Time To Convert My Car To Use Ngv/lpg

[Plus]

Most taxis run on NGV/CNG, not LPG, though there's a fair number of LPGs, too. Safety is not an issue, statistically speaking.

Poper LPG system in a modern engine cost nearly as much as CNG, or at least comparable while the price of CNG is significantly cheaper, and the gap will only grow.

The reason behind push of NGV is that it's Thai own natural gas while LPG is a petroleum product and needs to be imported. They worry about country's import bill, that's why all this bruhaha with gasohols and biofuels, and NGV, too.

LPG prices are set to rise, but politically it's a difficult move as the whole country cooks on LPG, and also the number of LPG converted cars and stations is growing very fast - too many people will be affected. It's probably cheaper to maintain low prices than deal with consequenses, especially with effects of expensive cooking gas.

[Thaiboxer]

I've always gone with the notion that it's best to stick with regular 91 gasoline. It's not cheap, but I would feel much safer with liquid gasoline back there than LPG.

[clausewitz]

Poper LPG system in a modern engine cost nearly as much as CNG, or at least comparable while the price of CNG is significantly cheaper, and the gap will only grow.

.

My lpg system cost 14,000 baht to install in December. I think NGV is around 50,000 to 60,000 baht for installation.

[mixed]

I've always gone with the notion that it's best to stick with regular 91 gasoline. It's not cheap, but I would feel much safer with liquid gasoline back there than LPG.

When it comes to driving in Thailand, I've never felt safe. In this context issues regarding the dangers of either gas are 'blown' out of proportion.

[Thaiboxer]

I see your point...the style of driving here is pretty frightening.

[tracker]

my situation:

20 year old benz, 5000cc with lpg, 75ltr tank. runs 7km on 1 ltr. Bought it 15 months ago, Have driven 20.000km since then.

safety:

there are 3 electric (solenoids) shutoff valves on my system: tank, vaporizer, and in between. The "in between" got a leak and when i replaced it myself, that one leaked too (local made brass or copper valve). So "safety" of 3 valves actually created a hazard. Another valve (also local) fixed it. My leak was simply detected by lpg smell in the car... No boom...

use:

offcourse driving a 5000cc car with lpg is fun. ok, it's slow compared to gasoline injection, but with todays prices, i'm doing 1.5 baht/km and that is a lot better than my 2500cc diesel truck which is 3.3 baht/km. And i even get a lot more comfort in the benz.

advice:

Getting people together and trying to get a lower price is asking for inferior work. Do not save money on this! Also you might want to choose the more expensive lpg injection (probably 35 - 40.000 baht) which does not lower the power of your car AND has the same mileage as running on gasoline (older constant vacuum inlet-manifold entry always uses more lpg (liters/km)) . So that will pay back to you very fast.

Edited May 16, 2008 by tracker

[Thaiboxer]

If your car has a carburetor like ours does, the entire fuel system would have to be reworked right? Perhaps that would cost more than what it cost to convert a fuel injected car.

[monty]

If your car has a carburetor like ours does, the entire fuel system would have to be reworked right? Perhaps that would cost more than what it cost to convert a fuel injected car.

Not true!

The only difference with a carburetor fed engine, is that when you switch from petrol to gas, you'll have to leave the switch in the middle stand (shutting down the fuel supply to your carburetor, but not yet allowing LPG to enter the system) until the float chamber of your carburetor runs empty.

When you feel your engine is going to stall, you switch over to LPG.

The other way around, it'll take a second for your fuel pump to fill up your carburetor before it will want to run on petrol again.

With a fuel injected car, the switch over is instantaneous.

[monty]

Most taxis run on NGV/CNG, not LPG, though there's a fair number of LPGs, too. Safety is not an issue, statistically speaking.

Poper LPG system in a modern engine cost nearly as much as CNG, or at least comparable while the price of CNG is significantly cheaper, and the gap will only grow.

I think the majority of the taxi's (and tuk tuks) still run on LPG, only the newer vehicles will be converted to NGV.

