Could any kind souls englighten me on the differences between LPG & NGV please?

Many of the thais told me that both will cause the engine to deteriorate greatly?

How is this so?

If so, i see large amount of people installing NGV onto their cars (brand new cars too!!)

There are two types of natural gas to fuel vehicles, Liquid Petroleum Gas (LPG, aka Propane) and Compressed Natural Gas (CNG) also refered to as NGV (Natural Gas for Vehicles).

WHAT IS CNG?

Compressed natural gas (CNG) is natural gas pressurized and stored in welding bottle-like tanks at pressures up to 3,600 psig. Typically, it is same composition of the local "pipeline" gas, with some of the water removed. CNG and LNG are both delivered to the engines as low pressure vapor (ounces to 300 psig). CNG is often misrepresented as the only form natural gas can be used as vehicle fuel. LNG can be used to make CNG. This process requires much less capital intensive equipment and about 15% of the operating and maintenance costs.

WHAT IS LPG?

Liquid petroleum gas (LPG, and sometimes called propane) is often confused with LNG and vice versa. They are not the same and the differences are significant. LPG is composed primarily of propane (upwards to 95%) and smaller quantities of butane. LPG can be stored as a liquid in tanks by applying pressure alone. LPG is the "bottled gas" often found under BBQ grills. LPG has been used as fuel in light duty vehicles for many years.

As to engine damage. Properly converted PETROL engines can run quite happily on either gas, some users note that the engine actually runs smoother on gas.

DIESEL engines are a different proposition as they cannot run on pure gas, the diesel still needs to be injected (in a smaller quantity) in order to initiate combustion. BMTA (Bangkok Mass Transit) and SRT (State Railways of Thailand) have both had bad experiences with converted engines failing rapidly. Mainly due to the engines being old to start with and the gas system not being correctly adjusted to the varying quality of the gas.

EDIT LNG = Liquified Natural Gas, not used in vehicles but as a means of transporting natual gas by sea, very cold and high pressure.

Edited July 1, 200619 yr by Crossy

Eventhough the Thai government is heavily promoting the use of NGV, to me it seems that LPG is a much more sensible choice...

As posted above, petrol engines have no problems running on LPG, nor will they deteriorate faster.

I've seen LPG cars happily chug away with more then 300,000km on the clock (most Taxi's in Bkk, every single one running on LPG!)

Main difference between LPG and NGV (the Thai name for CNG) is the way the gas is stored. LPG is stored at a relative low pressure (30 kg/sq cm) while NGV is stored at a whopping 200 kg/sq cm...

Obviously the NGV tank has to be much stronger, and weighs in emty at around 65kg!!! Ever tried dropping in a 65 kg weight in the trunk of your car??? Capacity of NGV tanks is limited as well, making the range a little over 200km for a small car (like the corolla's etc), but for bigger engines this can get as low as 180km between fill ups... Pretty annoying with not much NGV pumps around!

My gas guzzling 23 yr old Volvo runs happily over 350km on the standard 58 liter LPG tank (a cool 500 Baht to fill 'er up)

NGV fuel stations are far and between outside Bangkok (expensive equipment to install, remember the 200kg/sq cm) while there are quite a few LPG stations around in most provincial cities...

The obvious drawbacks are a small loss in power (10%), the space the gas tank occupates and no fill up stations out in the boonies...

But chugging along at 1.4 Baht/km compared to almost 4 Baht/km on petrol sure makes it worth for me, considering I drive around 30000 km/year!

How much does it cost to install CNG or LPG?

What is the size of the LPG gas tank?

Am i right to say that both CNG & LPG will suffer a 10% of power loss?

In Thailand the old style LPG systems (vacuum controlled vaporizer) will cost you some 10% loss in power (and 10% consumption increase in liter/100km). Installation between 15000 and 20000 Baht. Most common tank is 58 liter, but any size is possible depending on the space in your car...

The new style LPG systems (computer controlled multipoint injection) hardly give any loss in power, nor does the fuel consumption increases. Not sure about availability in Thailand but guess would cost between 30000 and 40000 Baht. Uses same tanks, so any size possible...

The 10% less consumption will make it take a very long time to recuperate the extra investment, and depending on the car the 10% powerloss is not really a problem. (apart from maybe an underpowered 20 year old toyota...)

NGV also has the standard vaporizer or computer controlled options, with same results on power output. Prices more expensive due to much heavier equipment (high pressure) and as far as I know only 1 size of tank available. (the 200km range tank).

