Gas Vs Petrol

[VocalNeal]

The only drawback I can see is the room the gas tank take's up. Other than that it's a win win situation. All the taxi's use it so cant be that bad.

Is there any reason why gas conversions in Thailand, even including the factory fitted Chevy ones, do not use a "polo" shape tank in the spare wheel well, as I believe is far more common in the UK and Europe?

I can see that they may be a bit smaller, but fitting a big tank in something like a Chevy Captiva or Optra Estate surely means that you lose virtually all the practicality and point of that sort of car? Its the main thing that puts me off, certainly.

John,

My salesman says they used to have toroidal tanks here but they were imports. As there is only one "licensed" manufacturer of LPG tanks they were "phased' out.

[katabeachbum]

/quote]

And the problem with this is that your data is 14 years old while technology has moved along nicely. I'm referring to the current systems which have only been developed over the last couple of years..

The systems we developed 14 years ago with stuff from Italy, Canada and CE tanks from Poland, is still state of the art in LPG, electronic controlled injection using vehicles ECU and aditional 32 bit unit. So data still up to date. From 1998 we where also able to use the original fuelgauge for both petrol and LPG depending on which fuel was currently used. Not yet very common in LOS due to price, LPG vacuum in airintake is most common here, running very rich thus using 30% more LPG over petrol

[VocalNeal]

Funny you answered again as the more I thought about it the more I realized that the burned valves you speak of in a dual-fuel system have virtually nothing to do with the LP temps generated but rather the leaned out fuel mixture when in regular fuel mode due to the air flow restriction of the LP injector.....Again why a multi-injector system upstream from the throttle valve is required...LP gets the blame though because it seems to be the commonality but the latter is never considered as being the real problem..

Horse pucks...etc. (your words not mine)

No mass produced production engines for cars have the injectors upstream of the throttle valves (plural) otherwise they would need four throttle valves , 4 airflow sensors etc. MotoGP bikes do as do F1 but not mass produced road cars. I warrant even your VW only has one throttle body. I'll also warrant that the Prins system also doesn't retro fit the engines with 4 throttle valves. I'm sure you'll discover some Ferrari , V10 Audi or some obscure engine to disprove my statement but they don't count as they are not likely to be candidates for LPG conversion.

Where is this restriction in the air system you talk of? The LPG injector? If the system does not have individual injectors most have a simple rubber tube connected to the air inlet upstream of the one throttle body.

My Thai source of what's here and what's not has a Camry with Italian multi-point LPG injection. Started automatically on petrol etc. He says there are lots of 40,000+ baht injector LPG systems here on high end cars. He chided me for thinking only taxis run on LPG.

Kata,

Why is it important for the engine to be at 65C? Other than the vaporizer has to get up to temperature before the LPG is properly vapourized. Here with ambient at around 30C engines are up to 65C is a very short time. Is it something else? because if so I'll get the guys to start mine on petrol everyday, instead of current practice of starting on LPG and letting it warm up. Actually most times they drive slowly, because they have to, down the soi. Before they get to the main road the temp guage is already at "normal"

Edited May 20, 2010 by VocalNeal

[katabeachbum]

Kata,

Why is it important for the engine to be at 65C? Other than the vaporizer has to get up to temperature before the LPG is properly vapourized. Here with ambient at around 30C engines are up to 65C is a very short time. Is it something else? because if so I'll get the guys to start mine on petrol everyday, instead of current practice of starting on LPG and letting it warm up. Actually most times they drive slowly, because they have to, down the soi. Before they get to the main road the temp guage is already at "normal"

Vaporizer starts work properly at 65C, before this engine is more vounerable to damage from not properly vapourized LPG and risk of backfires increase. Most electronic systems ALWAYS start on petrol (to lubricate petrolsystem, smoth idle when colder than 80C and avoid backfires), and then switch to LPG when 65C is checked or later depending on setting.

I agree 30C to 65C is a very short time, but those 2-4 minutes are cruisal to avoid LPG problems/extensive wear on engine.

Engines dont like warm up/idle at all, combustion is far from ideal when cold engine idles. For a manual switch system I would start on petrol, fasten seatbelt and move. Temp gauge normal, or lets say 4 minutes of driving (not idling) switch to LPG.