EFI controlled LPG systems cost around 35,000 Baht (4 cylinder) so still significantly cheaper!

As said many times, economically NGV is better, especially in the long run.

But the range is simply a killer!

At my work we have a Nissan Cefiro for airport pick ups, round trip from our resort to Suvanabhumi is 230 km, while the range of the Cefiro is around 170 km on an NGV tank.

Additionally it's another 15 km to the nearest NGV filling station (unfortunately exactly the opposite direction as Suvanabhumi).

By the time the car is back in the resort with a filled tank, only 155 km range remains.

In short, it's 170 km on NGV, followed by 75 km on petrol, of which 30 km is non revenue generating! This already works out to be 40% more expensive per km (due to the distance driven on petrol at 36 Baht/liter) compared to running the full distance on LPG.

Range on the currently fitted 90 liter (77 usable) LPG tank is over 600 km! With no detours needed to reach an LPG filling station, with hardly no cues either!

[Plus]

offcourse driving a 5000cc car with lpg is fun. ok, it's slow compared to gasoline injection, but with todays prices, i'm doing 1.5 baht/km

Excellent fuel consumption for a 20 year old 5l engine. Elsewhere people get that from six-seven years old 1jz that is only half the size. I get 2 baht/l on 2jz which sounds about right for the size and the weight and the fun. Once the shop detuned the engine to consume less LPG, but the drop in power was unbearable. Right now I think they've found a sweet spot for compromise, should be about 1.6-1.8 baht per litre but I woudln't bet on it when I go for refuel tomorow.

[Plus]

Everytime I ask a taxi drivers what they use, they say NGV. Taxis at LPG stations look quite old.

Cheap systems are not compatible with variable valve engines, sooner or later the engine will backfire.

In taxis they just use a rubber cord to hold air-filter together in case of an explosion.

35k for controlled injection kits are not that far from CNG system prices, not the same as 14k and 50k difference.

[monty]

NGV is the way to go...

If you can live with a 130 km range, which is what you'll get if you're currently burning 1.8 Baht/km!

IMO it is simply not practical, not even on a fuel efficient jazz or vios, and not even when you have loads of filling stations. I hate waiting to fill up, I love the 500 + km range on my LPG tank...

[tracker]

thaiboxer:

Yep, if you have carb, you should install only the non-inject version, which means the cheapest. Good for you

plus:

It is indeed a good mileage for the engine size, but there is a little story behind it:

On the outgoing line going from vaporizer to air-intake there is an adjustable valve. I played with it a bit, like turn it 90degrees clockwise, and see what effect it had on performance and mileage. I could turn it 270degrees more closed before getting any engine problems (like engine stops running while on low rpm). that brought up the mileage from an average of 6.5 to 7.0km per liter.

Another point is that the engine of this car is a replacement (was originally a 380se) and now has a 500se engine, So i do not know how many miles the engine has run, only that the engine was replaced 10 years ago.

Another important point is: after 20.000 - 30.000 km driving, I only added 1 liter of oil.

Everytime (monthly) when i check the oil, I still see the green/yellow colour of oil on the oilstick, meaning that the lpg use is very gentle on the engine.

[monty]

thaiboxer:

Yep, if you have carb, you should install only the non-inject version, which means the cheapest. Good for you

plus:

It is indeed a good mileage for the engine size, but there is a little story behind it:

On the outgoing line going from vaporizer to air-intake there is an adjustable valve. I played with it a bit, like turn it 90degrees clockwise, and see what effect it had on performance and mileage. I could turn it 270degrees more closed before getting any engine problems (like engine stops running while on low rpm). that brought up the mileage from an average of 6.5 to 7.0km per liter.

Another point is that the engine of this car is a replacement (was originally a 380se) and now has a 500se engine, So i do not know how many miles the engine has run, only that the engine was replaced 10 years ago.

Another important point is: after 20.000 - 30.000 km driving, I only added 1 liter of oil.

Everytime (monthly) when i check the oil, I still see the green/yellow colour of oil on the oilstick, meaning that the lpg use is very gentle on the engine.

