I just bought a Duel Fuel TH Magna Advance 3.5 Auto.

This is my first duel fuel car and am enjoying the savings with Gas.

What kind of mileage are you guys getting out of a tank?
My worst is 420 and my best so far is 480 and i doubt whether i will get much more even pussy footing around. Even on a country trip, mileage isnt a lot better than city. I converted it back to L/100 and im getting between 12.9./100 and 15/100.

We normally get over 600 km from a tank full of LPG (65L). At times, we get up to 640, but mostly nearer 600. Ours is a 3L, manual tranmsission. Mostly straight (although hilly) country running. If my wife does a lot of short trips, we get much less - down to 540 km from a tank. I am disappointed about this economy, even though it is good compared to others, because I expected that it should comfortably give less than 10L/100km, but that is what it always has done.

Ive got a 3L Auto TF advance on LPG.

Just changed the O2 sensor in it, Now its averaging 12.7L/100km through the city. Thats not driving it hard or easy. Just normal...

Please specify if you are talking about Litres of lpg or petrol equivalent, or just put it in $/100kms, gets confusing

We normally get over 600 km from a tank full of LPG (65L). At times, we get up to 640, but mostly nearer 600. Ours is a 3L, manual tranmsission. Mostly straight (although hilly) country running. If my wife does a lot of short trips, we get much less - down to 540 km from a tank. I am disappointed about this economy, even though it is good compared to others, because I expected that it should comfortably give less than 10L/100km, but that is what it always has done.

This is excellent economy.. Whats the issue...People would kill for that ecomony on Gas... Maybe 1 in 10 or 20 ppl would get that... Be happy....

I get 12 lp100 on the daily routine work/kids... I used to average 420 a tank, I saw another installer, and I'm around 500-550.. I reckon I'd see 700km per tank on a trip (like to MM)....

Please specify if you are talking about Litres of lpg or petrol equivalent, or just put it in $/100kms, gets confusing

$/100km isnt a good measure. Neither is saying I get 450km's to a tank.

Firstly, $ or cents per litre isnt standard around this country - In SA we are paying 75.9cpl where as in Vic I think its only 65cpl

Also, specifying how many km's one gets to a tank isnt much good either as tank size can differ... Could be a donut LPG tank or a one in the boot like SH00T's and myself's.

Litres per 100km OR Kilometres per Litre is the only way we can accurately compare economy.

I have a 60 ltr donut tank so my max fill is about 53 ltr.

I expect my O2 sensor is shot as I get between 280 and 320 around town these days, I haven't done a country trip for ages but the best I got was 600kms years ago.

I had my TJ auto converted to a SGI system in 2007 - one of the best things I have ever done in my life. City driving I get around 12-13lt/100km, country - I get around 10-11lt/100km. Never spent a penny on the gas system except changing filters every year and get the computer checked in every 2 yrs. When had it converted the reading on odometer was 65,000km, now 152,000km. It used to cost around 25$ on average for a complete fill, now close to $40 :( (max capacity 60 litre, but I never could fill in more than 47 lt). I can't think of owning a car without having it converted to LPG.

I honestly don't know how anyone can get such good consumption. It's just impossible. At first I had a mixer system installed. Consistent city driving would get me 15.5 per 100. Iater upgraded to svi system, best I get around the city is 14 that was with manual and before my supercharger. Consistent rule is you consume 30% more on gas because of lower colorific value. How can you get 12 around the city??? That means on fuel you should get around 9 I call bullshit on that

" Quote Originally Posted by erad View Post
We normally get over 600 km from a tank full of LPG (65L). At times, we get up to 640, but mostly nearer 600. Ours is a 3L, manual tranmsission. Mostly straight (although hilly) country running. If my wife does a lot of short trips, we get much less - down to 540 km from a tank. I am disappointed about this economy, even though it is good compared to others, because I expected that it should comfortably give less than 10L/100km, but that is what it always has done.
This is excellent economy.. Whats the issue...People would kill for that ecomony on Gas... Maybe 1 in 10 or 20 ppl would get that... Be happy....

I get 12 lp100 on the daily routine work/kids... I used to average 420 a tank, I saw another installer, and I'm around 500-550.. I reckon I'd see 700km per tank on a trip (like to MM).... "

I would love to get 700 km from a tank of gas. The best I have had has been 660 km, but thta was a one-off.

