Gas Injection?

[Mr_Slim]

I will be doing an LPG conversion very soon (maybe next week) and am just checking with people who have done it before, the costs i am looking at.

Keeping in mind the guaranteed $2K back from the government, i'm anticipating the system to cost about $1000 ($3000 - $2000), however that is for standard run-of-the-mill LPG.

I've done some searching and found a thread a few months back re: gas injection, and it sounds pretty grouse. What i read from it was that basically liquid gas injection = better than petrol fuel injection, and cheaper too.

Does anyone have any experience in actually using Gas Injection, and do they know how much it costs?

When i go ahead with the gas system, is it recommended that i keep my petrol tank, or can i make it dedicated gas? I know it is nice to have 63L of petrol spare if i need it, but it would make the car heavy and slow which is no good. (if i make it dedicated gas, how much to do this vs. normal conversion?)

I know i can find the answers to all these by ringing some LPG conversion joints, but i'd rather hear it from some impartial people before i hear it from sales people, if you know what i mean.

Thanks guys, i appreciate it

[Mr_Slim]

nobody knows?

basically my options appear to be:

Dual Fuel
Gas Injection
Sequential Gas Injection

Maybe i only think there is a difference between the 2nd and 3rd. But i read somewhere else that there are both Gas and Sequential Gas. In that case, i imagine Sequential Gas is more powerful than std, just as the Ecotec with sequential f/inj is better than the Buick with std f/inj.

Can anyone help me out here? I just wanna get all my facts right, so i know exactly what to buy.

Thanks guys

[Cheap6]

The replies may be slow in coming because in some ways the questions you have asked are like "How long is a piece of string?".

There are various types of conventional, non-EFI, gas systems and two basic types of EFI gas: vapour phase and liquid phase. Which is better depends on what your priorities are and what each will cost.

If the aim is to save money, one of the conventional systems will be better as the extra initial outlay takes too long to recover; the difference in cost is amortised over he [U]incremental[U] improvement in economy. 50% higher cost for 10% increase in fuel economy at 50cpl ? Not too clever. For optimum performance and fuel economy (not cost), the injected types are better.

As far as I am aware the liquid phase injection types are still not widely available and almost certainly not for a VP.

My opinion is that it is safest to use what GMH did for the systems it approved when VP's were new (a similar system was carried over into VS and early VT) ie. Impco. Be aware that each installer has there own way of doing things, even using the same basic components, which can affect the success of a conversion. Select your installer carefuly, asking to see similar conversions etc. The LPG supplement for VP (and VS) is still available (~$60) if you are keen enough to find it.

I am not a big fan of he 'gas ring' type set ups.

(Yes, I have an Impco based system which I fitted myself except for the gas lines. It is very similar to the GMH approved systems with a few changes because of component availability, my own thoughts on how it should be done and what I am prepared to put up with. I haven't bothered with the LPG memcal, for eg. While I am sure there is some performance difference on LPG vs petrol, it is not readily apparent even when switching straight from one fuel to the other.)

It will cost extra to remove the fuel tank, injectors etc, so I figure that it is better to leave them in place, live with the extra weight and enjoy the extra range available ie. go dual fuel.

[defa]

i have seen gas injectors on ebay before. i would be very keen to hear about gas injection from anyone that has it. you can get great power out of gas if setup right.

[defa]

http://cgi.ebay.com.au/Sequential-Ga...QQcmdZViewItem

[Cheap6]

That's vapour phase (sequential or not), note the fuel pressure regulator/converter - the big thing with the water hoses and lock off solenoid valve, also the fittings for the hoses out of the injectors.

Factory approved VE is vapour injection, perhaps that would be easiest to find feedback on.

Another reason to leave the petrol system in place is that it is then easy to swap the gas into another car, say a VS.

There is more than one type of closed loop fuel computer for the Impco systems too. The learning type is better but significantly more expensive. The GMH system used the learning type.

[defa]

i did wonder why there was a convertor there. i didnt' really read it properly. maybe i should have before posting it up there.

[Mr_Slim]

the cost of the system while important isn't a massive issue for me, because firstly with $2000 rebate from the government, and doing 800km a week i would make back the coin reasonably quickly.

I'm considering doing it on 3 cars - my VP, my dad's VS, or possibly a VX, which dad is considering purchasing. I'm also considering selling my VP and buying a VS.

i think i would be ok with the extra weight of dual fuel, only if i was to get a gas injection system with a seperate computer, so i can take advantage of the higher octane fuel.

I have a feeling though if i'm going to go to the trouble of doing this, i should buy a newer car (VS probably) and hang onto it for awhile

[Mr_Slim]

just an update guys, i spoke to a few LPG guys around sydney (the Gas Man was one of them) and i got about the same price from each, but the results are different.