LPG is indeed very gentle on the engine oil.

That mileage is brilliant, have the same engine here ('97 500 sec), I'm getting less then 5km to the liter (actually around 25 liter/100km or 4 km/liter) running on petrol, but this is with a lead right foot.

The normal procedure for tuning that valve you mention, is to rev the engine at 3000 rpm, and start closing that valve until you notice an RPM drop (without moving the throttle obviously).

Then just open the valve a tiny little bit.

Running the engine with that valve closed to much can be very bad, you'll run lean and combustion temperatures will get too high!

[Plus]

I don't have that screw, all controls are through the computer. I think I'll ask for the program and connectors so I can tune it myself, it is meant to be tuned by the customer, I understand.

1.5 baht/km is 7 km/l, nearly double what you get from your engine, Monty.

[Thaiboxer]

I get about 7km/liter in the city and 8km/liter on the highway with 91 gasoline. Yesterday, I paid over 1,600 Baht to fill the tank!

Like another poster mentioned about his engine, the engine I have (2.0 liter, pushrod, carburetor) is not original. The engine/transmission were taken from another vehicle and dropped into our car about 20 years ago. The original 1.8 liter engine simply wore out from all the driving. It rain on NGV or something similar and still has the valves under the hood/trunk. I have over 460,000km on the clock, so not sure how many of those km's are on the current engine. I would imagine it's quite a few though.

Has anyone ever replaced a carburetor and gotten better mileage? Perhaps simple replacements/adjustments to the fuel system may be cheaper than LPG conversion, plus it would provide decent mileage. Our car's body is old and has tons of rust around the bottom edges of the body so not sure if major LPG work would be good.

[INTJ]

Most taxis run on NGV/CNG, not LPG.

Incorrect. The cost of the conversion and the limited range mean the opposite is true.

Tracker :"my situation - 20 year old benz, 5000cc with lpg, 75ltr tank. runs 7km on 1 ltr.

Nice to see someone has got the same idea.

Cheers

Edited May 18, 2008 by INTJ

[Thaiboxer]

I've seen some Mercedes for sale with Toyota engines in them. That's always another option to consider as labor isn't too much and a secondhand diesel engine could fit in there nicely.

[INTJ]

Here's the engine bay of mine

[hans1977]

You should follow the instruction from monty on how to adjust the valve you've been playing with. If you have problems with the engine after that (it's stopping or not smooth), you should open the low speed valve (on the reducer) until the engine runs well.

/Hans

thaiboxer:

Yep, if you have carb, you should install only the non-inject version, which means the cheapest. Good for you

plus:

It is indeed a good mileage for the engine size, but there is a little story behind it:

On the outgoing line going from vaporizer to air-intake there is an adjustable valve. I played with it a bit, like turn it 90degrees clockwise, and see what effect it had on performance and mileage. I could turn it 270degrees more closed before getting any engine problems (like engine stops running while on low rpm). that brought up the mileage from an average of 6.5 to 7.0km per liter.

Another point is that the engine of this car is a replacement (was originally a 380se) and now has a 500se engine, So i do not know how many miles the engine has run, only that the engine was replaced 10 years ago.

Another important point is: after 20.000 - 30.000 km driving, I only added 1 liter of oil.

Everytime (monthly) when i check the oil, I still see the green/yellow colour of oil on the oilstick, meaning that the lpg use is very gentle on the engine.

[hans1977]

What kind of ignition do you have? I have the old style system with points and capacitor, but have now fitted an electronic drive to the ignition coil. That did a lot to the performance on gas, but not so much to the performance on petrol. Thus, i would say the performance is now more or less the same for gas and petrol.