Most of our running is in open (but hilly) country. It is at the speed limit (mostly 100 km/H). We were getting down to 500 km from a tank, and I replaced the Oxygen sensor (no change), the spark plugs (no change) the high tension leads (it got worse - they were Bosch leads), the gas converter (still no change) and then a new set of HT leads with a set of NGK Iridium spark plugs (WHOOPIE!). We had backfires and poor power up to that point, but now it is very smooth and quite powerful. I still would like better economy.

My NL Pajero runs at what I would call a sweet spot. It uses a lot more gas (about19 L/100 around town and 16 L/100 on an open run not towing our caravan). However, its performance is outstanding and when you consider the aeordynamics and weight of the vehicle, I am more than happy with its consumption. It has the NGK Iridium plugs and NGK leads. In both cars, I didn't say anything to my wife about what I had done when I fitted the plugs. Her first comment in both cases was "What have you done to the car? - it really runs a lot better". I don't thing the plugs greatly iproved fuel consumption, but they certainly improve low end pickup.

With my auto 2.6L TS I usually get about 17L/100kms without any air-con, all short trips, max 70kph.
I once got down as low as 10L/100kms but that was a very long trip on highways and country roads.

I honestly don't know how anyone can get such good consumption. It's just impossible. At first I had a mixer system installed. Consistent city driving would get me 15.5 per 100. Iater upgraded to svi system, best I get around the city is 14 that was with manual and before my supercharger. Consistent rule is you consume 30% more on gas because of lower colorific value. How can you get 12 around the city??? That means on fuel you should get around 9 I call bullshit on that

I agree with this. 10L/100km from SVI (not liquid injected lpg) system would be very conservative, and just about impossible from a mixer, unless erad has the most lean & efficient mixer lpg system known to man and/or the driver doesn't use the accelerator at all.

I've got a 3.5L manual Tj using a mixer lpg system and driving mostly in the city, with heavier foot I'm averaging around 16L/100km. If I take it real easy and avoid the traffic, it drops to around 14L/100km at best.
On the highway the best I've gotten is 12.5L/100km.

(I use L/100km as it's the only real accurate way to compare lpg economy. Tanks differ in size and also the weather can dictate how much %wise the tank can take - i.e. you can fill more lpg on a cold day than a hot one).

My system is a closed type system controlled off a seperate computer and it generally runs quite lean. I've fitted IridiumIX plugs and use NGK leads. No backfires as such and plenty of performance. I estimate I still get around 105-110kw at the wheels on lpg. Will find in a few weeks when the car will be put on a dyno.

Being a mixer system, I still need to run petrol, and I follow a 4:1 ratio of 4 tanks of lpg to 1 tank of petrol. So overall, cost per 100km is around $11. Not too bad considering a same year toyota corolla would cost about the same at current fuel prices (~$1.45)

I have only gotten into the habit of saying figures in L/100km petrol cost equivalent because I am not usually talking to people with LPG systems, I can't be bothered explaining it to them.

I once had someone say to me when I complained that the price of LPG went from 55c to 90c basically overnight:
"I don't know what you're complaining about, I had to pay $1.40/L for petrol to fill my car up today"

Took him an annoyingly long time to understand that it uses more litres of fuel than it would on petrol... and even longer to expain that it was the equivalent to the petrol price jumping to $2.10/L tomorrow.

People don't often understand that for sure. I always clarify how much the car costs per 100km as well because I still need to run petrol and of course you use more lpg.

I hear so many people say things like "ooo get lpg, it'll more than halve your fuel costs!" and I get a bit annoyed :nuts: :bash:
Cost of Lpg per litre is, yes, half the cost of petrol, but the fact it uses more per cycle compared to petrol, requires extra maintenance (better spark plugs, better leads plus regular servicing) and still requires petrol means that lpg reduces the cost, but in no way, in most cases, halves one's fuel costs.

This still doesn't consider the actual cost of the conversion, less the current measley $1000 government grant.

My car doesn't use special spark plugs or better leads, do you think I could get better economy if it did?

Just depends. How is the current performance with lpg? Backfiring? Rough idle? Hard start?

I'd doubt you'd save many litres of lpg per 100km, but I'd surprised if you didn't have a decrease. That is, assuming that performance isn't too great for you right now.

"If it ain't broke, don't fix it?" Upgrading the leads & plugs is a good idea, but there are no guarantees.

That being said, 18L/100km for a 4 banger seems a little bit high. However I don't know how the Astron's generally perform on lpg to make that judgement. With the 6Gxx it seems around 14-15L/100km on lpg is on average.

Magna PI, you need to drive my car around for a while, same leads, one gas service in 70,000...

