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calais25t

Straight LPG on an Rb25det

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I know a guy with a clapped out VL that gets pwned by my 3 Cylinder charade with my nana driving it.

Sorry about hijack fellas.

Whats goin on slaphead! pm me.

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You would have to be talking about Mr sera? (VLS_BACK)

(i go for lunch with the guy allmost everyday)  =P

Gas is fine however, The VL your talking about runs twin converters.. and runs allot warmer.

Not to mention he is running a GT40, with a 4K stall & transbrake....

All that into consideration, and it is by all means "QUICK"  but his brothers car is evidence, that you cant beat a "petrol setup" for perfomance. (james is running 9s 1/4miles)

All that aside:

-He drives the car allmost everyday.  - Thats gota be good.

-Its reasonably cheap to run

-No injectors, fuelrails, pumps, fuellines etc.  - Good $$$ saving, not to mention very tidy -underbonet & no buzzing pumps in the boot?

-EPA Legel (From a emission perspective)

-Only need a computer to fire plugs. (dont need a expensive type computer to run the motor etc.)

Good luck

Thanks for all the replies .

U make a good point that no upgrade of injectors pumps etc is needed wich works out at nearly the price fo a gas setup.

It would take a lot less than 150,000 kms to break even when u consider its $22 to fill the gas tank as compared to $55 for pulp.

Either way Im going ahead with it as I know plenty of cars running good numbers on gas.

The epa thing is a bonus, no need for a cat, charcoal canister, etc

Also no dirty injectors fuel filters etc.

In my eyes the benifits out weigh the negatives. :uh-huh:

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LPG Injection:

http://www-control.eng.cam.ac.uk/Homepage/...cts/manzie.html

http://www.abc.net.au/newinventors/txt/s1345083.htm

http://www.parnell.com.au/index.php?option...&id=3&Itemid=26  

Like I have said a few times already, all dual fuel systems on EFI cars dont use an injection system, they use a vaporised gas carburettor system.

The system I am talking about is a gas only system.

Around the time I saw it, an LPG system with dual fule was about $1000 - $1500, and the straight gas injection system was $4000.

Weather it was direct or throttle injection, I don't know and I dont care, but based on those links I have provided, direct LPG injection seems to be a very recent development. So my guess lies with throttle injection.

Even with throttle injection, a greater mass of LPG can be consumed than a standard vaporised gas carburettor system allows (in theory, and it must have been in practice too to sell for double or tripple that of a conventional system)

And yes it is a waste of money unless you do lots of km, and intend on keeping the car for a long time. Even then, it requires more maintanance, and can increase the rate of engine wear.

Not worth it in my opinion either, but definately interesting.

It does not increase engine wear. Plus u have no carbon buildup on pistons valves etc.

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It might be $22 to fill the tank but it wont last as long as the tank of petrol.

In relation to the gas injection, Gas research have a throttle body which has been around a long while that has injectors plumbed into it. My friend went with it but tuning was a nightmare so it got the toss.

Electronically controlled gas injectors with one per cylinder are a recently new thing but they are still having trouble with them freezing from what I have been told.

A guy on the R31 forums got quoted from memory $4-5k to fit the electronic gas squirters to his RB20det and they were goiing to plumb them into the inlet manifold runners but the said they could only guarantee the quoted fuel flow 80% of the time I assume because of the freezing issue.

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yeah ive been thinking about it i wana know who does gas performace tuning and what a rough price for the conversion would be... if ne one can help me plz PM

ring gas research in dandy.. iv seen them do vlt's that were quick

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Thanks for all the replies .

U make a good point that no upgrade of injectors pumps etc is needed wich works out at nearly the price fo a gas setup.

1. It would take a lot less than 150,000 kms to break even when u consider its $22 to fill the gas tank as compared to $55 for pulp.

2. Either way Im going ahead with it as I know plenty of cars running good numbers on gas.

3. The epa thing is a bonus, no need for a cat, charcoal canister, etc

4. Also no dirty injectors fuel filters etc.

In my eyes the benifits out weigh the negatives. :uh-huh:

Some counters;

1. No it won't, you will lucky to get much more than 65% of the consumption out of 1 litre of LPG compared to 1 litre of petrol. For a start 1 litre of LPG weighs ~80% of what 1 litre of petrol weighs. Then you use more LPG making the same power because of its lower calourific value, around 15% more is not uncommon. So that $22 fill is only going to take you half as far as what $55 worth of petrol will.

2. You need to do more research, they may show good max power, but their average power is way down on what an equivalent petrol engine would make. For example we have a LPG powered Ford V8 that makes 525 bhp (on the engine dyno) with an average power from 3,500 rpm to 6,500 rpm of 360 bhp. A similar engine on petrol making 535 bhp would be over 400 bhp average.

