Straight Gas Thoughts

[MyGQ]

Hi Guys

Well with the price of Petrol these days, i can't ever see myself running my Patrol on Petrol again, and since i ain't touring in it, i am looking at setting up the unit for straight gas

So what i want to do is get rid of the carby all together, simply because they are pretty crap for the LPG setup (damm vacumme Secondary doesn't work).

I know i need to shave the head and get a Gas Cam (well thats the best way to get more power) but i was thinking that another way to increase air flow as well as prevent any escaping gas (it happens on carbys) would be to bolt on a EFT throttle chamber and use that as the air system. If i am right the Butterfly is in the upper part near where the pipework is utilux clamped on, this is where i would have my LPG ring setup to introduce the gas to the air mixture.

Is this possible to do? would it work? not interested in the Petrol side, the Injectors can just sit there and look pretty.

Also this would make it alot easier fittign a TD42 Turbo system on as the plumbing is already there, just need to make the pipe connect to the unit.

a fully sealed system would be good for adding a Snorkle

If anyone has heard of guys doing htis or any places that do it, can you please let me know where to get the parts and an aprox cost (gas cam, head shaving, EFI chamber and any extra parts i will need)

Thanks guys

[bru21]

I would fit au falcon multipoint gas injection from the factory gas only falcons. that way you might even get increased power, better economy, etc. should fit straight on.

but i never do things the easy way

cheers bru

[MyGQ]

Ok will look into that

so thats just the chamber is it?? cause mine is a Carby model and i won't want to install computers and sensors on my setup

[airborne]

I have run many turbo LPG systems, the injection of LPG is becoming much more popular these days and can be either liquid injection or vapour injection.

However like you have said it needs a ECU to control it, I feel that the less electrical systems the more reliable the whole car is, one benefit of LPG is the system is simple, people go and run LPG injection making the system more complex.

I am unfamiliar with the engine you have, but the basics should still apply, you have three choices.

1.simple ring mixer, fitted to carb or throttle body
2.Impco mixer, fitted to carb or throttle body
3.Gas Reaserch Australia throttle body/mixer

From least expensive to most expensive, Impco is probably my choice for a street car.

On a ford 250 we ussually swap the carb intake for a fuel injected one, they work very very well with gas.

Here is some info I posted on another site, it may not all apply to you but here it is anyway:

"GRA isn't good for whatever you want from it, it must be sized accordingly, there are 5 different sized mixers and the larger few will require multiple converters to supply enough gas to equal there rating.I think they go 350, 400, 440, 480, 510.

Impco has a 425, and some smaller ones, 225, theres probably more.

The benefit of Impco is most tuners can handle it, GRA requires different and sometimes custom fuel metering rods, and jets also. So

GRA is more sensitive to barometric pressure, and the tune will change with altitude, in theory it should also effect impco but I guess theres just more people running fast GRA cars so more people notice it.

GRA requires special springs inside the converter, the converter must be mounted horizontal. Impco parts are cheaper and it is generally accepted that there converters can be mounted however you want, although horizontal would be safest.

Impco has/can use a model E converter, they are bigger than the typical B2, B2 is rated at a maximum 296HP of gas delivery. I don't know what the model E would deliver but its bigger, maybe another 30-50HP???

You can use multiple lockoffs to improve flow, and I think a VFF30 flows a fair bit and is a refferenced reg, the others are not refferenced. I don't know if that helps flow or whatever. running one lockoff per converter would be ideal.

One small tank will not supply much gas for extended periods, the pressure drops inside the tank and then the flow also drops and you go lean, the only remedy to that is big tanks and more of them. The excess flow valve can also trip if the pressure drops causing lean out.

Both systems will need balance lines to each converter. Using a metal lid is safest option.

If you go to the strip you will find most fast cars that run LPG use GRA products, thats not to say Impco or others doesn't work but generally speaking GRA is performance oriented. There are many 10 second 6 bangers using a single GRA 510, with two B2's.

Since you have a V8, packaging the system will probably determine what you go with, the GRA stuff is basically like a throttle body on its own, it is easily adapted onto existing manifolds in place of the original t/b. The impco stuff would require a seperate t/b and is a little more bulky.

One nice feature of the GRA is the partial throttle jets that help deliver fuel in the same manner as an accelerator pump, it helps reduce the common lean backfire you sometimes get with LPG, if you floor it suddenly. Having said that I personally found GRA used more fuel, but made more power, A single 425 Impco on a 5.8lt engine will run out of puff up top, usually around 45-4800rpm. My GRA twin setup pulled 6000+rpm easily. Running two 425's would be good but you would have poor low RPM mixture control. The same goes for GRA if the mixers are too big the vacuum signal that pulls the gas from the converters will be weak at low rpm.


