Hi all,
Hoping someone can shed some light on a conundrum I'm battling with atm .... basically thinking about doing a custom LPG job (yeah ... I'm joining the fumigation brigade - or thinking about it!)
I'm confused as to the types of mixers and converters available - since I'm running TD42-T, I need a mixer with a balance port since I'll be injecting the gas post turbo, and run the balance port to the manifold to sense boost pressure.
- How do I tell if a converter has a balance port?
- Do ALL converters come with balance ports and I just don't know it?
- Positive pressure or negative pressure?
- How do I tell which is which (as everyone except for Impco seem to keep this info a secret - MGA / OMVL etc).
- Does this affect the potential gas flow?
- Does a pos/neg type have to be matched to a particular type of mixer?
- Does a converter have to be matched to a particular type of mixer?
- Do I need a particular size / type of converter?
- Is there such a thing as too small / too big for my application?
- Can you have such an available gas flow that it is impossible to turn it down?
- What is a priming solenoid and why do I need one?
- Should I go for a complex converter with idle control valve?
- Do I need to inject gas at idle? I would think perhaps not .... but open to suggestions on this one ....
As for control - I was going to try and get my hands on a GasResearch mixer control valve - specifically designed for this sort of thing (diesel/lpg)
- or is there something else available that I'm missing here?
In terms of mixing - I was just going to go for a simple, non-adjustable venturi type mixer and let the control valve do all the work in terms of regulation / control ... any cons to this approach?
Any recommendations on brands / type of converters or mixers for this application? Either in terms of suitability or reliability ....
Thanks! And sorry for all the questions!
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LPG mixers and converters - how to size / match them?
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LPG mixers and converters - how to size / match them?
If it's worth doing - it's worth doing to excess ...
I'm guessing that if you have to ask so many questions about how and what to do, then it might not be particularly safe for you to do anything... There are accredited installers that have the authority to do the job safely, and provide all the paperwork to keep your vehicle safe and your arse out of court.
Seriously, if the vehicle is going to be used on road with people and traffic all around, you are going to get your (and your family's) arse burned if there is EVER and accident you are involved in. One of the first things the insurers will be looking at is compliance with all the regulations, and a backyard LPG setup is going to make you technically unroadworthy, pushing liability for all damage and personal injury onto you. (not to mention other charges such as driving an unroadworthy vehicle, etc) For a road going vehicle it is not worth the gamble.
Missing something important during the backyard installation, putting you and your family at great personal risk is another thing to be considered.
For a buggy then go for it BUT WITH CARE AND DECENT GUIDANCE (still going to be ppl around, and you not more than 2 feet from the bottle and plumbing)...
Seriously, if the vehicle is going to be used on road with people and traffic all around, you are going to get your (and your family's) arse burned if there is EVER and accident you are involved in. One of the first things the insurers will be looking at is compliance with all the regulations, and a backyard LPG setup is going to make you technically unroadworthy, pushing liability for all damage and personal injury onto you. (not to mention other charges such as driving an unroadworthy vehicle, etc) For a road going vehicle it is not worth the gamble.
Missing something important during the backyard installation, putting you and your family at great personal risk is another thing to be considered.
For a buggy then go for it BUT WITH CARE AND DECENT GUIDANCE (still going to be ppl around, and you not more than 2 feet from the bottle and plumbing)...
George Carlin, an American Comedian said; "Think of how stupid the average person is, and realise that half of them are stupider than that".
Re: LPG mixers and converters - how to size / match them?
Ok I can help on a few things but not all
- How do I tell if a converter has a balance port?
Normally they have a vent or balance port on the other side of the largest diaphram - I know nearly all omvl and landi converters have one - if they have a hole with a small elbow or tube attached and you can see the diaphram down that hole it is a balance port. (best of my knowledge)
- Do ALL converters come with balance ports and I just don't know it?
Not sure as I said - every OMVL I have seen does and the 4 landi converters I own have one
- Does a pos/neg type have to be matched to a particular type of mixer?
Yes but I don't now how or understand how
- Does a converter have to be matched to a particular type of mixer?
Some yes some no, IMPCO does most other standard type can be mixed and matched
- Do I need a particular size / type of converter?
Yes
- Is there such a thing as too small / too big for my application?
Definately - I know that when you converter is too large it is neraly impossible to tune it effectively - there is not enough ajustment in the device to achive the right result.
- Can you have such an available gas flow that it is impossible to turn it down?
Yes
You need to go for a drive and speak to the guys at progas in Brizzy they are ususally more than happy to help - they have always been very good to me.
Tom
- How do I tell if a converter has a balance port?