Old systems use more, sure, modern systems not at all.....

I laughed when I saw the lpg falcon average of 15.
I'm in the 11's at the moment...

Just depends. How is the current performance with lpg? Backfiring? Rough idle? Hard start? .

No none of that, starts easy, never backfired, runs smooth, idle seems fine (sitting at lights in gear shakes like hell but that's a whole different issue)


That being said, 18L/100km for a 4 banger seems a little bit high.

Yeah I know, its never taken to lpg like the V6s seem to, but I've always thought the problem comes down to the engine having far too much displacement for a 4 cylinder. The thing was never a '4cyl' in terms of economy in the 1st place.


The best car on lpg (when I say lpg I always mean dual-fuel) I have ever encountered was my sisters 2.4L 2002 camry, ran like a dream, almost no noticeable loss of power, and the price $/100kms was easily less than what they were bragging for the prius.

I've just bought a new O2 sensor so ill see if that improves economy. But so far new iridium plugs, filters and oil change and the motor is running sweat.

On average im doing $9/100k

im currently reevaluating my lpg consumption (due to repairing the regulator, and re-calibrating the system).
my trip computer always hovers around 315km@38km/h to a tank this usually equates to 46.5l of lpg and 15km of petrol running.
so 46.5/3(00) = 15.5L/100 (when trip computer says 12.5 so thats +25%)
15.5l @ 80c/l = $12.4/100 (based on last lpg price)

the car has done 160k so its probably due for an 02 sensor, and the iridium plugs are almost 100k old, not to mention i also use mobil1 5w50 where i could use their 5w30 or even 0w40 (both of which are better for fuel economy)

we'll see what transpires after the next tank or so

MAgnaPI quoted "I agree with this. 10L/100km from SVI (not liquid injected lpg) system would be very conservative, and just about impossible from a mixer, unless erad has the most lean & efficient mixer lpg system known to man and/or the driver doesn't use the accelerator at all."

Most of our running is at highway speed on cruise control and we normally get arond 600 km from 65L of gas. I have kept records of everything put into each vehicle and can assure you that teh records are correct over a long period. Both our vehicles now have over 240000 km on them and they both are very good on economy and peformance. Both are mixer systems. Both have been carefully maintained, although gas services have been nil - what can a gas check do other than set the idle mixtures? The modern mixers controlled by stepper motors using the oxygen sensors are pretty good if they are set up properly in the first place

my TW wagon on LPG, Impco mixer system, gets about 18l/100k, around town, driven not very hard. I've taken it to 3 places to have everything checked, and they all say everything is fine. It might get 13-14 in the country.

Hi all, I own a factory fitted dedicated LPG TL. It does 11.6l/100km average. In worst driving with air-con on constant, it returns 12.5l/100km. See if this helps.

That sounds better, must be a good install, combined with good driving...
TL person, on a long trip, it seems the 10 l per 100 should be achievable...

I'm sick and tired of blokes that reckon they are the best LPG installers/service technicians in the country, but clearly aren't....
10 l per 100 from a mixer is acheivable... My uncles advance gets it, my old (60y.o.) friend, an old installer gets it...Mind you, that would filling up on the start of long trip, doing 400 k's on the highway, and filling/topping up with 40 litres...

If any one has a mixer in Qld with poor ecoming/running rough, i'll chase up the bloke who last serviced my uncles TJ Advance, he is Good....

That sounds better, must be a good install, combined with good driving...
TL person, on a long trip, it seems the 10 l per 100 should be achievable...

I'm sick and tired of blokes that reckon they are the best LPG installers/service technicians in the country, but clearly aren't....
10 l per 100 from a mixer is acheivable... My uncles advance gets it, my old (60y.o.) friend, an old installer gets it...Mind you, that would filling up on the start of long trip, doing 400 k's on the highway, and filling/topping up with 40 litres...

If any one has a mixer in Qld with poor ecoming/running rough, i'll chase up the bloke who last serviced my uncles TJ Advance, he is Good....

Agree with what SH00T is saying. When my system was installed on my car, the fitter (a client of my dad) took a week to install it. This was mainly due to sourcing the correct parts needed to make it run perfect with no difference between LPG and petrol, but he also took his time so I wouldn't have to come back because I was unhappy with it.

He also highlighted that the car needed a few things repaired inorder to achieve the best performance out of my system. Plugs and leads as my old setup were very old.

Now because it runs perfectly on LPG, I hardly ever run it on petrol, I would do a tank over 6months. I know SH00T is the same.