[WarpSpeed]

/quote]

And the problem with this is that your data is 14 years old while technology has moved along nicely. I'm referring to the current systems which have only been developed over the last couple of years..

The systems we developed 14 years ago with stuff from Italy, Canada and CE tanks from Poland, is still state of the art in LPG, electronic controlled injection using vehicles ECU and aditional 32 bit unit. So data still up to date. From 1998 we where also able to use the original fuelgauge for both petrol and LPG depending on which fuel was currently used. Not yet very common in LOS due to price, LPG vacuum in airintake is most common here, running very rich thus using 30% more LPG over petrol

Yes as I said the LP side runs very rich and the fuel side runs very lean fuel wise due to low air intake pressures especially at higher RPMS now you've finally come around to my original premise.....Congratulations..... Now for part 2, which of these 2 conditions causes burned valves and seats?? Too rich or too lean? So LP being too rich is not the entire problem and regular fuel being too lean is just as much a problem, it's a combined issue not exclusive to LP... Now on the matter of pistons, it's the lean condition and improper timing that causes detonation in fuel mode and creates holes in pistons.... Now we've come full circle..

Not good on either side, complete opposites stoichiometric wise and too wide a swing to be adjusted properly or for the average ECU to compensate for.. And to make matters worse the electronics installed with these units are not sophisticated and also do not utilize the cars gauge for both fuels nor allow any range of adjustments...

The units you are referring to require a diagnostic tuning program and technician, just how many installers here do you think actually check anything related to proper mixing and ECU adjustments??

[WarpSpeed]

Funny you answered again as the more I thought about it the more I realized that the burned valves you speak of in a dual-fuel system have virtually nothing to do with the LP temps generated but rather the leaned out fuel mixture when in regular fuel mode due to the air flow restriction of the LP injector.....Again why a multi-injector system upstream from the throttle valve is required...LP gets the blame though because it seems to be the commonality but the latter is never considered as being the real problem..

Horse pucks...etc. (your words not mine)

No mass produced production engines for cars have the injectors upstream of the throttle valves (plural) otherwise they would need four throttle valves , 4 airflow sensors etc. MotoGP bikes do as do F1 but not mass produced road cars.

:D Of course they do!!! Have you never heard of direct injection?? The injector injects fuel directly into the combustion chamber and uses a single MASS air flow sensor and throttle body to measure air flow and determine how long the injector needs to stay open!!!

I warrant even your VW only has one throttle body. I'll also warrant that the Prins system also doesn't retro fit the engines with 4 throttle valves.

No one said it does I said 4 INJECTORS!! You should stay in the ice cream section this is way too advanced for you...

I'm sure you'll discover some Ferrari , V10 Audi or some obscure engine to disprove my statement but they don't count as they are not likely to be candidates for LPG conversion.

Where is this restriction in the air system you talk of? The LPG injector? If the system does not have individual injectors most have a simple rubber tube connected to the air inlet upstream of the one throttle body. :D Oh let me catch my breath a moment.........In....Out...... A simple rubber tube????? Go back to playing in your sand box you're making a right fool of yourself.. The "simple rubber tube" you're speaking of is mounted into a billet machined LP injector which is machined to create a vortex that causes a suction that pulls the LP into the intake and it is quite a bit smaller in diameter to the intake hose depending on the intake hoses size..What is this pictured below then genius??? Sorry I know it's poor form but I can't help but laugh again :D

This is looking closest to the throttle body from that direction towards the air filter but a well versed technician should already know this.. Top photo shows proper installation with the smooth side of the venturi which smooths the air flow and creates a Vortex of vaccum to inject the LP installed against air flow but number 2 below is how mine was installed with the rough side and the injector facing air flow, if a technician here can't even get something this simple installed properly how is the really technical part of these systems such as fuel mixture going to work properly?? Note the extreme size difference between the outer edge which represents the intake diameter and the reduced venturi size in the center, if anyone thinks this does not have a serious effect on regular fuel performance then I can only feel pity for that person...