1st place i called: Local LPG guy
Dual Fuel Throttle Body Injection - $2600 -slight decrease in performance from petrol
Full Liquid Injection - $4500 - mainly only for late model cars (05 onwards) and won't provide better performance than above.

Quote "it is impossible to get better performance out of gas compared to petrol"

2nd place i called: The Gas Man
Dual Fuel: $2700 - slight decrease in performance, however it is possible to get an increase depending on mods and how they tune the computer
Full Liquid Injection $4500 - basically the same as the above, would provide about the same performance, but mainly for late model cars due to emission laws

3rd place i called: Brody Automotive (referred through Parnell's LPG)
Don't do duel fuel
Full Vapour Injection - $4500 - no increase in performance, but there is reduced emissions, reduced backfiring.


I think out of those 3 i would probably go with option2, however he was hesitent to say that you could potentially get more power out of gas. Option1 said although gas has a higher octane, it produces less energy than petrol, therefore less power. This was backed up by option2, but he claims you can still get more power.

I'm leaning towards the notion that more power isnt a possibility. despite a higher octane, lower energy levels means less power in my mind. i guess if i really wanna go fast ill flick over to petrol, but most of the time i sit in traffic and power isn't really a problem.

i think i have to start looking for a VS though, to make it worthwhile

[Mr_Slim]

oh and as for going straight gas - eg. no petrol at all, ever - it is possible, and does cost extra. however there is basically no benefit at all in doing so apparently.

the gas tank can't fit in the same spot at the fuel tank was, it still remains int he boot, so no saving in space. The only advantage you would get is the slight drop in weight by not having a fuel tank. however you will pay a fair amount of money for them to rip all that stuff out

[samuels]

I will be doing an LPG conversion very soon (maybe next week) and am just checking with people who have done it before, the costs i am looking at.

Keeping in mind the guaranteed $2K back from the government, i'm anticipating the system to cost about $1000 ($3000 - $2000), however that is for standard run-of-the-mill LPG.

I've done some searching and found a thread a few months back re: gas injection, and it sounds pretty grouse. What i read from it was that basically liquid gas injection = better than petrol fuel injection, and cheaper too.

Does anyone have any experience in actually using Gas Injection, and do they know how much it costs?

When i go ahead with the gas system, is it recommended that i keep my petrol tank, or can i make it dedicated gas? I know it is nice to have 63L of petrol spare if i need it, but it would make the car heavy and slow which is no good. (if i make it dedicated gas, how much to do this vs. normal conversion?)

I know i can find the answers to all these by ringing some LPG conversion joints, but i'd rather hear it from some impartial people before i hear it from sales people, if you know what i mean.

Thanks guys, i appreciate it

i'd be looking at dual fuel....personally,you only need a 1/4 of a tank,so won't make car to heavy,it's recommended that you use the petrol at least once a week for approx 1/2 hour.
you won't get much change back from $4000(i'm only approximating with this price)..i priced gas conversion 15 years ago and back then it was $2000.

[samuels]

just an update guys, i spoke to a few LPG guys around sydney (the Gas Man was one of them) and i got about the same price from each, but the results are different.

1st place i called: Local LPG guy
Dual Fuel Throttle Body Injection - $2600 -slight decrease in performance from petrol
Full Liquid Injection - $4500 - mainly only for late model cars (05 onwards) and won't provide better performance than above.

Quote "it is impossible to get better performance out of gas compared to petrol"

2nd place i called: The Gas Man
Dual Fuel: $2700 - slight decrease in performance, however it is possible to get an increase depending on mods and how they tune the computer
Full Liquid Injection $4500 - basically the same as the above, would provide about the same performance, but mainly for late model cars due to emission laws

3rd place i called: Brody Automotive (referred through Parnell's LPG)
Don't do duel fuel
Full Vapour Injection - $4500 - no increase in performance, but there is reduced emissions, reduced backfiring.


I think out of those 3 i would probably go with option2, however he was hesitent to say that you could potentially get more power out of gas. Option1 said although gas has a higher octane, it produces less energy than petrol, therefore less power. This was backed up by option2, but he claims you can still get more power.