Normally they have a vent or balance port on the other side of the largest diaphram - I know nearly all omvl and landi converters have one - if they have a hole with a small elbow or tube attached and you can see the diaphram down that hole it is a balance port. (best of my knowledge)
- Do ALL converters come with balance ports and I just don't know it?
Not sure as I said - every OMVL I have seen does and the 4 landi converters I own have one
- Does a pos/neg type have to be matched to a particular type of mixer?
Yes but I don't now how or understand how
- Does a converter have to be matched to a particular type of mixer?
Some yes some no, IMPCO does most other standard type can be mixed and matched
- Do I need a particular size / type of converter?
Yes
- Is there such a thing as too small / too big for my application?
Definately - I know that when you converter is too large it is neraly impossible to tune it effectively - there is not enough ajustment in the device to achive the right result.
- Can you have such an available gas flow that it is impossible to turn it down?
Yes
You need to go for a drive and speak to the guys at progas in Brizzy they are ususally more than happy to help - they have always been very good to me.
Tom
"It was just an ordinary day, and you saw them. There were guys in their Porsches, "Look at me in my Porsche, ha ha!" and they were overtaken by a van. Driven by a girl!"
DAMKIA:
It is not illegal nor non-roadworthy to install a custom gas system on a vehicle. It is not illegal for me to design a metering / mixing system system based around AGA approved parts. I would like to do it myself as there are very few "off the shelf" installs available for this sort of system - I don't agree with some of the mixtures and theories of operating of the systems which are available and hence want to design it myself.
What I do not know is how the various parts all match up in terms of flow rates etc .... the best way to find stuff out is to ask questions ...
There is nothing illegal about me making my own intake to suit a prebuilt venturi, nor is there anything illegal or unsafe about me purchasing autogas parts.
There is nothing illegal about me mounting a converter or venturi or tank. It is illegal for me to do the pipework - even if it is to AS1425:2003 - as I am not a licenced gas fitter.
The appropriate parts of the system will be done by an accredited gas shop and a compliance plate attained. Although I intend on adjusting the mixtures and tuning it myself.
If I was asking quesitons like:
- Can I use a rusty BBQ gas bottle instead of a stamped autogas tank?
- Is it ok if I use garden hose to pipe the liquid gas into the converter?
- Do I have to bolt the cylinder down or can I just let it roll around in the back?
Then I would be concerned ...
RAGINROVER:
Thanks very much for the reply - much appreciated! I'll go down and have a yarn to Pro Gas and see if they can shed some light on it!
It is not illegal nor non-roadworthy to install a custom gas system on a vehicle. It is not illegal for me to design a metering / mixing system system based around AGA approved parts. I would like to do it myself as there are very few "off the shelf" installs available for this sort of system - I don't agree with some of the mixtures and theories of operating of the systems which are available and hence want to design it myself.
What I do not know is how the various parts all match up in terms of flow rates etc .... the best way to find stuff out is to ask questions ...
There is nothing illegal about me making my own intake to suit a prebuilt venturi, nor is there anything illegal or unsafe about me purchasing autogas parts.
There is nothing illegal about me mounting a converter or venturi or tank. It is illegal for me to do the pipework - even if it is to AS1425:2003 - as I am not a licenced gas fitter.
The appropriate parts of the system will be done by an accredited gas shop and a compliance plate attained. Although I intend on adjusting the mixtures and tuning it myself.
If I was asking quesitons like:
- Can I use a rusty BBQ gas bottle instead of a stamped autogas tank?
- Is it ok if I use garden hose to pipe the liquid gas into the converter?
- Do I have to bolt the cylinder down or can I just let it roll around in the back?
Then I would be concerned ...
RAGINROVER:
Thanks very much for the reply - much appreciated! I'll go down and have a yarn to Pro Gas and see if they can shed some light on it!
If it's worth doing - it's worth doing to excess ...
Why does LPG freak people out so much ... no one flinchs when someone says they are converting to EFi.. with a series of aftermarket parts, pumps etc etc ..
LP gas systems have several inbuilt failsafes, the tank is tough as teak ..
LP gas systems have several inbuilt failsafes, the tank is tough as teak ..
" If governments are involved in the covering up the knowledge of aliens, Then they are doing a much better job of it than they do of everything else "
Probably a lot MORE failsafes love_mud - e.g. fuel lines are solid copper flares, no flex / rubber ... check valves everywhere ... 2 safety solenoids.
And the gas flow out of the converter is pretty minimal if you have a low side leak ...
