Help - Converting AU Fairmont to GAS

[pgduncan]

Hi,
I'm very new this forum, I own a '98 AU Fairmont, its fuel consumption on the display shows 16L/100km. I cannot afford to pay this much, friends asked me to look into converting to GAS. Some said it can cause a LOT of problem and could cost you a fortune fixing them up.
Can someone pls tell me
1.if it is worth converting my car to GAS and
2.if yes I'm in Sydney any recommended place where I could go to to have this done.
3.Also is it best to do a full conversion or have both petrol and GAS

Any help on this would be greatly appreciated.

Many thanks for your help in advance.

Regards
PG

[Abacus]

Originally Posted by pgduncan

Hi,
I'm very new this forum, I own a '98 AU Fairmont, its fuel consumption on the display shows 16L/100km. I cannot afford to pay this much, friends asked me to look into converting to GAS. Some said it can cause a LOT of problem and could cost you a fortune fixing them up.
Can someone pls tell me
1.if it is worth converting my car to GAS and
2.if yes I'm in Sydney any recommended place where I could go to to have this done.
3.Also is it best to do a full conversion or have both petrol and GAS

Any help on this would be greatly appreciated.

Many thanks for your help in advance.

Regards
PG

You would get a better response if you posted this in the LPG Forum section of The Workshop.
http://www.fordforums.com.au/forumdisplay.php?f=71

But basically:

1. Yes it is worthwhile

2. Check the joint has been in business for a few years. A lot of fly by nighters have sprung up.

3. Dual conversion is fine. If you are doing long trips you can get caught in places where LPG is not available. If you run out of LPG anywhere, and you don't have dual fuel, you're kind of r**ted. The car won't run any better if it's not dual fuel and it's a lot easier to start on petrol.

I'd suggest an Impco mixer ring installation for your car. It will cost you 2/5ths of SFA after you get the $2,000 rebate and will pay for itself in a few months of driving.

[Uncle_Ken]

Originally Posted by Abacus

You would get a better response if you posted this in the LPG Forum section of The Workshop.
http://www.fordforums.com.au/forumdisplay.php?f=71

But basically:

1. Yes it is worthwhile

2. Check the joint has been in business for a few years. A lot of fly by nighters have sprung up.

3. Dual conversion is fine. If you are doing long trips you can get caught in places where LPG is not available. If you run out of LPG anywhere, and you don't have dual fuel, you're kind of r**ted. The car won't run any better if it's not dual fuel and it's a lot easier to start on petrol.

I'd suggest an Impco mixer ring installation for your car. It will cost you 2/5ths of SFA after you get the $2,000 rebate and will pay for itself in a few months of driving.

Good advice Abacus

I got mine from Med auto at Villawood (Sydney).

Don't know the latests cost (mine was a Airod premium kit for $2350:00 all up.)
That comes with the 65 lt tank, 1 year 20,000 k warranty.
Do you home work and you should be OK

UK

[GK]

Originally Posted by Uncle_Ken

Good advice Abacus

I got mine from Med auto at Villawood (Sydney).

Don't know the latests cost (mine was a Airod premium kit for $2350:00 all up.)
That comes with the 65 lt tank, 1 year 20,000 k warranty.
Do you home work and you should be OK

UK

I googled for a bit and found this. Interesting comparison between OMVL and IMPCO systems. Hope it helps.

Direct injection systems are likely to be 'nice' especially as the technology impoves, but I doubt they currently make enough difference to justify the cost (that's got to be re-evaluated monthly, as changes are afoot).

If I was in your shoes, and _if_ performance wasn't the number 1 priority, I'd go the omvl. Some don't like them, and they aren't 'magical' but they do have some advantages.

The first is that the impco setup uses a simple convertor and mixer
arrangement. This means there's moving parts and a diaphragm in both the
mixer (which is the lpg equivalent of a carb) and convertor. that's a second thing to wear out, to stretch, to cause inconsistencies, especially with age, and or any backfiring (though that's rare indeed on a ford inline 6).

THe omvl is a complex convertor. the bit that goes on the intake is an amos ring. Basically it's a venturi, no moving parts. It causes a signal (pressure drop, slight suction, if you will) when there's airflow across it. this then is routed to the convertor which delivers lpg appropriately. It will tend to have a slightly better idle (either will idle fine, it's not enough of a difference that 99% of motorists would notice or care) and better response just off idle than an impco _as long as_ it's properly installed and setup. That is important to note, as it's not always the case. Thankfully it's not all that hard to rectify.