These are the different sides out of the cool air intake

My Thai source of what's here and what's not has a Camry with Italian multi-point LPG injection. Started automatically on petrol etc. He says there are lots of 40,000+ baht injector LPG systems here on high end cars. He chided me for thinking only taxis run on LPG.

That was a question I had, not an absolute, I inquired about what was available here and most commonly used but the prins system is not used in abundance I can assure you due to cost and complication and since the preponderance of conversions here are older model cars..

Kata,

*edit* Just realized that maybe you're handicapped in not understanding the term "upstream" either, in this case it means in the direction of airflow closest to the combustion chamber not the air filter..

Edited May 20, 2010 by WarpSpeed

[katabeachbum]

attachment=114140:LP_injector.JPG]

These are the different sides out of the cool air intake

Worst designed LPG feeder I have ever seen, and no wonder engines brake down either running LPG or petrol, since the air intake is almost blocked. Shocked.

[WarpSpeed]

I guess now your beginning to understand...

[MoonRiverOasis]

I have it and in terms of savings I believe it's worth it but in terms of vehicle wear and tear the jury is still out from my point of view, admittedly I'm not fully up to specs on it yet though it's a new adventure.

Your information about the start up is new to me, so intended only as a learning process I'm curious to know how exactly would it be detrimental to get a hotter fire upon cold start? Can you tell me what damage that is supposed to create?

Conclusion.......I have plenty of my own questions to answer on this one before I can answer conclusively..

You appear to have gone from a relative LPG novice, to the LPG master awfully quickly there warp

OK, benefit of the doubt - you probably have a several decades of technical expertise in other areas which have allowed to you come up to speed quickly on LPG (the same goes for me with commonrail engines I guess), but another reality is that although Katabeachbum is not a native English speaker, the guy does know a thing or two about pretty much most of the topics discussed here too..

If we all consider ourselves professionals, should we not present ourselves that way? Just some food for thought..

Peace

[katabeachbum]

I guess now your beginning to understand...

yepp, no LPG/CNG conversion is better than the parts, installation and knowledge invested

BTW, does anyone know if the LPG in LOS for vehicles is Butane or Propane? Different ECU settings for these to LPGs to run perfect

Edited May 20, 2010 by katabeachbum

[WarpSpeed]

I guess now your beginning to understand...

yepp, no LPG/CNG conversion is better than the parts, installation and knowledge invested

BTW, does anyone know if the LPG in LOS for vehicles is Butane or Propane? Different ECU settings for these to LPGs to run perfect

Good question, I've been wondering the same thing, butane is just a bit more volatile and efficient then is propane and though not much difference any such difference would still need to be accounted for..

Don't agree on the "no conversion" aspect though as I think it has uses in a given application taken on a case by case basis with the current price of gasoline...

[WarpSpeed]

I have it and in terms of savings I believe it's worth it but in terms of vehicle wear and tear the jury is still out from my point of view, admittedly I'm not fully up to specs on it yet though it's a new adventure.

Your information about the start up is new to me, so intended only as a learning process I'm curious to know how exactly would it be detrimental to get a hotter fire upon cold start? Can you tell me what damage that is supposed to create?

Conclusion.......I have plenty of my own questions to answer on this one before I can answer conclusively..

You appear to have gone from a relative LPG novice, to the LPG master awfully quickly there warp

OK, benefit of the doubt - you probably have a several decades of technical expertise in other areas which have allowed to you come up to speed quickly on LPG (the same goes for me with commonrail engines I guess), but another reality is that although Katabeachbum is not a native English speaker, the guy does know a thing or two about pretty much most of the topics discussed here too..

If we all consider ourselves professionals, should we not present ourselves that way? Just some food for thought..

Peace

Yep, quick study and all that coupled with extensive engineering and empirical experience is what moves me towards the front of the pack in everything I do in short order..

Not sure what your last sentence says though as I've merely had a professional and in depth discussion about the pros and cons of LP with the exception of a few posters who have had the brass to attempt to contradict and twist my posts out of context and got called hard on it.. Don't think that I've made a single demeaning comment in Kata's direction that I can recall sometimes it gets hot and heavy though..

[WarpSpeed]

CNG is not intended as a conversion application nor is it dual fuel..