Gra mixers are about 440$ each, The GRA B2's(they are just std B2's but with a spring kit) are about 176$ each, metal lids are 30$ each."

That was from a ford site, and your application probably doesn't require as much HP as that one.

I have very little experience with ring style mixers, but I know that they are tuned to some extent simply by selecting the correct venturi size for the application, they are cheap and effective, but in every single case the engine will produce less power than without the ring on, simply because it is creating a restriction, and it needs that restriction to pull the gas from the converter, hence the reason why many people don't like ring mixers.

The Impco and GRA will generally give a better result.

Having said that the ring mixer is the most simple solution and sometimes if power isn't an issue then it can work well for minimal cost.

Cheers.

EDIT-I just thought some of that may help shed some light on the subject as you mentioned turbocharging the engine and it would be best if you kept that in mind when setting it up initially.

[airborne]

I have read your post again.

The octane rating of LPG is no way even close to what it was 10yrs ago. I usually think around 95 to 104 is about the best you will get from pump LPG, they add a lot more butane than they used to. Propane is what has a higher octane and is what is used in the US, we however get a dodgy mix that can be any ratio the petrol companies decide to use, usually as much butane as they can without shit freezing over, so in winter they usually use less butane.

SO you should aim for a compression ratio of about 10 to 1 for an iron headed engine maybe 10.5 to 1 with alloy head. Before anyone chimes in and tells me you can run shitloads more compression, you must consider you have have an engine destined for daily driving and will most probably use a camshaft profile that delivers a high dynamic compression, big revvy engine with a wider lobe seperation and large duration will have a lower dynamic comp and can get away with 11+++ to 1 comp. HOWEVER you mentioned fitting a turbocharger, so your comp ratio needs to be lower, depending upon how much boost you want to run.

Aim for 9.0 to 1 and run about 8psi, that is a very safe level and will deliver great performance and lag will be almost unnoticeable, there will be more room to move as well if you decide to turn up the boost later on.

What is the std comp ratio??? for your engine.

Speak to "WADE CAMS" they have done a lot of work with gas, they helped design the GRA Voodoo series of cams.

[MyGQ]

My engine is a 4.2L Inline 6 engine

It maxes out at 4500RPM (Redlines) and goes to a max or afound 6000RPM on the dial

I am simply looking at improving economy as well as making it dedicated gas.

[airborne]

impco 425 sounds like it would suit.

what exactly do you wan't to know?

any system will work, just some are more suited at different things.

[jessie928]

i would reccomend teh 300a series mixer for a standard 4.2, the 425 is a little to big.

Jes

[V8Patrol]

I have read your post again.

The octane rating of LPG is no way even close to what it was 10yrs ago. I usually think around 95 to 104 is about the best you will get from pump LPG, they add a lot more butane than they used to. Propane is what has a higher octane and is what is used in the US, we however get a dodgy mix that can be any ratio the petrol companies decide to use, usually as much butane as they can without shit freezing over, so in winter they usually use less butane.

Curent ratio is 5its of Butane per 85 of Propane & 1 lit of H2O

Worst LPG comes from "Safeway / Woolworth" fuel sites where the ratio can at times reach up to 10% butane.

Although the "bad mixes" arent generally noticed in short driveing conditions thye are most certainly noticable when doing a log haul...... lack of engine power, poor acceleration, hard starting when hot..... these symptons generally appear once the tank is a 1/4 full or less simply because tha butane has seperated in the tank and is largely what is left to "burn".

I recently dumped 8 lits of butane / H2O from a tank that had this shyte quality LPG in it (72 lit tank ) and I'm not the only one seeing moreof this stuff comming through the pumps. Local LPG fitter is vacumeing 3 - 4 tanks a week in recent times......... oddly enough the problem has only surfaced since a new "Safeway" outlet opened up locally


For those that dont know butane can be poured into an open bucket and it "looks" just like water would....... only with a very slight yellow tinge. A bucket holding say 2 lits will take an afternoon to vapour off at an ambient temp of around 20degrees......... thats why its shyte in ya car system.

Kingy

[CRUSHU]

I would fit the EFI manifold, and block off the injector holes with welch plugs. I would use the Impco 425, as they are more of a carby than any of the other devices. An Impco 225 just lets the gas flow, whether you are at idle or flat out.

[airborne]

300A would work, I just find the 425 better to tune.