On a related note, the way each system provides lpg for idle is different. On the omvl, a signal from the ecu or coil (on older setups) is fed to a tiny module, and when it's at a certain frequency, it bleeds in lpg - just enough for idle. If the car stalls, no coil signal, it cuts off the supply, so hard to flood it. On the impco, the mixer has the moving air valve (for want of a better word) that closes down with low flow, and it blocks off most of the intake, this then supplies a strong enough vacuum signal for idle supply. No running, no vac, so no lpg fed in there. But it can tend to bleed in after the car is shut off (or even cool and shrink back up the main supply hose to the convertor. In practice what this can mean is than the impco is occasionaly hard to start (even if the car starts on petrol as most efi setups do) or run
just after the efi switches over to lpg. the omvl seems better in this regard. Additionally if the omvl _is_ giving trouble, if you turn back to petrol, it will not supply under idle etc, so it will clear it's throat and run on petrol a bit easier. On the impco there's a slight chance it will draw in some remains of the lpg from the convertor and run rough for a second or two.

On either setup it'll end up with a feedback controller that takes a signal off the exhaust gas oxygen sensor and trim the lpg/air ratio for what will turn out to be decent fuel efficiency. So no big deal there.

To play devils advocate, I've had mostly good luck with omvl in tow car setups, but there are those who have seen problems with them. In particular their quality control isn't 100%, so you can sometimes have issues with them. I've also experienced a couple of failures of the plastic fittings that go into the omvls. They seem to fatigue with repeated heat cycling from exposure to underbonnet (and coolant flowing through them) temps. Not a fantastic thing to happen if you are in the middle of nowhere. But of course it's rare. I'm _almost_ of a mind to suggest that it wouldn't hurt to replace them every couple of years if you often travel far enough that having them fail would be a major inconvenience (it's generally not dangerous, since if the main supply
line to the engine intake breaks, it no longer sucks fuel and will cut out, and if the coolant line going into the convertor (it uses cooling system heat to vapourise the lpg from it's liquid stored state to a gas, which is why convertors are also referred to as vapourisers by some) breaks, the coolant drains (sure) but the convertor then freezes up with no supply of heated water and the car will cut out generally before the engine gets a chance to overheat from lack of coolant (nice little safety feature, that 'happened' sort of by accident by virtue of the design).

It's usually important to route the convetor 'the right way' and to quote Noddy 'there are many ways people mount them and if you ask enough
people all of them are wrong'. Which is partly true. Generally the main lpg supply line (the 1 inch thick hose) should go into the convertor and the converter be positioned so this hose is at the bottom (convertor up on its side, like a dish in the dishwasher, rather than laid out flat like a dish on a table when dinner is served). This is theoretically so that the contaminants in lpg (it has them) end up being brought through and burnt. Otherwise, if the hose is too high, they start to accumulate inside the convertor eventually to the point the sludge can totally screw up fuel metering.

Additionally it tends to help to have it so that the convertor is sideways (basically it's in the same position/orientation as the wheels on the car are, not turned 90 degrees like the steering wheel is). The reason being is that under hard braking, or acceleration, intertia will tend to then try to push the convertor diaphraghm one way or the other, affecting fuel metering (not a good thing with low rpms when you transition to full brakes, or are lurching forward and need to accelerate.


If you read the lpg related posts here (there's been a few recently) you'll note how much emphasis is put on going to a reputable fitter. The cheapest often turn out to be a poor choice, as they have to be doing something to make it worthwhile, generally cutting corners, or using less than stellar staff.

Very Interesting reading I thought!

I have both systems, both on AU Falcons and the system that I've had by far the least issues with is the IMPCO. I aggree with the dude's comments about OMVL having a little more on take off, but the IMPCO has simply been a "set and forget" system.

My best mate has an IMPCO on his AU wagon with no issues either.

I've actually replaced the OMVL recently and had the fuel stepper motor go also.

Both systems return around 12.8 - 14 litres per hundred on the highway and considerably less around town. I don't really measure anymore!

Hope that info helps.

All the best with your deliberations!

GK

[JC]

Some nice research there GK. I think I just found the cause of my "hard starting".

I also have the Impco, and it's not a bad system when the car is running - feels about the same as petrol power wise, and costs about half as much to fill up.

[sikford]

definatly was worth it once upon a time but as soon as gas reached a third of the price of petrol it is definatly not worth it, i couldn't justify the cost either and i work at a gas mob, one thing to look into seen as ya can get the government cash back thing is gas injection, not too long ago we put a BA Futura on gas injection and dyno'd it afterwards and it was making just over 140rwkw stock on gas.but atm i wouldn't bother as fuel prices aren't going to improve.