3. From my experience with the EPA you most certainly do need a cat if the car came/was complied with a cat.

4. Oh dear, you really need to have a go at cleaning the crap that accumulates very quickly in an LPG mixer. I'll take a fuel filter change every 10,000k's and an injector clean every 50,000k's thank you.

Another dissadvantage we found was the resale value of LPG powered high performacne vehicles was much lower than the equivalent petrol powered ones.

There is only one advantage and its cost over time, and even that is questionable as the time line is long. Plus there are moves (by 2008) to have LPG taxed at higher values to bring it more in line with petrol and diesel taxes. So even that advantage is subject to change within the time necessary to recover the conversion cost.

:rofl:

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Duel fuel systems don't use any form of injection AFAIK, but I have seen gas only systems that use injection. I cant remeber if it was direct injection, or throttle injection, but it was definately some form of injection.

This was in car mag 10 years ago, and I remeber them comparing size of injectors to cars standard injectors for ULP and they were considerably larger.

The setup did not allow to run ULP, it was LPG only.

Yes but your 1st post says that he would have to do something with his ecu or injectors or something....my point was that they dont use them.....and yes there is some experimental set ups that use an injector.....the guy in the factory over the road from me has been messing around with this for years.....but i think you will find that the guy that started this post plans to use a mixer type setup

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In relation to the GTI system linked earlier (and featured on the ABC's 'New Inventors'): a guy on another forum emailed the inventor to get more details about GTI systems for higher performance situations. Email response is below (most important part is bolded):

Hi Ashley,

Firstly my apologies for the delay in answering, since the program I have

had endless phone calls and over 400 emails to answer.

Thanks for your enquiry; it wasn't shown on the program but unfortunately at

the moment we do not have any retail product available. I applied to appear

on the program because I was the typical Australian inventor who could not

attract the funding necessary to commercialise the product. Since appearing

on the program, it looks as though I am making excellent progress. If all

goes well we will have commercial product available in 12 - 18 months.

Please keep an eye on the web site as we will keep you informed of our

progress and we will send email notifications to all those who have made

contact about when we will be launching the product.

The Toyota Corona is turbo charged, runs great, we are restricted to 33kW

per injector.

Best Regards

Bill Campbell

Gas Injection Technologies Pty Ltd.

Ph: +61 2 9720 1119

Email: [email protected]

Web: www.gas-injection.com

P.S. The New Inventors is an excellent show enabling people such as myself

to present our ideas to a national audience, support the ABC.

Lucien.

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Yes but your 1st post says that he would have to do something with his ecu or injectors or something....my point was that they dont use them.....and yes there is some experimental set ups that use an injector.....the guy in the factory over the road from me has been messing around with this for years.....but i think you will find that the guy that started this post plans to use a mixer type setup

I just re-read my first post and see where the mix up comes from....

When I said up-grade your injection system, I meant upgrade from the vaporised gas carburettor system.

Sorry about the bad wording. :Oops:

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It does not increase engine wear.

I know on cold starts and on idle LPG DECREASES engine wear b/c it enters the engine as a gas (not squirted as a fine mist like petrol), meaning on cold starts the unburned petrol washes down the cylinder wall diluting and removing the oil.

I have read several articles that indicate engine wear increases with LPG, but googling this topic now, I have read several sites that indicate you are correct on this one....

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I know on cold starts and on idle LPG DECREASES engine wear b/c it enters the engine as a gas (not squirted as a fine mist like petrol), meaning on cold starts the unburned petrol washes down the cylinder wall diluting and removing the oil.

I have read several articles that indicate engine wear increases with LPG, but googling this topic now, I have read several sites that indicate you are correct on this one....

I fee llike I am being too negative here, but the facts are the facts;

We just pulled down an RB30E for building into an RB31DET. After cleaning it measured up as per standard specs after 230,000 k's. The bore was perfect, no lip, score or any ovallity either. I don't thinlk LPG would have improved its wear characteristics one litttle bit.

This is not exceptional, we have done over 20 X RB30/31DET's and only the obviously poorly maintained ones (ie; oil sludge everywhere) show any bore wear. I expect that if you service your car regularly it will make far more difference to the wear than whether it runs on petrol or LPG.

:D

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No need to convince me LPG is a waste of cash, unless you drive your falcon 50,000 km a year and dont care about performance....

Although the statements I made above (taken from other resources) may be right (or may not be), they do not list what the margins are.

eg: the difference in engine wear may be so small it is negligable, but the article lists this as a positive to LPG b/c they stand to gain from it financialy.

I mentioned the cold start engine wear, b/c I was reading somewhere a while ago, that mercedes recomend you only let your engine warm up on cold starts for 30 - 60 seconds, otherwise the rich mixtures on idle wash the oil off the cylinder chambers. Then I assumed as LPG is "dry" in comparison to petrol, that engine wear on gas cold starts is reduced..... But then again, who can start their engine cold on LPG anyhow :D

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