Do note that with both systems you can always switch to regular petrol, so you can always keep driving until you find a gas station...

What is cooking gas? Could standard cylinders be used in vehicles? It is easy to find shops selling cooking gas. We take our empty tank and exchange it for a full tank. There are several place that do this even in a fairly small village.

One possible exception to the 'no damage' rule is if you have a car built in the pre-unleaded fuel days. The cooling characteristics of LPG differ from petrol and my understanding is that it can cause rapid erosion of valve seats and valves in older vehicles from the leaded gasoline era. The removal of lead from fuel required harder valves and valve seats so newer vehicles can use LPG without concern.

The solution is to install hardened seats and valves, e.g. stellite, if you have one of those older vehicles. For the vast majority of forum readers this will not be an issue, but for the few who have old vehicles like my Land Rover it is worth knowing. I plan on making the conversion at some point after locating and installing the hardened parts to the valve train.

The use of cooking gas cylinders is dangerous and prohibited by law. They are not as sturdy as the car cylinders and do not have the cut-off safety features either. Additionally, the cooking gas cylinder would not be permanently installed as are the car cylinders, which would add to possible danger in the event of an accident.

Edited July 2, 200619 yr by qualtrough

One possible exception to the 'no damage' rule is if you have a car built in the pre-unleaded fuel days. The cooling characteristics of LPG differ from petrol and my understanding is that it can cause rapid erosion of valve seats and valves in older vehicles from the leaded gasoline era. The removal of lead from fuel required harder valves and valve seats so newer vehicles can use LPG without concern.

The solution is to install hardened seats and valves, e.g. stellite, if you have one of those older vehicles. For the vast majority of forum readers this will not be an issue, but for the few who have old vehicles like my Land Rover it is worth knowing. I plan on making the conversion at some point after locating and installing the hardened parts to the valve train.

I am pretty sure the labour charges for stiffer valves would cost a bomb. Most of the locals here would not like to do anything to the engine, they would just drive the till engine give way & whoa la, they will then get a 'still in good shape engine' in.

I am thinking of getting a 93 to 94 Nissan Sunny (B14), then fix either a LPG or NGV......

I am pretty sure the labour charges for stiffer valves would cost a bomb. Most of the locals here would not like to do anything to the engine, they would just drive the till engine give way & whoa la, they will then get a 'still in good shape engine' in.

I am thinking of getting a 93 to 94 Nissan Sunny (B14), then fix either a LPG or NGV......

The labor would be peanuts. When I rebuilt the engine about 8 years ago the labor for boring the cylinders and doing a valve job was a couple thousand Baht at most. Later had the head milled .100" to bring it from 7:1 to 8:1 and that was so inconsequential I don't remember what I paid. Labor rates at machine shops here are about a 10th or less of what you would pay in the UK or the US. For me the pricy part if it could be called that would be the parts. For my old Rover the stellite parts would set me back about US$250. Not too bad, but about 5 times what the stock parts cost here. At the rate petrol is going I may just go ahead and have the LPG done and worry about the valves later.

Edited July 7, 200619 yr by qualtrough

Qualtrough,

I wouldn't worry to much about your valves, my Volvo (23 yrs old) also has the old style soft valves...

Basically all pre 1994 Volvo 240 and 740 series have the old valves (apart from the turbo versions who have hardened valves to withstand higher load/temperature) and they all drive on LPG in Thailand. Just go and fill up LPG and pretty much all you see is Volvo's and Taxi meters queing up

Also, they put in extra valve lubrication/cooling together with the LPG installation over here, which basically injects two stroke oil roughly at the rate of 1:300 (doesn't have to lubricate the whole engine like in a two stroke motor, hence the low rate)

It's probably not as good as hardened valves / seats, but goes a long way in extending the life of your parts...

Qualtrough,

I wouldn't worry to much about your valves, my Volvo (23 yrs old) also has the old style soft valves...

Basically all pre 1994 Volvo 240 and 740 series have the old valves (apart from the turbo versions who have hardened valves to withstand higher load/temperature) and they all drive on LPG in Thailand. Just go and fill up LPG and pretty much all you see is Volvo's and Taxi meters queing up

Also, they put in extra valve lubrication/cooling together with the LPG installation over here, which basically injects two stroke oil roughly at the rate of 1:300 (doesn't have to lubricate the whole engine like in a two stroke motor, hence the low rate)

It's probably not as good as hardened valves / seats, but goes a long way in extending the life of your parts...