/Hans

my situation:

20 year old benz, 5000cc with lpg, 75ltr tank. runs 7km on 1 ltr. Bought it 15 months ago, Have driven 20.000km since then.

safety:

there are 3 electric (solenoids) shutoff valves on my system: tank, vaporizer, and in between. The "in between" got a leak and when i replaced it myself, that one leaked too (local made brass or copper valve). So "safety" of 3 valves actually created a hazard. Another valve (also local) fixed it. My leak was simply detected by lpg smell in the car... No boom...

use:

offcourse driving a 5000cc car with lpg is fun. ok, it's slow compared to gasoline injection, but with todays prices, i'm doing 1.5 baht/km and that is a lot better than my 2500cc diesel truck which is 3.3 baht/km. And i even get a lot more comfort in the benz.

advice:

Getting people together and trying to get a lower price is asking for inferior work. Do not save money on this! Also you might want to choose the more expensive lpg injection (probably 35 - 40.000 baht) which does not lower the power of your car AND has the same mileage as running on gasoline (older constant vacuum inlet-manifold entry always uses more lpg (liters/km)) . So that will pay back to you very fast.

[tracker]

Adjusting of lpg valve:

Overheating... I'll take the risk. Why: because the watercooling system with lpg goes through the lpg vaporator. If you know that the boiling point of lpg is around -42 degrees celsius, the cooling capacity of your car is greatly enhanced. Especially if you have an evaporator which feeds an 8 cilinder... Anyway, my water-temp rarely hits over 100 degrees C and mostly sits around 80. (Sorry for your fahrenheit guys). And then know these 500se and 560se engines of the W126 series. They last over a million kilometers. They can take a beating.

Tip on safety for lpg/ngv;

As before mentioned, i have had 2 leaking "safety" valves in a row. You can check your car regularly yourself with simply using soapwater. Run the car on lpg and slowly soap the lines which run the lpg. It's the way it is done in all lpg installation stations. (be careful of moving parts if you do this!!)

question on benz:

since there are more people here with benz, anyone out there has the service cd of the w126 series? I am willing to pay for it.

hans1977:

I have no idea about the ignition, that's why i need the service cd/book. Although i know that the fuel-injection is from the first generation (electro-mechanical) from bosch, i suspect it is already an electronic injection. I need more info on this too, as i plan a lot more "hacking" on this car/engine in de future.

Edited May 19, 2008 by tracker

[tigerbeer]

i guess the only reason you would go for NGV is over the concern of LPG prices going up. Am happy with the NGV but could have actually opt for the LPG cause of less pumping stations and heavy tank.

my mileage costs 60 satang per km. LPG would be more expensive.

[tigerbeer]

BTW, just did a rough calculation. I installed my NGV in January this year and have done 10,000km exactly on it. my calculation shows me that i have saved 24,000THB since i use NGV. actually should be more since petrol prices are hovering around 38 plus baht per litre of 91 up here in chiang mai. if i was living in bangkok, i would be saving a lot more since NGV is 10.35 here and 8 baht plus in bangkok.

so an installation of 53k of which i paid for NGV should be paid off easily in the next few months.

[Guest #1man]

If you are thinking of converting to NGV then I would advise you to wait a bit.

Discussions are going on at the moment to promote NGV by reducing the conversion cost of a 4 cylinder car to 30k baht.

[hans1977]

About the overheating. I think the concern was that the valves might get overheated if you tune the car to save too much. The gas/petrol/diesel helps to cool the valves, but of course the cylinder head (cooled by your water cooling system) very significant to cool the valves.

To find out about the ignition you just look at the distributor. If it has got a capacitor attached to it, you can be quite sure that an EID Electronic Ignition Driver could be fitted. To make even more sure, you could remove the distributor cover to see if you have got the old style mechanical points fitted in there.

/Hans

Adjusting of lpg valve:

Overheating... I'll take the risk. Why: because the watercooling system with lpg goes through the lpg vaporator. If you know that the boiling point of lpg is around -42 degrees celsius, the cooling capacity of your car is greatly enhanced. Especially if you have an evaporator which feeds an 8 cilinder... Anyway, my water-temp rarely hits over 100 degrees C and mostly sits around 80. (Sorry for your fahrenheit guys). And then know these 500se and 560se engines of the W126 series. They last over a million kilometers. They can take a beating.