[Chamelion]

Monthly Savings $96
Payback Period 14 months
Annual Savings $1152
Weekly Savings $22

Based on: Annual Km:20000
Petrol Consumption 15L/100km
Cost of petrol/Litre:$1.29
Cost of LPG/Litre:$0.699
Conversion Cost $1300

On a $1300 out of pocket expense after government rebate, the above is what is calculated. How is it not worth it anymore?

[HenryV8]

Nevermind

[Abacus]

^^^^^

Beat me to it LOL.

I would also note that I suggested a mixer-ring setup over SVI for the original poster because of the age of the car and the longer pay-back period.

An SVI costs about $2,000 more than a mixer ring setup. The SVI system will produce marginal better fuel economy (maybe 5-10%) than a mixer-ring system, but as I, and others, in the LPG forums have demonstrated, that's about it. It would probably take the OP about 4-5 years to get the additional $2,000 install costs back.

SVI will give better driveability, less chance of backfires, and more power. Whether it is worth the extra $2,000 when it is being installed in a 10 year old car is questionable.

[HenryV8]

I made a mistake in my sums in post 8, and ran out of time before I could fix it.

This is what it should have said:

Assume:

Conversion Cost: $2,500
Rebate: $2,000
Cost after Rebate: $500

Annual Mileage: 20,000km
Petrol to travel 20,000km = 200 x 11 = 2,200L
LPG to travel 20,000km = 200 x 14 = 2,800L

Cost to travel 20,000km

Petrol: 2,200 x $1.379 = $3,034
LPG: 2,800 x $0.729 = $2,041

Annual Saving: $997

Savings over 3 years: $2,979

So, how is that not worth it?

[Edit]: Sorry Abacus, I was fixing this and didn't realise you had replied to my earlier post before i deleted it. I think you are correct about the mixer ring/SVI cost recovery. I would also put SVI in a newer car but not in a 10yo car that the owner might not hang on to for years and years. I go through about 25% more LPG than petrol with my SVI install versus an estimated 30% with a mixer ring, so I agree that there isn't much difference in consumption between the two.

[Abacus]

Yeah, I burn around 18% more LPG than petrol with my Parnell SVI install. It's more than I was told to expect when I had the install done but it's not bad compared to what others are experiencing. The average increase in consumption for SVI seems to be around 20-25% or so, against 30% for mixer rings.

The quoted figures of 5-10% additional consumption for SVI installs are just installer hype and general BS

As I have said before, If it was me, and I was putting the installation on a car I would keep for a while, I would still go SVI. For a 10 year old car I would go with a mixer, particularly if I wasn't too concerned about maximising power and just wanted the lowest cost of ownership.

[Mechan1k]

Originally Posted by Uncle_Ken

Good advice Abacus

I got mine from Med auto at Villawood (Sydney).

Don't know the latests cost (mine was a Airod premium kit for $2350:00 all up.)
That comes with the 65 lt tank, 1 year 20,000 k warranty.
Do you home work and you should be OK

UK

Ahhhh ... that's the same kit my mechanic installs ... hence why I wondered why it looked the same ... hee hee.

The Airod converter with Tartarini computer works a treat ... haven't seen one complaint from this setup yet.

[sednwol]

Around town with my wife's Fairmont Ghia the best I can get on gas is 16.5-17.5 Lts/100km, usually 19-20. DTE shows 450+ kms when I fill up but in reality if I get 300kms for 55 litres of gas I've down well. I loose a hell of a lot of savings on very poor economy compared to the gas. Very dissapointing! I am still saving money but poor economy is costing me savings. I have the car set on econ.

[Chamelion]

Sounds right for around town.

[GK]

Just filled the SR up tonight, got 13 litres per 100 with mostly highway kays, with a mix of city driving.

Not bad I thought.

Hmmmmm, I wonder how it will go with a 3.7 LSD? :

GK

[UU TS50]

looking into buying an AU S2 fairmont for my wife n got
a price of $3000 for gas conversion in WA we get $2000 state gov rebate
n $1000 fed gov rebate or vica versa so we will get all $ back

[pgduncan]

Very useful information, many thanks for your help here...

Best Regards
PG

[Chamelion]

Originally Posted by au302s3

looking into buying an AU S2 fairmont for my wife n got
a price of $3000 for gas conversion in WA we get $2000 state gov rebate
n $1000 fed gov rebate or vica versa so we will get all $ back

Wish they did that here in QLD :(

[Mechan1k]

Originally Posted by GK

Just filled the SR up tonight, got 13 litres per 100 with mostly highway kays, with a mix of city driving.

Not bad I thought.

Hmmmmm, I wonder how it will go with a 3.7 LSD? :

GK

If just driving around town ... I reckon going 3.7s will be better for economy.
Although I have heard that going 3.7-3.9s isn't too detrimental for economy. With the shorter gearing (especially for LPG vehicles) it will take less effort to get off the line compared to what it is like now.