Monty, thanks for the info. I will check out the lube injection. I may just go ahead and do it since the risk is only that the valve seats and valves will wear out prematurely. I have a complete spare set here anyway so even if that occurs it is not that big a deal.

I realized yesterday that LPG costs less than TEN baht..! (Eastern seaboard, this, I would imagine it being a bit more up-country)..

That's a HUGE difference.. How is that possible? And, isn't demand currenlty skyrocketing, inevitably leading to LPG prices catching up with regular fuels? Or is there some reason why LPG would always cost less?

Already now I notice big queues at LPG filling stations.. (Should I start an LPG filling station business I wonder? )

Also, after the conversion, the existing petrol tank remains usable right? So if you are somewhere where there's no LPG filling station, can you just go back to using regular petrol until you're back in a major town?

Cheers,

Chanchao

What is cooking gas? Could standard cylinders be used in vehicles? It is easy to find shops selling cooking gas. We take our empty tank and exchange it for a full tank. There are several place that do this even in a fairly small village.

GarryA LPG is very very safe when installed correctly - your thoughts of cooking gas cylinders would no doubt result in a quick exit from Loei back to Ohio via the ISS. In other words mate that would be a no no if you value your life. (ISS International Space Station).

I realized yesterday that LPG costs less than TEN baht..! (Eastern seaboard, this, I would imagine it being a bit more up-country)..

That's a HUGE difference.. How is that possible? And, isn't demand currenlty skyrocketing, inevitably leading to LPG prices catching up with regular fuels? Or is there some reason why LPG would always cost less?

Already now I notice big queues at LPG filling stations.. (Should I start an LPG filling station business I wonder? )

Also, after the conversion, the existing petrol tank remains usable right? So if you are somewhere where there's no LPG filling station, can you just go back to using regular petrol until you're back in a major town?

Cheers,

Chanchao

The gas tank remains usable. Most systems that I have seen here have a small switch that allows you to move between fuels. On some systems you start on regular gas (petrol) first and then switch to LPG, on others I believe you can start right up on LPG. The main point is you can shift between fuels without needing to stop the engine. I will leave it to the experts to elaborate on that or correct me if I am wrong.

As far as the price difference, I believe it is subsidized, but I have heard that even with the subsidy removed it would be cheaper than petrol. Anybody know the facts on this? I would hate to make the conversion and then find that a subsidy had been removed and now the price was the same as petrol!

I imagine the lines will get longer until the supply catches up. I bet the conversion outfits are getting all the work they can handle too, what with petrol rising almost every week.

Yep, you can freely switch between fuel and gas...

I start my car on fuel and then switch immediately to gas. It does start on gas, just needs a little bit more cranking, hence the fuel start. I reckon it's easier on the starter motor and battery.

My car has electronic fuel injection, so the switch between gas and fuel is immediate, if I recall correctly, with a carburator you have to run the fuel bowl empty first before you switch trough to gas (the switch has a middle position, where neither gas nor fuel is fed to the engine)

And yes, my local LPG installer is indeed pretty busy nowadays. There's a small que at the filling station, but I think they have 6 pumps so the wait is never long!

The gas is subsidized at the moment, but not very much. Without the subsidy it would go up to between 12 and 14 Baht/liter, still less then half of what regular fuel costs...

Edited July 12, 200619 yr by monty

LPG is a bi-product of oil extraction and also extracted where there are no oil reserves. In some places they dont even bother collecting it. The flame that you see coming from the drilling rigs is the LPG being burnt off.

The price is less expensive because it does not have to be refined in the same way that petrol does. Basically the cost is in containing it and transporting it. Also you dont have the huge taxes on LPG that you have on petrol in some countries.

Off Western Australia there is a project called "The Great North Western Shelf", which is the largest LPG production platform in the world. From here the LPG is transported in massive ships mainly to Japan and China where they pay less than 2c per litre so even though 9 baht per litre here sounds innexpensive, the companies are still making hefty profits.

There are many differant LPG systems that you can convert you car over too, but the tendancy seems to be going towards the system where you can run on either straight LPG, straight Petrol or you strart the engine on Petrol and there is a heat sensor in the engine that switches it over to LPG when the engine reaches a certain temperature as opposed to switching it over manualy.

Having said this, in taxis they generally start them on LPG all of the time and dont seem to have a lot of problems.