CNG is presently the most common conversion, and except for Tatas pickup they are all dual fuel

I'll give you that, I stand corrected misinformed... Though when I say "conversion" my meaning is on existing vehicles where I believe LP is more common, not factory or dealer offered conversions...

Edited May 20, 2010 by WarpSpeed

[WarpSpeed]

Weeeeellllll.........Now that you mention it, I didn't want to say anything..........

[WarpSpeed]

Geezzzz....You're just not happy without a confrontation are you T/A??? Must be a bitch to be so insecure.....

[mdechgan]

I have to agree in that LPG or CNG conversions on a car designed for petrol does not work or is cost effective.

The savings one gets at the gas pump isn't worth the cost of engine rebuilds or head work.

I have seen many Toyota engines destroyed by LPG and CNG conversions at my local machine shop.

I even have honda engine in my factory that isn't even worth rebuilding after LPG use.

The problem is petrol has a combustion temperature of about 280 degrees C. LPG has about a 425 degrees while NGV is about 475 degrees.

Unless your car is diesel or has steel cylinder linings and high performance stainless steel or titanium valves, GAS spark plugs, stainless steel intake and exhaust and a heavy duty cooling system your car will just get wasted. Most taxi conversions last only about 1 - 1.5 years or 6 months if its a dual shift car (2 drivers per day) Most taxi drivers don't care because they need every baht they can get per shift while the taxi owners have a shift of mechanics that work on cars all day.

The temperatures are so high and gases so corrosive the light aluminum alloy engines of those civis or altis will be destroyed in no time. Most people won't notice the damage done until the engine is taken apart. The engines were never designed to remove so much heat. Heat from the valves are removed by the valve seats through the cylinder head. Heavier oil does not help. Its like an overheating engine but the water temperature gauge doesn't show it.

The only time I would suggest a LPG or CNG conversion is if it comes with it from the factory and the engine and car is designed for it like the newer NGT Benz or CNG chevrolet, multi fuel volvos or Tata.

What interests me are the diesel conversions because diesel engines are strong as an ox (steel linings) and they do get better mileage.

I think the best conversions are the duel/ancillary fuel conversions where the gas is injected and mixed pre throttle body while keeping the original system intact. So its like tricking the ecu with a fuel/air mixture already inside the intake manifold so the ecu adjusts and leans the fuel injectors. But then one is only substituting one fuel for another.

[WarpSpeed]

I have to agree in that LPG or CNG conversions on a car designed for petrol does not work or is cost effective.

The savings one gets at the gas pump isn't worth the cost of engine rebuilds or head work.

I have seen many Toyota engines destroyed by LPG and CNG conversions at my local machine shop.

I even have honda engine in my factory that isn't even worth rebuilding after LPG use.

The problem is petrol has a combustion temperature of about 280 degrees C. LPG has about a 425 degrees while NGV is about 475 degrees.

Unless your car is diesel or has steel cylinder linings and high performance stainless steel or titanium valves, GAS spark plugs, stainless steel intake and exhaust and a heavy duty cooling system your car will just get wasted. Most taxi conversions last only about 1 - 1.5 years or 6 months if its a dual shift car (2 drivers per day) Most taxi drivers don't care because they need every baht they can get per shift while the taxi owners have a shift of mechanics that work on cars all day.

The temperatures are so high and gases so corrosive the light aluminum alloy engines of those civis or altis will be destroyed in no time. Most people won't notice the damage done until the engine is taken apart. The engines were never designed to remove so much heat. Heat from the valves are removed by the valve seats through the cylinder head. Heavier oil does not help. Its like an overheating engine but the water temperature gauge doesn't show it.

Agreed, no one suggested heavier oil, as it does not dissipate heat quick enough nor leave enough residual lubricant, the correct suggestion was synthetic or equivalent additive such as Prolong, Duralube, Energy Release, etc...

The only time I would suggest a LPG or CNG conversion is if it comes with it from the factory and the engine and car is designed for it like the newer NGT Benz or CNG chevrolet, multi fuel volvos or Tata.

What interests me are the diesel conversions because diesel engines are strong as an ox (steel linings) and they do get better mileage.