I'm leaning towards the notion that more power isnt a possibility. despite a higher octane, lower energy levels means less power in my mind. i guess if i really wanna go fast ill flick over to petrol, but most of the time i sit in traffic and power isn't really a problem.

i think i have to start looking for a VS though, to make it worthwhile

if your looking for increased power from gas ,you won't get it.(as well as fuel economy)you will get the economy,you may gain 0.5 % power even with fine tuning.
the government are offering this rebate in the hope everyone will take advantage of it,as soon as the numbers suit the government you watch,the price of petrol will fall remarkably..also there is a scheme going on out there... if someone offers you more than market value for your car,they say you can take anything you want off it,but you must leave the motor in it,you can take the head(s) off as well,in fact they only want the bare body with ID plares and motor really.....they convert it to gas,claim their rebate,then have the car written off....the car can never be re-registered so off to the crusher it goes....this scheme is only for people that are game,i know of fitters doing this on quite a few vehicles,i can't work out how they are getting away with it...but they are, and it seems to be working for them,they have made quite a tidy profit,thanks to our government

[Mr_Slim]

if your looking for increased power from gas ,you won't get it.(as well as fuel economy)you will get the economy,you may gain 0.5 % power even with fine tuning.
the government are offering this rebate in the hope everyone will take advantage of it,as soon as the numbers suit the government you watch,the price of petrol will fall remarkably..also there is a scheme going on out there... if someone offers you more than market value for your car,they say you can take anything you want off it,but you must leave the motor in it,you can take the head(s) off as well,in fact they only want the bare body with ID plares and motor really.....they convert it to gas,claim their rebate,then have the car written off....the car can never be re-registered so off to the crusher it goes....this scheme is only for people that are game,i know of fitters doing this on quite a few vehicles,i can't work out how they are getting away with it...but they are, and it seems to be working for them,they have made quite a tidy profit,thanks to our government

not sure about the price of petrol being dependant on the amount of LPG conversions being done. Petrol cars would still out number LPG by probably 10,000 to 1. The government doesn't want to stop selling petrol, because they make way too much money off it. just like cigarettes.

in saying that, im not sure why they offer the rebate then. is it because they have a social conscience and want to do something for the environment? (LOL!) or is it just to be SEEN to be doing something for the environment?

Either way it doesn't matter to me, i need the conversion ASAP. if i get a boost in power, thats just a bonus. if not, well thats still ok because i just need the spare cash (and before someone says "yeah but you spend so much up front etc" - i do at least 800km a week so i make back the money very quickly) and at only $700, its cheap as.

in regards to doing a conversion, getting the coin and selling the car, it is technically possible, however a registered owner can only do it once every 3yrs. so to make it work you would have to buy a car, register to yourself, and do conversion, then sell. next car, you'd have to register to someone else, convert and sell. and so on. so it is possible, but eventually you'd run out of friends who a) are willing to claim the responsibilities of owning a car they don't actually own, and b) are willing to forgo the opportunity to get a conversion on a car they do actually own for the next 3yrs.

[samuels]

not sure about the price of petrol being dependant on the amount of LPG conversions being done. Petrol cars would still out number LPG by probably 10,000 to 1. The government doesn't want to stop selling petrol, because they make way too much money off it. just like cigarettes.

in saying that, im not sure why they offer the rebate then. is it because they have a social conscience and want to do something for the environment? (LOL!) or is it just to be SEEN to be doing something for the environment?

Either way it doesn't matter to me, i need the conversion ASAP. if i get a boost in power, thats just a bonus. if not, well thats still ok because i just need the spare cash (and before someone says "yeah but you spend so much up front etc" - i do at least 800km a week so i make back the money very quickly) and at only $700, its cheap as.

in regards to doing a conversion, getting the coin and selling the car, it is technically possible, however a registered owner can only do it once every 3yrs. so to make it work you would have to buy a car, register to yourself, and do conversion, then sell. next car, you'd have to register to someone else, convert and sell. and so on. so it is possible, but eventually you'd run out of friends who a) are willing to claim the responsibilities of owning a car they don't actually own, and b) are willing to forgo the opportunity to get a conversion on a car they do actually own for the next 3yrs.

i have nothing against gas it all comes down to personal preference,as in your case,in regards to this scheme that is going on,here on the li'l island below you the registered fitters have many friends,they don't register the car in their name,it's left in the friends name,and that friend gets a cut...or slice of the pie as they aren't interested in actually converting to gas,instead they want to make a quick buck on a clunker,we can own as many cars as we want,now as for the conversion to gas with government assistance i don't know if it's a one off subsidy or they assist with every vehicle you have.
up to half of the $2000 assistance,then what you make off the parts...I.E mags,tyres etc,etc,....makes for a nice tidy profit allround

