struggles to get the mixture right when starting.  The theory is that the petrol system will be more accurate when cold as the petrol is incompressible where the gas varies in density so much when cold that emissions can be out.

 

Having said that, older systems can start on gas.  I ran my Ford Sierra for years on an AEB Leonardo system which I installed which had no petrol system at all.  

 

I would have thought that with an older car the petrol emissions on start up are probably dreadful anyway.

 

The installer did say that he can vary the switch over temperature and would set it for 35 degrees c, which won't take long to achieve.  

 

Aside, I've been to the factory where they make those Taxis in Nagoya Japan.  Amazing to see the workers rushing about.  Not a high volume factory so not the most technically advanced.  Mind that was ten years ago, perhaps a bit more.  I'm getting old!

[gordonbennet]

He does not supply UK certification.  I have to arrange that though he suggested a garage to do it.  

 

He showed me a Polish lpg connector which is tiny and would be really neat.  I won't go for that, but interesting as would allow the connector to fit under the petrol cap.

 

That concerns me a little, how much is certification going to be, is it a mate of his or an independent LPG installer with a reputation to maintain.

 

I like the continental connectors, had a chat with a nice Polish girl filling her car up at Morrisons, lovely neat little (so was the LPG point) filler point as you say tucked away beside the petrol filler under the flap.