LPG

[gords]

OK, so tell me all about LPG!

What is it / why is it so cheap?

Is it mixed with petrol or is it a case of petrol OR LPG?

What's "multi-point" and is it good/best? What's wrong with non "multi-point"?

Does LPG affect engine power or fuel consumption?

Anything else worth knowing about LPG?

[jjsaul]

OK, so tell me all about LPG!

What is it / why is it so cheap?

Is it mixed with petrol or is it a case of petrol OR LPG?

What's "multi-point" and is it good/best? What's wrong with non "multi-point"?

Does LPG affect engine power or fuel consumption?

Anything else worth knowing about LPG?

LPG is great.
It means we can afford to run V8's  :lol:

It's cheap because its a waste product of petrol production and tax is less cos its a greener fuel.

Multi point is better than single point as you dont suffer any power loss if its set up right. It is more expensive to fit though.

Single point there is a slight power drop from petrol, but not too bad tbh. Consumption is a bit worse but at 40pence a litre you cant really complain!

I've got 1 LPG rangie, an LPG 110 and an LPG vectra...and my other rangie is being converted when i get round to it....  :D

[Rich_P]

LPG burns slower than petrol (burns hotter too I think, anyone confirm?), so adjustment to the ignition timing is recommended.  You can either have it run rough on gas and have it run fine on petrol, or fine on gas and rough on petrol or a comprimise between the petrol and gas running states.  This of course largely applies to just manually timed engines.  No idea how engines like the EFi units handle it.

[v8kenny]

LPG is liquid petroleum gas and is a by product of petrol refining
It is so cheap cos the government don't tax it to the hilt ( yet ) as it's a cleaner burning and therefore greener fuel source
It is not mixed with petrol - you either run on gas or petrol fed to the engine from seperate tanks - this is usually a simple flick of a switch on the dash
multi pont is like fuel injection and is almost a must have for injected V8's for them to run properly - carb fed engines are more than happy with a single feed to each bank of cylinders via the inlet manifolds
engine power will be slightly down but to be honest not noticeable on a V8
fuel consumption will also be down a bit

Lpg can also be used on diesel engines but this is a mixture of diesel/gas at a ratio of about 10% gas AFAIK
I have had two V8's running on gas - a 110 3.9 V8 running on SU's and a 3.5  V8 Disco running a multi point injection system
Both ran really well and I maintain that V8's are even smoother on gas if set up correctly
V8 power and diesel equivalent economy - can't go wrong really
That's my humble opinion anyway

[gords]

Is it mixed with petrol or is it a case of petrol OR LPG?

How "available" is LPG, nationwide? How about Europe?

[v8kenny]

You can get up to date maps of filling stations that supply gas from go-autogas.com
I never found a problem travelling around the country with a little forward planning - doesn't matter about running out (apart from cost ) cos you can run on petrol till you can fill up again

[tomarse]

How "available" is LPG, nationwide? How about Europe?

i think most of europe is similar to here. France definately is.
Worth getting POI's in a tomtom if you do any serious driving anywhere (uk or europe) so you can plan to go via a garage.

[Skibum346]

The other thing of note about LPG systems on a efi V8 i sthe need for emulators to fool the ECU when on gas. These may just be required when using a single point system... I'm not sure.

Usually there is a need to give up some cargo space for an LPG tank... but there are lots of options to look at to minimise this problem. Don't let a fitter dictate to you the positioning... our 80 litre tank in the boot of an RRC was going to be parallel to the back seat... unitl I sked if it would fit fore & aft on the narrow side of the split rear seat. As a result we have an 80 litrs tank but can still take a dead body stretched out... should I ever get my way with the mother in law!

Skibum

[Rich_P]

The other thing of note about LPG systems on a efi V8 i sthe need for emulators to fool the ECU when on gas. These may just be required when using a single point system... I'm not sure.

Yes they're required.  Otherwise the EFi will still pump petrol into the cylinders when the single point LPG unit is operating!

[edy]

ye the tanks can be placed were you like (may lose a liter hear and ther) you can have the 80 litre  in the boot, dohnut tank were the spare wheel would go (under floor) and torpido tanks wich are mounted under the car. if you have multi point on say a v8 it also helps stop backfire when on gas.

every one has said everything that needs to be said realy,

gas is deffinetly the best option.