[Mr_Slim]

i have nothing against gas it all comes down to personal preference,as in your case,in regards to this scheme that is going on,here on the li'l island below you the registered fitters have many friends,they don't register the car in their name,it's left in the friends name,and that friend gets a cut...or slice of the pie as they aren't interested in actually converting to gas,instead they want to make a quick buck on a clunker,we can own as many cars as we want,now as for the conversion to gas with government assistance i don't know if it's a one off subsidy or they assist with every vehicle you have.
up to half of the $2000 assistance,then what you make off the parts...I.E mags,tyres etc,etc,....makes for a nice tidy profit allround

agreed. sometimes makes me wish i learned a trade!

but yeah back on the subject of LPG conversion, it looks as though std. dual fuel appears to be the way to go (for all models up to about 2005) and the theory of getting 10-15% more power out of gas due to higher octane appears to be a myth - only works in theory, but in practice gas provides lower engery levels therefore lower power.

however i suspect that you should still recieve the higher level of smoothness you get from higher octane fuel. notice how much smoother your car runs with Vortex / Optimax?

And ever notice how incredibly smooth a cab with 600,000km on the clock is? i'm tipping the gas has something to do with it...

[samuels]

agreed. sometimes makes me wish i learned a trade!

but yeah back on the subject of LPG conversion, it looks as though std. dual fuel appears to be the way to go (for all models up to about 2005) and the theory of getting 10-15% more power out of gas due to higher octane appears to be a myth - only works in theory, but in practice gas provides lower engery levels therefore lower power.

however i suspect that you should still recieve the higher level of smoothness you get from higher octane fuel. notice how much smoother your car runs with Vortex / Optimax?

And ever notice how incredibly smooth a cab with 600,000km on the clock is? i'm tipping the gas has something to do with it...

ohhh theres no doubt that there would be increased smoothness with gas.... no dirt in fuel etc,etc,taxis do very well on gas, but i'm a firm believer of dual fuel,although i haven't enough experience in the gas field,but as a motor mechanic (retired) i have to look at both sides,the pros and cons,but it's the same with everything theres pros and cons,as i said it all comes down to personal preferences,and if the homework is done,and it actually does suit your needs,thats all thats needed....

[defa]

on an injected car you can have it running like a straight gas car. those gas research throttle body's can be put in place of your throttle body. then when you want to run petrol you still can. i may be wrong but as far as i know you can do this.. much beter idea than running a donut.
and as for getting more power out of gas. haven't gas research made good power gains out of gas. and proved it over and over. or is that not right

[samuels]

on an injected car you can have it running like a straight gas car. those gas research throttle body's can be put in place of your throttle body. then when you want to run petrol you still can. i may be wrong but as far as i know you can do this.. much beter idea than running a donut.
and as for getting more power out of gas. haven't gas research made good power gains out of gas. and proved it over and over. or is that not right

it hasn't really got the ignitability as petrol,sure it goes bang...lol....but not as much as petrol,gas is quite technical really, but me personally,you don't get much more oomph from gas

[Mr_Slim]

so should i be going with the std dual fuel, or this throttle body injection?

the Gas Man had never heard of throttle body injection, whereas it was suggested by the local as getting close to the power as i would get from petrol.

the local was $2600, and the Gas Man was $2700.

Is there any difference between Throttle body injection and normal lpg? sorry, i just don't know that much about it lol.

[defa]

you can get gas throttle bodys made by gas research, or you can use the ol' donut in the intake tube. which i am not a fan of. i had one on a carby on my old valiant. got averagel power, but it was so cheap to run.

[Cheap6]

More pieces of string. As I suggested though, both the components and installation are important.

I am aware of one (there may be more) type of throttle body gas injection. Although, what one person may refer to as 'injection' may differ from another's. More info needed.

Without optimising an engine for gas there are losses (small) in introducing a restriction into the intake path with a carb or, worse, gas ring, and the LPG, as a gas, displaces more air than does a mist of (mostly) liquid petrol.

Optimising, beyond ignition timing, costs lots of money for not much gain (replacing pistons. camshafts etc,). Ideal fuel mixtures on gas, even for maximum power, (and emissions) are pretty much fixed, it is how closely that ideal is approached that varies. (You won't pick up lots of power by running richer.)

The energy content of the fuel doesnt have much to do with it, beyond stoichiometry (air fuel ratio) influencing the amount of energy that can be released for a given amount of air.

The performance drop on a VP on LPG from a contemporary road test of the factory approved system was 16.7 vs 17.1 secs. 400m.

When looking at the economics of converting (pay back) you should be allowing for 1.4X increased fuel consumption on a volume basis eg. LPG at 50cpl is the equivalent of petrol at 70 cpl.

If looking at changing to the VS to make the conversion worthwhile, consider the cost of looking for another car, rego transfer and fixing all the little things wrong with a 'new' used car. That could easily be $5-600.