LPG is far more kinder to your engine and your engine will have a much longer life by using it.

With the 10% power loss that you get on LPG, what i usually do is if you need extra acceleration to pass a convoy of trucks or slow vehicles is just flick it over to petrol and then back to LPG once ive passed them.

The downside of using NGV instead of LPG is that it takes at least 20 minutes to fill your tank and there are fewer refilling stations.

Edited July 21, 200619 yr by COBBER

am i correct in thinking Thailand has its own reserves of natural gas in the gulf, which could mean that prices would not rise that much even if it wasn't subsidised?

I guess it depends on how much gas they have.

I realized yesterday that LPG costs less than TEN baht..! (Eastern seaboard, this, I would imagine it being a bit more up-country)..

That's a HUGE difference.. How is that possible? And, isn't demand currenlty skyrocketing, inevitably leading to LPG prices catching up with regular fuels? Or is there some reason why LPG would always cost less?

Already now I notice big queues at LPG filling stations.. (Should I start an LPG filling station business I wonder? )

Also, after the conversion, the existing petrol tank remains usable right? So if you are somewhere where there's no LPG filling station, can you just go back to using regular petrol until you're back in a major town?

Cheers,

Chanchao

The gas tank remains usable. Most systems that I have seen here have a small switch that allows you to move between fuels. On some systems you start on regular gas (petrol) first and then switch to LPG, on others I believe you can start right up on LPG. The main point is you can shift between fuels without needing to stop the engine. I will leave it to the experts to elaborate on that or correct me if I am wrong.

As far as the price difference, I believe it is subsidized, but I have heard that even with the subsidy removed it would be cheaper than petrol. Anybody know the facts on this? I would hate to make the conversion and then find that a subsidy had been removed and now the price was the same as petrol!

I imagine the lines will get longer until the supply catches up. I bet the conversion outfits are getting all the work they can handle too, what with petrol rising almost every week.

My wife has just had LPG installed in her 1995 Suzuki Caribian 4X4. Total costs for professional installation and manual crossover switch THB17,500.

We have 15 days to go to Land Transport Dept at Chatuchak and register the change.

I was wondering if any other readers here have had the conversion and is the operating / explanation brochure available in English also(or is that asking too much?) We live on Petkasem and there are 2 LPG stations right near Phayathai hospital.

Edited December 1, 200718 yr by ratcatcher

wow monty , thanks for detailed input.. Now you've made me pity Bkk cabbies.. As from what you've described, the savings are not that great ! See if you spend upto 40,000 baht on the installation & it only saves you a baht, or 2 per kilometer, not calculating, the loss of trunk space & extra weight++ if like me, when i drive away from Bangkok, the availibility of LPG, you might only start saving anything after a whooping 50,000km !! Well in the best case scenario (if only used in Bangkok) its probably somewhere around 2+,000 km. when your investment will materialise into any savings.. no wonder it isn't that popular

I finally got around to doing the LPG conversion for my old Land Rover several weeks ago. Cost 17,000 Baht and I had a 96 L tank installed, which holds 81 Litres. The power loss is minimal and for some reason I have actually gotten better mileage than I did before! My engine runs cooler and does not diesel on shut off as it was wont to do before. It also runs a bit smoother too. Another benefit is extended range with 81 Litres. Loving it so far, esp. when filling up! The installation will pay for itself in less than 4 months with the amount of driving I do and the crappy mileage I get.

A previous poster mentions having to take care of the LPG registration details within 15 days. I was told that I only had to do that the next time the annual registration expires. I will check that out and report back. If that is true I am not too worried as things like that usually have humongous fines like 100 Baht! I hope I don't have to eat those words.

P.S. The circular tanks that fit into the spare tire wells are now available here, though a bit more expensive. Conversion for our Volvo with a conventional tank was quoted at 17000 Baht, for a circular tank 25,000 Baht. Rated for 60+ litres, can't recall the exact figure.

Edited December 1, 200718 yr by qualtrough

You may want to reconsider an LPG conversion. All LPG in Thailand is domestic. If the conversions continue at the rate they have this year, LPG will have to be imported to meet the demand. The government is planning to slow the conversion rate by possibly adding a road tax and have already increased the price of LPG.