I am so tempted to go 3.7s in the work ute ... it'll be much more driveable than what it is now ... plus i don't get to see the freeways that often in it.

[GK]

Originally Posted by Mechan1k

If just driving around town ... I reckon going 3.7s will be better for economy.
Although I have heard that going 3.7-3.9s isn't too detrimental for economy. With the shorter gearing (especially for LPG vehicles) it will take less effort to get off the line compared to what it is like now.

I am so tempted to go 3.7s in the work ute ... it'll be much more driveable than what it is now ... plus i don't get to see the freeways that often in it.

I've just booked the car in for Friday. Going from 3.08 to 3:7, single spinner to LSD, all new bits, plus the 2 rear wheel bearings will be done also. God willing, that will eradicate me of all my vibrations, and certainly junk that awful 3.08 ratio and give me some kick in the pants feeling.

The price, don't even ask, much more than I expected or wanted to pay, but hey, I've got the car on gas, manually converted, so I'm in for a penny, in for a pound now!

GK

[Mechan1k]

Good call on replacing the wheel bearings ... may as well ... it's all going to be apart.
I'd do the same as well if I was going to get the diff done.

I have been quoted around the $1,250-$1,500 mark for a diff replacement ... bearings will add to that with the extra labour as well.

If you are going to keep the vehicle for a long time ... it's worth it ... and that's how i see it. I just wish I had the cash at the moment for a diff swap ... but not for a while by the looks of things ... so i will have to stick with the 3.23's for now.

[mik]

there is also another cost for lpg, ignition parts are prone to need replacement more often compared to petrol (lpg needs good spark) as mentioned a good fitter is worth there weight in gold ,my mate had a what initially seemed like a good system, but 12 months down the track it turned into an ongoing nightmare.
And speaking of wheel bearings GK, recently my rear irs wheel bearing /s started becoming noisey so i rang Ford spares $26.30 for a hub nut and $168.00 for the bearing(one side only) Action bearings will do the bearing for $80.00 if anyone is interested, i dont know that the after market bearing is as good qaulity as original but less than 1/2 price so i will give it a go.

[GK]

Originally Posted by Mechan1k

Good call on replacing the wheel bearings ... may as well ... it's all going to be apart.
I'd do the same as well if I was going to get the diff done.

I have been quoted around the $1,250-$1,500 mark for a diff replacement ... bearings will add to that with the extra labour as well.

If you are going to keep the vehicle for a long time ... it's worth it ... and that's how i see it. I just wish I had the cash at the moment for a diff swap ... but not for a while by the looks of things ... so i will have to stick with the 3.23's for now.

Tell me more about this price you've been quoted and for what bits in particular? I'm keen to compare prices.

GK

[sly]

Originally Posted by Mechan1k

I have been quoted around the $1,250-$1,500 mark for a diff replacement ... bearings will add to that with the extra labour as well.

A couple of years ago I was quoted $650 IIRC for a brand new 3.73 open centre, LSD extra, I didn't ask how much extra as I just wanted a "drive in, drive out price".

Total parts & labour quote was approx $1800 for 3.73 LSD fitted. I didn't have the cash at the time so didn't go ahead. The diff is starting to get a bit noisy after 330,000km, so I might revisit this. ATM I can't find anyone locally who's interested enough in my force-feeding project to return phone calls :

[sly]

Today's price in Newcastle is $2200 DIDO.

$470 for LSD, $700-odd for 3.73 centre (both supposedly brand new) plus new bearings (mandatory, I'm told) and labour. Does not include any sort of speedo adjustment. I can get the speedo recalibrated elsewhere for $440, will leave for now as I believe it's a simple adjustment via the edit.

Getting the job done Monday.

Apologies for hijacking the thread BTW, maybe we should take this line of discussion elsewhere LOL.

Anyway back on topic, I have a 99 Forte with mixer-ring Sprintgas system and have just had a Sprintgas Dream XXI-N SVI system put on the 02 Futura (for optimisation of future forced induction). The SVI system's early figures show 12.96l/100km country/highway and 15.5 or so around Newcastle suburbs (still a bit more free-flowing than Sydney) compared to the mixer system's last fills of 14.22 and mid/high 16's respectively.

The SVI drives nicely on an otherwise unmodified car, is pretty much on par with the mixer on a car with Pacemaker 4499's, 3" metal cat, 2.5" 2-muffler system, K&N panel filter, enlarged intake, vernier cam gear (2 deg advance) and 98-octane edit.

The mixer type system will do the job and save you money, the SVI system will do a better job but cost more up front. Up to you to decide which is for you.