[Big Red Toy]

my new patrol has a gas research system on it, i've only driven it a total of perhaps about 10k's but good damm does it pull hard

[airborne]

yeah I've had a few of there setups, they work very well, sometimes hard to tune but very good power.

[77F1004WD]

I have read your post again.

The octane rating of LPG is no way even close to what it was 10yrs ago. I usually think around 95 to 104 is about the best you will get from pump LPG, they add a lot more butane than they used to. Propane is what has a higher octane and is what is used in the US, we however get a dodgy mix that can be any ratio the petrol companies decide to use, usually as much butane as they can without shit freezing over, so in winter they usually use less butane.

Curent ratio is 5its of Butane per 85 of Propane & 1 lit of H2O

Worst LPG comes from "Safeway / Woolworth" fuel sites where the ratio can at times reach up to 10% butane.

Although the "bad mixes" arent generally noticed in short driveing conditions thye are most certainly noticable when doing a log haul...... lack of engine power, poor acceleration, hard starting when hot..... these symptons generally appear once the tank is a 1/4 full or less simply because tha butane has seperated in the tank and is largely what is left to "burn".

I recently dumped 8 lits of butane / H2O from a tank that had this shyte quality LPG in it (72 lit tank ) and I'm not the only one seeing moreof this stuff comming through the pumps. Local LPG fitter is vacumeing 3 - 4 tanks a week in recent times......... oddly enough the problem has only surfaced since a new "Safeway" outlet opened up locally


For those that dont know butane can be poured into an open bucket and it "looks" just like water would....... only with a very slight yellow tinge. A bucket holding say 2 lits will take an afternoon to vapour off at an ambient temp of around 20degrees......... thats why its shyte in ya car system.

Kingy

Hi Kingy, i know you are very knowledgable with LPG, but after recent research, i found most suppliers quoting 50/50 mix of butane/propane or 60/40. See the following site
http://www.bp.com.au/products/LPG/lpg_product_info.asp
Scroll to the bottom,
Also this is a reply i got from Caltex, re the Vitalgas they use at some outlets.

Good Morning Glen,

Thankyou for your enquiry re specifications on Vitalgas supplied to SEQ Service Stations. The data below is that of Vitalgas supplied service stations. Please note that not all Caltex Service Stations are supplied by VItalgas.

The average Lytton Refinery MON (Motor Octane Number) is approx 93 as assessed by EN589 Annex B.

RON (Research Octane Number) is not measured for auto LPG. MON is a more relevant measure for LPG and if the MON is compliant, then the RON will be sufficient. For this reason RON is not a specified performance criteria for LPG. This is in line with European practice.

For general information, Lytton auto LPG with a MON of approx 93 will have a RON>100.

The blend is generally 60/40 Propane/Butane respectively.

This gives a conversion of litres/tonne of 1885. Given this the kg/l density is generally 0.53.


Hope above was helpful.

Kind regards

Shanaz Khan


Back on topic, i plan to do exactly as you have desribed. I had a 88 carby GQ, i have put a EFI manifold on, and i'm using a OHG x-450 mixer. I have just ordered my laser cut flanges and think wall SS pipe to make my manifold. I will be using a TO4E, roller, 60-1 front and p-trim rear, 1.00 Ar. I want 300RWHP and excellent mid range boost. I won;t be using a Intercooler, but will be using water injection.
I wouldn't recoemend using a system designed for a TD42, the turbo will be way too small for a Petrol/LPG powered car.

I have a lot of advice that was given to me from a very knowledgable source, if your interested, i'll copy it here, but be warned, it is long!
I have since fitted a snorkle to my car-as cold air induction, turbo will be fitted before x-mas.


Sorry for the long post.
Glen

[V8Patrol]

Your right Glen
I was looking at the ratio of what was left in the tank as "useable LPG", its that ratio that is higher than it should be..... 90 lit tank producing a "waste " of 7 - 9 lits of butane / water mix.

I've even noticed that the household cylinders are containing much more butane in recent ........ its not vapourising off fast enough to maintain the hotwater service supply needs so ya change cylinders and when ya are doing the swap ya can feel the liquids weight still in the cylinder.


At least I've found a couple of uses for the stuff ...... excelent weed killer ..... empty the tank / cylinder into a bucket and throw bucket ( like ya would if it was water ) at the weeds.......
Cape weed has a waxy leaf that protects it from the UV rays.... the butane burns off the wax.... weed dies !
Excelent Bullant nest distroyer too

[airborne]

Thats what i thought 50/50.

That OHG-450 looks easy to package, is it 450cfm?