Tip on safety for lpg/ngv;

As before mentioned, i have had 2 leaking "safety" valves in a row. You can check your car regularly yourself with simply using soapwater. Run the car on lpg and slowly soap the lines which run the lpg. It's the way it is done in all lpg installation stations. (be careful of moving parts if you do this!!)

question on benz:

since there are more people here with benz, anyone out there has the service cd of the w126 series? I am willing to pay for it.

hans1977:

I have no idea about the ignition, that's why i need the service cd/book. Although i know that the fuel-injection is from the first generation (electro-mechanical) from bosch, i suspect it is already an electronic injection. I need more info on this too, as i plan a lot more "hacking" on this car/engine in de future.

[tracker]

hans1977:

No capacitor attached. I did not open the cap, but, according to your info, it should be an old fashioned breaker-point ignition. I haven't any problems with that. On a sidenote i have to say that my car runs terrible on gasoline. It starts perfectly, and keeping the rpm under 1200 is ok, so the car can move forward, but if i press the pedal a bit, the engine stalls. Maybe the ignition is cause !? (although i replace the fuelpump sometime ago and the car run (very fast) good on gasoline for a day, the problem is still there.)

So it might be that my ignition is optimized for the lpg, i dunno...

Another interesting part for lpg:

Since lpg has a boiling point of -42 degree C, it is very close to aircon gas which has around -38 degree. When lpg is changed from liquid into gas in the evaporator, there is a lot of heat absorbed from the cooling water. Just a bit from this, through an exchanger, would make the whole aircon system of the car obsolete (including the very high consuming compressor!), if that could cool down the interior of the car.

I know.... safety, but heck, I drive already in a lpg vehicle, which is a dangerous fact by itself, so why not... and it would definitely affect mileage (10%)...

[hans1977]

You say you have not checked inside the distributor and that you have not got any capacitor on your distributor, so what part of my information indicates that you have actually got the old style ignition system?

Anyway, i think that you have not got a problem with your ignition. but rather with your carburetor/injection. Possibly just tuning would do... I know a guy in Chonburi that seams to be very good i tuning cars, and he has got reasonable pricing as well. But maybe you live far from Chonburi?

About the AC system you suggest. I think it might be a bit of a thing to engineer, but i don't think additional security risks would necessary occur. Don't forget to make sure about the calculations, to see if it would be worth it, before you start!

/Hans

hans1977:

No capacitor attached. I did not open the cap, but, according to your info, it should be an old fashioned breaker-point ignition. I haven't any problems with that. On a sidenote i have to say that my car runs terrible on gasoline. It starts perfectly, and keeping the rpm under 1200 is ok, so the car can move forward, but if i press the pedal a bit, the engine stalls. Maybe the ignition is cause !? (although i replace the fuelpump sometime ago and the car run (very fast) good on gasoline for a day, the problem is still there.)

So it might be that my ignition is optimized for the lpg, i dunno...

Another interesting part for lpg:

Since lpg has a boiling point of -42 degree C, it is very close to aircon gas which has around -38 degree. When lpg is changed from liquid into gas in the evaporator, there is a lot of heat absorbed from the cooling water. Just a bit from this, through an exchanger, would make the whole aircon system of the car obsolete (including the very high consuming compressor!), if that could cool down the interior of the car.

I know.... safety, but heck, I drive already in a lpg vehicle, which is a dangerous fact by itself, so why not... and it would definitely affect mileage (10%)...

[tracker]

mmm, maybe i read you wrong, as i thought to read that a capacitor attached to the distributor would indicate old system. But i see now that is related to the possibility to install an electronic drive. Sorry.

I live in Nakhon Pathom province, which is about 40km west of bkk. I guess there are tuners around here too, but i rather learn and do it myself, that's my I looking for a service book/cd... I'm an electronic engineer through education, but have experience in most technical fields through experience (including safety :-)

that electronic ignition you installed: can it be adjusted to advance ignition, and if yes, how much? (any website reference to it?)

[Gary A]

As far as cooling the interior of the car with the LPG evaporator, it's a great idea. Unfortunately the volume of LPG going through the evaporator is not nearly enough to do the job.