I guess the fear is the secondary stored energy - begin 350 odd psi of liquified fuel which if (on the off chance) you spring a leak you have no real control over the flow. Leak in a fuel line? No worries - a bucket will fix that up! Leak in an LPG tank? Forget it ...
But then again I'd rather have LPG leaking into my engine bay than a Walbro Hi-Flo fuel pump spraying fuel into it @ 150psi through a 1/2" hose!
Risks with either I guess!
And the gas flow out of the converter is pretty minimal if you have a low side leak ...
I guess the fear is the secondary stored energy - begin 350 odd psi of liquified fuel which if (on the off chance) you spring a leak you have no real control over the flow. Leak in a fuel line? No worries - a bucket will fix that up! Leak in an LPG tank? Forget it ...
But then again I'd rather have LPG leaking into my engine bay than a Walbro Hi-Flo fuel pump spraying fuel into it @ 150psi through a 1/2" hose!
Risks with either I guess!
If it's worth doing - it's worth doing to excess ...
boils down to one thing. You can't see a leak of gas, you can see petrol.spannercrab wrote:Probably a lot MORE failsafes love_mud - e.g. fuel lines are solid copper flares, no flex / rubber ... check valves everywhere ... 2 safety solenoids.
And the gas flow out of the converter is pretty minimal if you have a low side leak ...
I guess the fear is the secondary stored energy - begin 350 odd psi of liquified fuel which if (on the off chance) you spring a leak you have no real control over the flow. Leak in a fuel line? No worries - a bucket will fix that up! Leak in an LPG tank? Forget it ...
But then again I'd rather have LPG leaking into my engine bay than a Walbro Hi-Flo fuel pump spraying fuel into it @ 150psi through a 1/2" hose!
Risks with either I guess!
You want to see some "gas" explosions, look into the explosions that can occur on boats with their bilges full of old petrol fumes..... now imagine a boot full of the same in most passenger cars. A spark from a faulty tail light is all it would take.....................
George Carlin, an American Comedian said; "Think of how stupid the average person is, and realise that half of them are stupider than that".
This is starting to get a little off topic, but anywayz ...
True you can see petrol, but the ethyl mercaptan odouring agent in LPG indicates a leak long before it reaches critical (explosive) mixture - the smell is well and truly nauseating by the time a combustable mix is reached. LPG is easily distingishable at 15 times less than the minimium flamability by volume.
Loss of the low side feed hose from the converter would result in nothing more than a sudden loss of power - LPG has a very high ignition point (540degC) and would be very unlikely to ignite even in the confines of a (very well ventilated) engine bay.
The same thing in an EFI petrol vehicle would more likely than not result in a major engine bay fire - Petrol ignites at 220degC - the exhaust headers are more than hot enough to supply a sufficient ignition source.
LPG also needs more of a vapour concentration (2.1%) as opposed to only 1.4% required for petrol ignition.
LPG tanks are vented outside of the vehicle via their subcompartment, in case a leak did occur - which would more than likely be either the valves themselves or the threads securing them in place (given the strict 10 year pressure test / inspection intervals - this is unlikely to be a fault with the tank itself) - the excess LPG is vented outside the vehicle.
To install a tank without a vented subcompartment in and enclosed cabin is highly illegal.
Any fire or explosion in a vehicle would be bad, of course, but this could be caused equally as easily by either petrol or LPG ...
True you can see petrol, but the ethyl mercaptan odouring agent in LPG indicates a leak long before it reaches critical (explosive) mixture - the smell is well and truly nauseating by the time a combustable mix is reached. LPG is easily distingishable at 15 times less than the minimium flamability by volume.
Loss of the low side feed hose from the converter would result in nothing more than a sudden loss of power - LPG has a very high ignition point (540degC) and would be very unlikely to ignite even in the confines of a (very well ventilated) engine bay.
The same thing in an EFI petrol vehicle would more likely than not result in a major engine bay fire - Petrol ignites at 220degC - the exhaust headers are more than hot enough to supply a sufficient ignition source.
LPG also needs more of a vapour concentration (2.1%) as opposed to only 1.4% required for petrol ignition.
LPG tanks are vented outside of the vehicle via their subcompartment, in case a leak did occur - which would more than likely be either the valves themselves or the threads securing them in place (given the strict 10 year pressure test / inspection intervals - this is unlikely to be a fault with the tank itself) - the excess LPG is vented outside the vehicle.
To install a tank without a vented subcompartment in and enclosed cabin is highly illegal.
Any fire or explosion in a vehicle would be bad, of course, but this could be caused equally as easily by either petrol or LPG ...
If it's worth doing - it's worth doing to excess ...
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