I think the best conversions are the duel/ancillary fuel conversions where the gas is injected and mixed pre throttle body while keeping the original system intact. So its like tricking the ecu with a fuel/air mixture already inside the intake manifold so the ecu adjusts and leans the fuel injectors. But then one is only substituting one fuel for another.

There has been a rather comprehensive discussion on this here on the previous pages with numerous facts presented dispelling this line of thinking... Just because the system is installed after the throttle body does not make it necessary in any way to effect the OEM throttle body or fuel injection system, quite the opposite, it provides a much wider range of adjustability, performance and efficiency for both systems when in operation..

[katabeachbum]

I have it and in terms of savings I believe it's worth it but in terms of vehicle wear and tear the jury is still out from my point of view, admittedly I'm not fully up to specs on it yet though it's a new adventure.

Your information about the start up is new to me, so intended only as a learning process I'm curious to know how exactly would it be detrimental to get a hotter fire upon cold start? Can you tell me what damage that is supposed to create?

Conclusion.......I have plenty of my own questions to answer on this one before I can answer conclusively..

You appear to have gone from a relative LPG novice, to the LPG master awfully quickly there warp

OK, benefit of the doubt - you probably have a several decades of technical expertise in other areas which have allowed to you come up to speed quickly on LPG (the same goes for me with commonrail engines I guess), but another reality is that although Katabeachbum is not a native English speaker, the guy does know a thing or two about pretty much most of the topics discussed here too..

If we all consider ourselves professionals, should we not present ourselves that way? Just some food for thought..

Peace

Yep, quick study and all that coupled with extensive engineering and empirical experience is what moves me towards the front of the pack in everything I do in short order..

Not sure what your last sentence says though as I've merely had a professional and in depth discussion about the pros and cons of LP with the exception of a few posters who have had the brass to attempt to contradict and twist my posts out of context and got called hard on it.. Don't think that I've made a single demeaning comment in Kata's direction that I can recall sometimes it gets hot and heavy though..

Hmmmmmmm, none of us have a chance then, eh Warpy. Perhaps the rest of us must retire to the knitting forum.

hehehehe, brilliant transam

[katabeachbum]

CNG is not intended as a conversion application nor is it dual fuel..

CNG is presently the most common conversion, and except for Tatas pickup they are all dual fuel

I'll give you that, I stand corrected misinformed... Though when I say "conversion" my meaning is on existing vehicles where I believe LP is more common, not factory or dealer offered conversions...

There are no vehicles in LOS leaving factory LPG equipped, while there are several CNG equipped.

More existing vehicles presently converse to CNG than LPG. LPG is being phased out by removing subsidises, while CNG is being promoted by government in LOS

[katabeachbum]

I have to agree in that LPG or CNG conversions on a car designed for petrol does not work or is cost effective.

The savings one gets at the gas pump isn't worth the cost of engine rebuilds or head work.

I have seen many Toyota engines destroyed by LPG and CNG conversions at my local machine shop.

I even have honda engine in my factory that isn't even worth rebuilding after LPG use.

The problem is petrol has a combustion temperature of about 280 degrees C. LPG has about a 425 degrees while NGV is about 475 degrees.

Unless your car is diesel or has steel cylinder linings and high performance stainless steel or titanium valves, GAS spark plugs, stainless steel intake and exhaust and a heavy duty cooling system your car will just get wasted. Most taxi conversions last only about 1 - 1.5 years or 6 months if its a dual shift car (2 drivers per day) Most taxi drivers don't care because they need every baht they can get per shift while the taxi owners have a shift of mechanics that work on cars all day.

The temperatures are so high and gases so corrosive the light aluminum alloy engines of those civis or altis will be destroyed in no time. Most people won't notice the damage done until the engine is taken apart. The engines were never designed to remove so much heat. Heat from the valves are removed by the valve seats through the cylinder head. Heavier oil does not help. Its like an overheating engine but the water temperature gauge doesn't show it.

The only time I would suggest a LPG or CNG conversion is if it comes with it from the factory and the engine and car is designed for it like the newer NGT Benz or CNG chevrolet, multi fuel volvos or Tata.

What interests me are the diesel conversions because diesel engines are strong as an ox (steel linings) and they do get better mileage.

