Hey, first up, let me say that I like both gas & petrol. I run my car solely on petrol, but I may own a car that runs on gas someday. I thought that the pros & cons of gas would be an interesting topic for discussion. I will list all the pros & cons I can think of, and people can list their pros & cons, and we may have an interesting read at the end of it all. hehe.

Pros
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1) Gas is cheaper than petrol, so you will probably save yourself a few dollars.

2) Gas has a higher octane than petrol, so with appropriate tuning, you have the potential to make more power with gas.

3)If you use a straight gas setup on an EFI motor, you can do away with the ECU, allowing for wilder cams, and other serious modifications.

4) Gas is more enviromentally freindly than petrol.

5) Gas tanks are generally made of thicker steel than petrol tanks, meaning they are less likely to be ruptured in the event of an accident.

6) Gas burns cleaner than petrol, so the buildup of carbon on internal engine components will be reduced.

7) Gas will not damage a catylitic converter

8) LPG exhaust fumes do not smell as bad as petrol exhaust fumes and are less harmful

Cons
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1) A gas tank takes up a large amount of space in the boot of your car, and makes it harder to run subwoofers, and less room for luggage

2) A gas tank installation is likely to remove the mounting points for child restraints. This means that you can not safely carry and infant in the car, and possibly means the vehicle no longer complies with ADR's

3) If a gas leak occurs, it's much more likeley to explode than petrol

4) If the AFL (Automatic fill limiter) fails, there will not be enough room in the tank to allow for expansion of the gas. This may cause an explosion.

5) If the engine is left in standard tune (ie; setup for petrol, to allow efficient operation on petrol in a duel fuel setup) you will loose power when operating the vehicle on LP Gas.

6) If you have a straight gas system, and you run out of fuel, your car will need to be towed to the nearest petrol station that sells LPG.

7) If you have a duel fuel setup, and petrol is not used for a long time, damage to the carburettor/fuel injection unit may result, and the vehicle will no longer be able to operate on petrol, and performance may be degraded.

8)Gas conversions cost alot of money, so it will only pay for itself if you do alot of miles


There are sollutions to some of the above issues with LPG. It's prefrable to run the car on straight LPG, and run something like an Impco or Gas Reaseach Australia Throttle body, and this percisely meters the gas flow, and allows more efficient operation on LPG, if this is combined with correct ignition timing, and good quality LPG, You should have the sane (if not more power) than the previous petrol setup. If you run straight gas, you can also remove the fuel tank. There may be kits available to mount the LPG tank where the fuel tank was, to allow you to regain all of your boot space (I am not 100% sure on this though) If you run a duel fuel setup, you can still use a jerry can to get your car going if you run out of fuel.

I hope you guys have found my post interesting and informative. Feel Free to add to it or make corrections where nessacary.

DISCLAIMER: I dont really know all that much about LPG systems, most of this info is just what I have gathered from reading on the internet, combined with a small amount of experience I have had with owning an LPG powered Commodore (shock horror!)


Gab

Cons

The price differance is not as great these days so it takes too long for the average driver to recoop the original outlay.

Use more gas than Petrol (L per 100) affects pay back period (see above).

On Duel Fuel cars, injectors prone to fouling unless regular use of petrol is maintained. leads to expense of cleaning injectors.

Lpg is made up of a mix of propane and butane and can vary in quality significantly.

gas mixer reduces air flow into engine thus effecting performance.




After 2 previous cars on LPG (V8 XC & 6cyl EA) I have nothing to add to your Pros list.

umm NO sorry u cant do away with the ecu i mean how would the car run?
ie spark ( ef/au )
and there is the issue of transmission control, then the instruments...


other than what you swaid seem pretty good!

Answering Cons :
1. The Ford EGAS Sedan (AU Model) has the LPG Tank under the boot : and the spare bolts in the boot. It still uses room, but significantly less than in the past (enough that Im considering trying one on the EB)

2. Tank Installation : It is illegal to remove child points isnt it? - My Tank bolts only to the boot floor. If the brackets are made correctly this isnt a problem. Of course, when I had the XD it was way more dodgy

3. Gas Leak : There are far less explosions in LPG cars than petrol ones. If the tank splits, you might get a stream of gas and this will provide a flame, but the tank doesnt heat enough to explode. If you have that much LPG Leaking in your engine bay its the same as if you had petrol spilling around : Except you can smell the gas. Both can go boom.

4. AFL Failing : There are pressure relief valves on the tank so that if this does occur it will vent at the rear of the car (outside the boot).

5. Standard Tune : I am running the Standard EEC-IV, with LPG Injection. Back to Back, LPG is making more power. I also am able to fully utilise the red line and easilly : Something which isnt so easy in most LPG falcons unless they are boosted. Of course I also have that darn rev limiter because of it. Check out www.gas-injection.com. It works well, I get lean cruise, and have been known to get > 600km on highway cycle when I care. Of course, like a petrol car, I can get < 300 as well, but at the cost of LPG who cares.

6. Straight gas : Your right. Need to get to a gas station. However the range isnt so bad any more, and RACQ/NRMA covers that tow if it needs to. You wouldnt run your petrol car dry normally either though.

7. Your right here, which is why most Injected cars use Petrol to start and change over automatically. Gives the Fuel System a chance to run. I personally prefer to run straight-LPG Cars as Carrying 60kg of additional fuel makes less sense than stopping every 2-3hrs for a stretch. I can drive from the Gold coast down to Buladelah no sweat though on a single tank.

8. Gas conversions cost about $2k.... more for the newer injected ones. I save $50 a week at least at the moment, and most weeks closer to $75. That means that in a year I save $2500 which leaves me in front already. My Engine doesnt wear as much either.

Of course, Im pro-gas. Ive used it personally (not a taxi driver) for the past 15 years and have always had cars that drove much harder than most petrol ones. I took the time sometimes : On An earlier falcon (XD,XE) Getting the Distributor regrapphed (less than $100) takes care of most of the performance problems straight away, and as you said using the better flowing LPG Gear makes a difference. The EF and Later Falcons have a second Timing Map Built into the LPG versions of the ECU so that LPG is also more efficient. Unfortunately this also turns off the injectors so its of no use to me.

Cheers

Nigel

Hey Nigel, which gas-injection system are you actually running. I was under the impression that the Gas Injection Technologies setup was unavailable to the public. What I am most curious about is what power figures can be achieved before the injected gas setup petters-out?

Im one of GTIs test customers, and have been since I started. I love it, but cant give you figures on when it peters out.

Bill had his system on a HSV R8 - it delivered more power on the Dyno on LPG than petrol - and you guys might not believe it but economy comes right up as well.

At the moment he builds the injectors to suit the application. Hes also done a supercharged 6 EB.

look at www.gas-injection.com : It has the most info for now.

I was thinking that this applies more along the lines of the older Falcons, and cars in general. Having said that, I think the newer Falcons (at least from EA-ED (and I dont see why not in an EL) can be adapted to use the XE Falcon style mechanical dissy, and do away with the ECU all toghether.

Gab

from the ef up u can not do away with the ECU 'all thogether' as the ECU also control the whole dash, and transmission as well as spark and a few other things