Converting three cars should be worth some sort of fleet discount I think

Speculating on the Govts motivation for the subsidy:

1) It helps suport the local manufacturers, mostly of large cars where converting is of greatest benefit.

2) It was seen to be doing something about high petrol prices.

3) The money is being spent in Australia, in a service industry, with at least some of the products (tanks for eg.) used being made here = helps the economy.

4) It provides a ready market for the (largely unwanted) heavy components from all that natural gas we are exporting to China.

[greenfoam]

Gas research carbies are the way to go, I know people with these on 5 litres and they swear there is no noticable loss of power switching to gas from petrol. You really need a dual throttle setup on a good 5 litre because they don't make a big enough carby to run only one. But just one of the bigest they make will be fine on a V6

[Mr_Slim]

thanks for that Cheap6. i know many of my questions have been a bit open ended! Thanks for answering anyway!

I won't be upgrading to the VS, i love my VP too much and like you said, upgrading would defeat the purpose of going with Gas in the first place.

I'm going to call the Gas Man in sydney to get it installed. Another question - if you go to install a new memcal on your car, its best that you've got all your mods done first, as to maximise the output of the memcal. When they convert my car to LPG, they will need to edit the memcal obviously - so it is better that i have all the mods done to my car first (extractors, V8 throttle body are the only other things i wanted to do) before i get the LPG conversion?

Gas Man said he would modify the air-fuel mixture based on my mods. Is the memcal reprogramming done by the LPG guys (The Gas Man) different to what say Dr Bob could do?

Thanks again guys - i know i am asking very basic questions, but this was not in any previous threads really, so hopefully this will help more people in the future!

[Cheap6]

Probably best to ask The Gasman exactly what they do (and what system/components are used). The LPG fuel mixtures will be determined (actually fine tuned over a mechanically determined base level on simpler systems) by a stand alone computer though, separate to the factory ECM, which will still be used for ignition timing only. The LPG computers vary from having no external adjustment (they just chase an O2 sensor voltage) up to a degree of self learning programming.

You may, if you have not done so already, let them know that your car is a Calais, not a Commodore and therefore has IRS, as there is an extra box section for the IRS subframe which two of the mounting holes for the bracketed APA tanks must pass through. (Assuming they use the APA tank, which is the most common). I don't think it will be any great drama because the holes are in the same location as two of the light duty tow bar holes, but will require a different backing plate and the addition of anti crush tubes (same as a tow bar).

[Mr_Slim]

I just booked the car in for the LPG conversion. Costs $2600 for throttle body injection. Basically the deal is as follows:

- Tank in the boot, just up the top
- Switch on the dash to flick between gas and petrol
- LED display of gas in tank
- Apparently gets slightly less kms than petrol. figures quoted were 450km per tank of gas
- Slightly less power, but apparently not enough to notice (but this "not enough to notice" may be to someone who doesn't pay attention)
- Takes approx. 1 week to install
- Different system needed for manual gearbox vs auto gearbox
- Essential that you tell them if you have traction control - apparently a spark set off if you have TC means a different computer is needed, otherwise KABOOM!
- Need to have at least 1/2 tank of petrol (pref premium) in the car at all times, and should be run on petrol from approx. 30mins a fortnight, just to keep everything going.
- systems can take anywhere from 1wk to 3mths to order in, and the waiting list for installation can be about the same (i'm getting it done in 2 weeks from Tyrepower, it was 3mths wait at the Gasman)
- Commodore systems are a lot quicker to order in. Don't expect to get your Ferrari converted anytime soon
- LPG is currently sitting at between 48c - 55c per litre. Petrol is sitting at 1.25 - 1.35 per litre.
- excise on LPG is due to come in 2011, so plenty of time to recover the costs of the conversion, assuming you do a decent amount of driving.

This is all according to Tyrepower in Campbelltown, and the Gasman in Sydney, who i got information from.

Another point of note - a 2.5inch exhaust, CAI and K&N - total cost $600, saving = 1.5L/100km or $1.75 per 100km. LPG Conversion total cost $600 ($2600 - $2000 rebate), saving of 70c per litre or $6 per 100km.


The day after i get it all installed, i will post up performance figures (rough estimates anyway) and let you all know how it performs, once and for all. My figures will obviously be different to others, especially as my car is manual. If anyone on here with an auto has done the conversion, performance figures would be great.


Mods - maybe make this thread a sticky, seeing as it pretty much covers all the questions needed to be asked / answered? Or possibly someone (maybe even me) can re-write the thread and post up? Pretty useful information to questions asked quite a lot.


Thanks guys, hope this info helps if you're considering getting the conversion done