[gords]

So, do you run on LPG all the time unless / until you run out, at which point you switch back to petrol?

I assume the switching done manually?

What (typical) size are the LPG tanks? I've seen that Range Rovers can have them in the spare wheel hole - what size would they be? I've seen pictures of the tanks in the back of the boot (RR - against the back seats) and it seems to take up a huge amount of space!?

[barnhill4x4]

I have Multipoint in my p38 with an 88 litre tank in the spare wheel well.
  Starts on petrol then once warmed up a little automaticly switched to gas, mine does this once the coolant reaches 15degrees C. So it is on gas within a few hundred yards.
  I try to keep gas in the tank but on the odd occasion it runs out of gas it will automaticly switch over to petrol and beep at you to let you know. This also happens if you are low on gas and floor it, it will switch over to petrol and the only way you know this has happened is the beep. I can have my foot flat to the floor and switch from gas the petrol and back again without any loss of power you cant even feel anything as it changes over, its that smooth.
  Had mine fitted for £1350 all in locally

[hairyasswelder]

LPG ... I got a 90 ltr tank behind the seats (RR classic) it is full width and 360mm dia and takes up half the boot   but I can always use a roof rack.
Locally there are 6/7 stations with pumps
For different countries there is a different type of filler adapter so if travelling europe you will need these to fill up  
Performance is slightly affected but who cares when you are cruising down the motorway  :D
Mine starts on petrol and changes automatic to gas, when it runs out you just switch back to petrol   some expensive systems are fully automatic
try searching for 'tinleytech' for more ideas on tanks and prices

Steve

[Lucy1978]

Gas is generally available throughout Europe, all the way across eastern Europe through Turkey couldn't get any in Syria though, though it's not so popular in Germany, with very few stations and those that do sell it being way out of towns.

[gtomo2]

I have a 100 ltr tank (holds 80ltrs every tank has to have a 20%extra space for expansion of the gas). mounted in the back of my disco its a 3.5 efi runing single point and it runs just great. yes the switch over is a single littl push button switch. What you will find is the car will start on petrol then switch over automaticly to gas after acouple of secs. And it is just as cheap to run as my old diesel rangy. got the littl blue book that has all the lpg stations around the uk. but never had a problem with not finding somewere with lpg pump

[Range Rover Blues]

LPG is basically Propane, it's a by-product of refining Eurobox fule and burns more cleanly than petrol, so becasue it's waste that has to be burned and it's clean, it's a green fuel and taxed accordingly.

LPG may contane butane on the continent, this has the effect of increasing it's calorifice value closer to that of petrol.

Correct, it does burn hooter but slower, so it releases less power for a given swept volume (calorific value) but you can increase the ignition advance because LPG has an octane rating of around 115, the ideal compression ratio is around 11.5:1

On a single point you may well notice some drop in power, particulalry at either end of the rev-range where the fueling is not that good.  Some of the power can be regained by fitting an igbnition advance module, at around £110 from Chris Perfect, though I have found them cheaper by hunting around.
Inevitably the lower calorific value means lower MPG but our 3.9 on a draw-through single point can do 13mpg

On my multipoint I notice no drop in power, but it's a thirstly beast.  The ECU controlled fuelling is a better match to the petrol EFi system and this is where it scores.

Downside I can get it to do 9mpg with the BWSOW on and the Airconn
Upside, I don't care when it's 40 p/litre and it is a 5.0 TVR lump

Single point sytems can cause back fires, I got sick of sweeping up my air fliters so I fitted a K&N, these are backfire-resistant becasue they are built with a wire cage.
My multipoint cost £1250 and a couple of weekends to fit, I had the most expensive tank the upright torriodal (spare wheel).  A cheapo single point might be £350

LPG will make you engine cleaner inside, your oil will get less contaminated and the engine last longer as a result of both.

It may run quieter.

Because of the higher temp it is not adviseable to make an engine slog away in high gears, the lack of torque will discourage this anyway, but that high temp has been linked with porous block syndrome as well as some instances of cracked valve seats/springs, burned valves etc.
Your engine needs to be in top condition, I would also suggest adding a vbalve-saver kit to oil the valves, LPG is too dry.