I think the best conversions are the duel/ancillary fuel conversions where the gas is injected and mixed pre throttle body while keeping the original system intact. So its like tricking the ecu with a fuel/air mixture already inside the intake manifold so the ecu adjusts and leans the fuel injectors. But then one is only substituting one fuel for another.

Thanks for that, very informative and l agree.

less than 3000cc and one cylinderhead I partly agree for a vacumsystem. Electronic injection with more auto petrol running time and replaced valves can run +200k km.

V8 and V10 more than 5000cc has run without problems for 300-400k km. Ford Coke Trucks (more than 100 trucks in 1998 only) on LPG, electronic controlled vacumsystems, and several other V8 and V10s.

[WarpSpeed]

CNG is not intended as a conversion application nor is it dual fuel..

CNG is presently the most common conversion, and except for Tatas pickup they are all dual fuel

I'll give you that, I stand corrected misinformed... Though when I say "conversion" my meaning is on existing vehicles where I believe LP is more common, not factory or dealer offered conversions...

There are no vehicles in LOS leaving factory LPG equipped, while there are several CNG equipped.

More existing vehicles presently converse to CNG than LPG. LPG is being phased out by removing subsidises, while CNG is being promoted by government in LOS

Yeah and where did I say otherwise??

[WarpSpeed]

You appear to have gone from a relative LPG novice, to the LPG master awfully quickly there warp

OK, benefit of the doubt - you probably have a several decades of technical expertise in other areas which have allowed to you come up to speed quickly on LPG (the same goes for me with commonrail engines I guess), but another reality is that although Katabeachbum is not a native English speaker, the guy does know a thing or two about pretty much most of the topics discussed here too..

If we all consider ourselves professionals, should we not present ourselves that way? Just some food for thought..

Peace

Yep, quick study and all that coupled with extensive engineering and empirical experience is what moves me towards the front of the pack in everything I do in short order..

Not sure what your last sentence says though as I've merely had a professional and in depth discussion about the pros and cons of LP with the exception of a few posters who have had the brass to attempt to contradict and twist my posts out of context and got called hard on it.. Don't think that I've made a single demeaning comment in Kata's direction that I can recall sometimes it gets hot and heavy though..

Hmmmmmmm, none of us have a chance then, eh Warpy. Perhaps the rest of us must retire to the knitting forum.

hehehehe, brilliant transam

Yeah it was stoke of brilliance befitting of our cheeky British isle cousins...

[WarpSpeed]

Geezzzz....You're just not happy without a confrontation are you T/A??? Must be a bitch to be so insecure.....

( confrontation ) Pot calling the kettle black, eh.

( insecure ) You have revealed to all many times here all about insecurity.

Now back to topic, of which l haven't said a word yet, but if l do l will be wrong, eh Warpy

Yeah I'll call you on that wise arse, prove me wrong, prove the FACTS I've posted are wrong....Instead of just posting derogatory wise arse remarks this is a technical discussion after all and like you said you've posted nothing informative only inflammatory trolling posts so if you've nothing of value to contribute, take off...Never fails when one of you or your opinion is validly shot down with real facts and empirical experience your ego just can't handle it and then the discussion goes all tits up to deflect from the real topic at hand and your shortcomings in the debate..

Got anything of value to add or just more mindless antagonism??

Edited May 21, 2010 by WarpSpeed

[alexbrouwer1]

Never an LPG car for me anymore. More maintenance costs with LPG, engines is running hotter, problems with cylinder heads, problems with adjusting the LPG injection system. Maybe i was just unlucky, but not an LPG car for me again.

Diesel car is my first choice, diesel engines have low maintenance costs, had several diesel cars when i was living in Europe, easily running up to 300.000-400.000 km without problems, still going strong.

If Honda would bring their 2.2 diesel CRV or Accord here on the market or Toyota their 2.0 D4D engine in the Camry, i would be in for one.

Have currently petrol cars here in LOS, never had a problem with them so far.

I have no experiences with NGV.

[jayinoz]

The poll has been pretty much even between NO WILL NOT CHANGE due to extra wear and tear on engine and YES WILL DO FOR THE $$$ SAVINGS...