Fitting LPG is one of the best mods I have done to my car as of yet.

The only way you can get close 10/100 from LPG, to this is on a perfectly flat highway, but whats the use quoting highway figures, they are very misleading as even old commodore will produce decent consumption of a flat highway run. There is absolutely no way you will get this in the city where most people drive their cars

Look at new FG falcon with state of the art liquid injection LPG system get 12.6 average combined, and that is manufacturers claim which are always hard to achieve, and yet some people here claim they can match that with their magical outdated mixer system on 15 year old engines.. While yes magnas are lighter but falcon has 6 speed gear box which will be impossible to beat for efficiency.

Im all for LPG, i ve been running it for years, its a far better fuel that petrol but i will never believe such ridiculous claims

Hey, when manufacturers quote fuel economy, is that generally with or without air con running? (I would assume without of course)

That sounds better, must be a good install, combined with good driving...
TL person, on a long trip, it seems the 10 l per 100 should be achievable...

I'm sick and tired of blokes that reckon they are the best LPG installers/service technicians in the country, but clearly aren't....
10 l per 100 from a mixer is acheivable... My uncles advance gets it, my old (60y.o.) friend, an old installer gets it...Mind you, that would filling up on the start of long trip, doing 400 k's on the highway, and filling/topping up with 40 litres...

If any one has a mixer in Qld with poor ecoming/running rough, i'll chase up the bloke who last serviced my uncles TJ Advance, he is Good....


Totally agree with you dude. Mine is a combine figure and I am easy on "gas". Mine is a car produced by Mitsubishi and Impco. It is a dedicated unit with proper calibrated CPU and no petrol tank. It is a real show case when I fill up when other people came around and look at my car's fuel filler and found only a LPG inlet. Mitsubishi makes cool things but no one noticed and no advertisement! What a shame.

Hey, when manufacturers quote fuel economy, is that generally with or without air con running? (I would assume without of course)

No air con. Sorry to say. Unless one of those pointless Hybrid that can not turn air con off due to too many buttons to press or silly turn off sequences.

I'm with Andrei on this. 10L/100km would have to be an absolutely perfect run on the highway and not something I'd use to give people an indication of the expected economy of lpg. When a car runs at the same speed & rpm for miles on end then the engine is barely working and uses very little fuel. The LPG system that the FG runs is a liquid injected system and is the best system currently available, and even that is around the same economy figure as petrol, which is actually quite impressive considering the characteristics of lpg compared to petrol.

I have plenty of friends with mixer lpg systems, and my dad has also been running his car's on lpg since the late 80's. In each case, there's always, at least, a good 20-30% jump on economy when using a mixer system.

My car runs great on lpg and has one of the best mixer systems you can get. It is a properly setup as a 'closed loop' lpg system that uses a separate little ecu to control the mixture of air & fuel and allows my car to start on petrol and then switch over to lpg.
The average city lpg economy for me is around 15L/100km, and my petrol is around 12L/100km.

My gas is at 18.4litres per hundred in the city and I don't know why.. :( Going to try and replace the coil/dizzy and see how that goes.

Save making a new thread, and since LPG people are already here, I will ask this here:

I have recently been having a problem with my LPG system, in particular, it seems to be the change-over switch and gauge.
Does anyone else have one of these: http://www.apexus.com.au/images/gauges/pg200-a.gif
Or know anything about them?

What it has been doing is sometimes dying suddenly while driving on lpg and only working again when I switch back to petrol.
Then, it wont switch back to gas (listening for the solenoid valve click) unless I pull it out and fiddle with the switch, seems like something is loose.

Thing is, when I pull it out to fix it, the back of the switch is very hot, but I don't know if it has always gotten hot, or if it is a symptom (or a cause?)

Anyone encountered an issue like this?

Just you before you guys start replacing all different bits pieces, I had a chat to installer mate of mine, who used to install vapour ring systems, and also read a recent thread in here about a vapour that was large it restricted airflow ( so the OP beleived).
He said the ring size had a large amount to do with gas delivery. I wouldnt mind seeing a few pics of the ring in the intake ( if possible, to see if there is such a variance) and if you are concerned, you could check with the manufacturer, which ring is the correct ring for you car....
May help, may not, but his advice to me has been bang on before...

Have had both veradas on impco gas, non injected that is. Always between 13-14 litres per 100 klms. I keep full records on mine, so this is spot on. Wouldn't believe how much you save.