I've been running a 1994 Land Rover Discovery on LPG since April 2006, and haven't looked back since. I changed the engine to a Lexus 3 litre VVTi (2J) with automatic gear box all the same time, but kept the original Discovery 4 wheel drive transfer box. Total cost of engine and LPG conversion was 105, 000 baht. Done almost 40,000 km. since the conversion, and i get 6.00 - 7.00 km. per litre using LPG depending driving in town or on a long run. I have now already recovered the cost of the engine and LPG conversion, and now quids in.

Having driven south to Krabi and Phuket a number of times, more and more LPG stations are opening each time i go down. I think i've used abou 30 litres of gasoline since the conversion.

SO GO FOR IT.

You may want to reconsider an LPG conversion. All LPG in Thailand is domestic. If the conversions continue at the rate they have this year, LPG will have to be imported to meet the demand. The government is planning to slow the conversion rate by possibly adding a road tax and have already increased the price of LPG.

That is a possibility, but even if that occurs it would my understanding is that it would still be cheaper than gasoline. I think for political reasons that day is still far off. The price did increase recently by 80 satang/L. I can live with that.

i have been considering moving to either LPG or NGV for my Honda Civic 1.8. its still relatively new car (below one year) but i drive a lot and the prices for fuel is killing me. my brother in law drives an Audi 2.4 v6 and i worked out his mileage to be 2.3baht to a km. mine is 2.7 baht per km. i am sure with my car, i can do about 1.5-1.7baht to a km. that is still a good saving but doing it on a new car? what do you guys think? more worthwhile just to run on petrol?

NGV is out of the question cause, installation too expensive, too few filling stations in chiang mai, huge and heavy tank, too long of a wait to fill up. LPG seems perfect.

my main question: would u do it on a new car? LPG conversion. also can someone recommend a good professional installer here in chiang mai. the place my bro in law did doesnt seem very professional. then again it was an audi and had some problems initially. now its working alright.

Your vehicle is ideal to do a LPG conversion on .

It is generally recommended that an engine be run in before converting and have less than 100,000 k,s on the clock .

NGV seems to be getting a push in Thailand though , it may pay to do a bit of research as top whether it will become

available to you .

The other thing of course is how long do you intend to keep the vehicle , will a conversion pay for itself .

The price of fuel is a scary topic for me , it has doubled in price in Thailand in about five years , all things

being equal , it may well double in the next five years .

I might be looking to one of them three wheel bicycles as my retirement transport

i have been considering moving to either LPG or NGV for my Honda Civic 1.8. its still relatively new car (below one year) but i drive a lot and the prices for fuel is killing me. my brother in law drives an Audi 2.4 v6 and i worked out his mileage to be 2.3baht to a km. mine is 2.7 baht per km. i am sure with my car, i can do about 1.5-1.7baht to a km. that is still a good saving but doing it on a new car? what do you guys think? more worthwhile just to run on petrol?

NGV is out of the question cause, installation too expensive, too few filling stations in chiang mai, huge and heavy tank, too long of a wait to fill up. LPG seems perfect.

my main question: would u do it on a new car? LPG conversion. also can someone recommend a good professional installer here in chiang mai. the place my bro in law did doesnt seem very professional. then again it was an audi and had some problems initially. now its working alright.

I have been told that generally you can expect to save 60% on LPG here vs. Petrol. In my case I get a bit better than that. If you are getting 2.7 km now with petrol my calculation shows you would be spending 1.08 Baht per km. I am not a mathematician, so please check my math before doing anything serious.

I read an article that said that very soon any new taxi in Bangkok MUST use CNG as fuel. That may take the pressure off LPG and prevent the price from going up too much.

I read an article that said that very soon any new taxi in Bangkok MUST use CNG as fuel. That may take the pressure off LPG and prevent the price from going up too much.

but LPG is still petroleum. bound by market movements. unlike natural gas.

thats my only concern. no point investing in an LPG conversion if in the next year or so, the prices reach that of petrol.

I read an article that said that very soon any new taxi in Bangkok MUST use CNG as fuel. That may take the pressure off LPG and prevent the price from going up too much.

but LPG is still petroleum. bound by market movements. unlike natural gas.

thats my only concern. no point investing in an LPG conversion if in the next year or so, the prices reach that of petrol.

I recently read another article that said that all LPG used in Thailand is domestic. If the conversions continue at last years rate, within two years Thailand will have to import LPG. The government is trying to prevent that from happening so they are considering a road tax, eliminating the subsidy and have already raised the price. It apparently was a small increase because it said that the average cost for cooking gas went up 9 baht per year for a Thai household. I'd bet that a road tax will be added to protect the price of cooking gas.