Half that state money savings not worth it and a be FAT WHO CARES about the enviroment gets a big ZERO.

I knew the Enviro factor would get next to nothing, all this horse ballocks about the politicians giving a cr&^... When you come down to it- it is all about whether you want to save the dollars at the risk of your engines longevitity.

As a novice I have heard far too many times that the longevitiy of the motor will be affected- so I believe it is true... Yet I will save 40% odd savings every week on Gas. That will save me near 1000bt every week, as I drive a lot around Thailand.

Do the Gas fitters actually cover the engine in their typical 2 year warranty- I would suggest NO???

Is the ROI good enough- YES, if the engine lasts nearly as long as it would on petrol.

I am sure many experienced engineers do believe that more hassles come from gas... yet the cost savings may justify the hassles in the long run- if you lucky.

So I will convert my 10 year ols car to gas- but i would be reluctant to do so on a much newer car than runs efficiently already.

Lot of debating on this topic- good. Good value thread to read if thinking of converting to gas...

[katabeachbum]

The poll has been pretty much even between NO WILL NOT CHANGE due to extra wear and tear on engine and YES WILL DO FOR THE $$$ SAVINGS...

Half that state money savings not worth it and a be FAT WHO CARES about the enviroment gets a big ZERO.

I knew the Enviro factor would get next to nothing, all this horse ballocks about the politicians giving a cr&^... When you come down to it- it is all about whether you want to save the dollars at the risk of your engines longevitity.

As a novice I have heard far too many times that the longevitiy of the motor will be affected- so I believe it is true... Yet I will save 40% odd savings every week on Gas. That will save me near 1000bt every week, as I drive a lot around Thailand.

Do the Gas fitters actually cover the engine in their typical 2 year warranty- I would suggest NO???

Is the ROI good enough- YES, if the engine lasts nearly as long as it would on petrol.

I am sure many experienced engineers do believe that more hassles come from gas... yet the cost savings may justify the hassles in the long run- if you lucky.

So I will convert my 10 year ols car to gas- but i would be reluctant to do so on a much newer car than runs efficiently already.

Lot of debating on this topic- good. Good value thread to read if thinking of converting to gas...

That's cool. In your case perhaps financially it will work, worth the risk etc and the cost verses probs worth the risk.

depends on what 10 year old engine it is, some do ok, some dont, but 50k baht saving in a yearon fuel could cover a "new" 10 year old engine

[WarpSpeed]

Still waiting for something of value from you T/A, I guess that's too much to ask??

[monty]

Gentlemen, too much silly bickering in this thread!

Threads like this should be a valuable source of information and experience, and should not be a place for childish behavior!

Ok, this said, I'll throw in my experience with LPG, not as an installer but as a user.

I currently use LPG on 3 vehicles:

27 year old Volvo 245, almost 300,000 km mileage (last 100,000 on LPG), vacuum controlled.

5 year old Nissan Cefiro, 100,000 km, Italian multipoint LPG injection (last 40,000 on LPG).

10 year old VW Caravelle, 210,000 km, all of them on LPG (vacuum controlled).

Now I'll copy and paste parts of posts on which I can give some more experience:

Petrol engines do not run LPG properly until cooling water has reached 65 Centigrades, cause this is the needed temp in evaporator to work. Most electronic(usually Italian or Canadian) LPG systems starts engine automaticly on petrol, and switches to LPG when 65Centigrades is reached in coolingwater. A good electronic system uses the same fuel gauge for petrol and LPG, depending on whats being run. Engine also backfires easily on LPG before vacuum in airflow is reached.

Can't really say I have the same experience. Apart from the Nissan which starts on petrol, and then switches to LPG when cooling system reaches 60 degrees, both other vehicles start perfectly on LPG from cold, and never backfire. I do start them on petrol, but with only reason to keep the petrol injection system in good shape. Let it dry out and you'll be in for a disappointment when you do need to run on petrol!

Most engines are not designed for the higher combustion temperature with LPG, so premature damage to valves is common for highreving (over 5000rpm) engines with 4 valves. Most BKK taxis running LPG or CNG has a modified 1600cc engine, similar to the engine provided by Toyota Altis CNG.