We cover a lot of distance with both our vehicles, and since we are on a self funded pension, running costs are critical to us. I did the sums years ago, and found that I needed to do about 20000 km to recover the cost of converting each vehicle to gas. Since then, every 20000 has returned us the installation cost over and over again. That is worth a lot of money. Since then, LPG costs have rocketed (so has petrol, but not by the same percentage) and the distance to revocer the conversion cost may vary, but it will still probably be less than 30000 km. It all depends on where you live and where you drive.

Yes, there are disadvanatages to running gas, but overall, as far as we are concerned, there is no cheaper alternative. Even diesels in my 4WD Pajero would not be as cheap as LPG.

Just done another tank, 13.5L/100 or $9.50/100 at 69.9c per litre which is the highest ive paid

My heart bleeds for you - 69.7 cents per litre! I live in Cooma NSW - and 69.7 is the price in Canberra - 120 km up the road. They are charging 99.9 cents per litre here. Dammit - it wasn't that much dearer across the Nularbor recently. Petrol is dearer too, but not be that much of a difference. It must be the cartage to get it to here from whereever - the local dealer wouldn't be overchargiung us - surely! Grrrr

It must be the cartage to get it to here from whereever - the local dealer wouldn't be overchargiung us - surely! Grrrr

At least there is some excuse that far west, in queensland at the start of this year it was up to 95c/L just about everywhere, and it went up to that from 55c/L basically overnight.
We were told it was because of a cold winter in europe, despite it not being that expensive in the southern states.

At least there is some excuse that far west, in queensland at the start of this year it was up to 95c/L just about everywhere, and it went up to that from 55c/L basically overnight.
We were told it was because of a cold winter in europe, despite it not being that expensive in the southern states.

i was reading somewhere (cant for the life of it remember where) but currently our gas prices should be 20c/L lower.... i guess any excuse will do though

In WA, apart from the local areas around Perth, LPG prices have been extortionately high for years. I never could understand that because the stuff is brought ashore and processed at Karratha and piped down to Perth.

My last fill got me 316kms out of 46 litres of LPG with the A/C on for about 1/3rd of that time, that was about $10 per 100kms.

In WA, apart from the local areas around Perth, LPG prices have been extortionately high for years. I never could understand that because the stuff is brought ashore and processed at Karratha and piped down to Perth.

most of the automotive lpg is processed 40km south of perth at the BP refinery in kwinana, when it broke down a few months ago gas prices jumped significantly

Well went on a highway fishing trip sitting on 110-115 with 5 people and a fishing gear in the boot. Achieved 520ks on the gas before she died so this is the best so far. It took 63 litres to fill so average consumption is 12.1l/100.
On average im getting around 420-440 a tank in day to day city driving so this is around 15.0l/100.

Qld prices have been shit around me for a while, but i keep running lpg with a small reserve of petrol cos I like having a reserve tank for peace of mind.

Can it cause problems if you run lpg until it is so empty the engine loses power on acceleration? Would this lean it out too much?

Or is it unlikely to do damage in a NA low rev 4cylinder engine compared to a turbo car running out of fuel under load?

Qld prices have been shit around me for a while, but i keep running lpg with a small reserve of petrol cos I like having a reserve tank for peace of mind.

Can it cause problems if you run lpg until it is so empty the engine loses power on acceleration? Would this lean it out too much?

Or is it unlikely to do damage in a NA low rev 4cylinder engine compared to a turbo car running out of fuel under load?

When it is likely your under full load and its starving for fuel?? I always run my gas to empty and switch to petrol and look for a petrol station.

What prices you paying in QLD, in Melb im seeing 63.9 on a regular basis

Running a tank to totally empty has its risks. You can get condensate form in the bottom of the tank, and this can be sucked through into the converter and block it up. If you only go to empty once in a blue moon, you may get a large gutful of sludge into your converter. If you regularly go to empty,it is more likely that there won't be much sludge and the little bit you suck through won't block anything. I used to regularly go to empty, and when I pulled the tank on each car for the 10 year retest, there was nothing in the tanks at all. Cannot say wheteher this was because there was no sludge in the first place, or if I cleaned it out on a regular basis

When it is likely your under full load and its starving for fuel?? I always run my gas to empty and switch to petrol and look for a petrol station.

What prices you paying in QLD, in Melb im seeing 63.9 on a regular basis

1. Wasnt saying that I was driving it under full load and it was starving, was saying that I had heard running out of fuel in some other cars can lean it out, but for my car its rarely under full load.

2. its only just gotten down to 65c/L this week after being up over 75c/L (often 85+) for most of the year.