Partly true. LPG indeed burns hotter, but the most damaging issue for the valves is the lack of cooling effect of LPG. Petrol has a pretty good cooling effect when it comes into contact with the valves/seats, LPG does not.

I doubt all those LPG running toyota's in Bkk are much modified. Installing a 2 stroke "valve saver" injection system AND keeping it filled up, almost negates any problems of the LPG on the valves. The oil has a much greater cooling effect then petrol, so it can partly offset the hotter combustion temperature of LPG.

for petrol engines less than 3000cc using old fashioned vacuum system expect 30% more fuel/km. electronic controlled injection system, expect 10% more fuel/km. 10-30% drop in power for non turbo engines. f

Roughly correct, although in my experience on a good quality, properly tuned vacuum controller increase in consumption should not be much over 20%. You do have to re-tune often though, I advise at least every 2 or 3 months. Only takes a minute!

for turbo intercooled petrolengines power can increase due to the cool LPG entering combustion chamber allowing more O2 in air.

I was of the impression that the biggest factor in getting more power out of a turbo charged engine came from the high octane number of LPG. I doubt that the injection of cool LPG makes a difference with the injection of cool petrol! In the end it's the temperature of the compressed air which dictates oxygen content/density.

One added advantage of turbo charged engines, is that the valves are very likely to withstand the higher temperatures when running on LPG!

[monty]

It seems that a good synthetic and or oil additive should guard against that, they stand up better to higher temps and provide better residual lubrication then conventional oil... Agreed cheap oil and improper maintenance will otherwise cause problems....

Engine oil does not lubricate the actual valve/seat. It does lubricate the valve stem though...Doubt it would make any difference on the valve issue.

As for performance this is another reason a level comparison is not possible as with the LP injector installed, the car is undoubtedly not getting a full breath with every stroke as the injector being up stream causes a severe restriction, preventing an equal comparison to be had on either performance or mileage as all things are not equal..

Had me scratching my head a bit Ok, I think you mean the venturi ring where the LPG gets introduced in the intake air! Is indeed one of the reasons why performance on petrol will go down after you install the vacuum controlled LPG system.

Funny you answered again as the more I thought about it the more I realized that the burned valves you speak of in a dual-fuel system have virtually nothing to do with the LP temps generated but rather the leaned out fuel mixture when in regular fuel mode due to the air flow restriction of the LP injector

Other way around! You reduce the air intake, then you increase mixture (if you inject the same amount of petrol). Which is the opposite of running lean. And most fuel injected engines have an oxygen sensor in the exhaust, so whatever you do on the inlet side, the proper amount of petrol will always be injected for a proper mixture...

[monty]

most LPG engines run very rich LPG mix as a vacuum system adding LPG in engines airintake. thus the decreased milage running LPG. most Dual fuel run less than 1% on petrol, and airflow is not restricted with a good designed aluminum LPG distributor/LPG feeder

Haven't seen an LPG feeder yet which does not restrict airflow to a certain extent. It's based on the venturi effect, which needs a small funnel like reduction in diameter.

This is actually one of the bigger advantages of the multipoint LPG injection systems, having no effect whatsoever on petrol operation!

No mass produced production engines for cars have the injectors upstream of the throttle valves (plural) otherwise they would need four throttle valves , 4 airflow sensors etc. MotoGP bikes do as do F1 but not mass produced road cars. I warrant even your VW only has one throttle body

Huh? All my fuel injected cars have one throttle body and 4 injectors! The injectors sit right in front where the inlet manifold (after splitting 4-ways after the throttle body) is mounted to the engine...The Nissan has 6 injectors! (ha actually 12, 6 petrol, and 6 LPG )

I have to agree in that LPG or CNG conversions on a car designed for petrol does not work or is cost effective.

The savings one gets at the gas pump isn't worth the cost of engine rebuilds or head work.

Not in my case! In the combined 350,000 km ran on LPG I have saved close to 600,000 Baht on fuel costs, and as of now haven't had one engine needing an overhaul or rebuild. Admittedly 2 out of 3 cars are used commercially and run more km's per year then the average consumer car would do...