Subaru Outback 2005 Conversion

[Hloni]

I did a lovely 1300km round trip over the Christmas break with the family. 200km were 100% petrol as I didn't feel like refilling in the rain when the onboard tank ran dry. I can genuinely say I've enjoyed the ability to do "self refueling", because we don't have Autogas really at fuel stations.

Scale comes in handy to check the LPG has been fully dispensed out of the bottle.

IMG-20221228-WA0016.jpg (185.16 KiB) Viewed 6768 times

How does one calculate, alas estimate, the carbon footprint of LPG vs Petrol? It'd be great to say to friends at the barbie next month, "my carbon footprint is x% lower running autogas vs running on 95 octane".

[Gilbertd]

No idea how you would calculate it but for their low emission zone vignettes the French class a car on LPG or CNG as emitting the same levels of pollution as a hybrid. Although Propane is produced from the same stuff they refine into petrol, it is actually a waste product. It is the waste Propane that you see being burned off at the tall towers at a petrol refinery, so you are reducing the amount of global warming by using something that would otherwise just be burned off.

What pump are you using to refill from the bottles? That could be an option for other people living in areas that aren't well served by filling stations. In fact, it would have been useful for me last year. I drove to Sweden and had to do most of the journey on petrol (which, in Sweden at the time, was probably the most expensive in the world!). The mylpg.eu website shows 78 filling stations in the whole of Sweden but only a couple of them are on filling station forecourts, the rest are at depots where people go to get the bottles refilled. Problems with them are that they are only open 10:00-17:00, are hidden away in industrial areas and I was driving through the night so they were all shut anyway. A 47kg bottle in the boot would probably have given me enough range to not have to use any petrol.

[LPGC]

We are all very interested in your pump @Hloni, please see if you can find something out about it and/or take pictures of it for us!

I'm not a chemist but I expect it'll boil down to something along these lines - Petrol is C8H18 while LPG is C3H8, I take it that means petrol has a ratio of 18 hydrogen atoms to 8 carbon atoms while LPG has a ratio of 8 hydrogen atoms to 3 carbon atoms.... 18/8 is 2.25 times more hydrogen than carbon, 8 / 3 is 2.67 times more hydrogen than carbon, so maybe we can do 2.67/2.25 and find LPG is made up of 18.5% more hydrogen (18% less carbon) than petrol? Burning carbon produces CO2 (and CO), burning hydrogen produces H2O which is water. If I'm correct so far I'd still expect it to be necessary to include other factors such as the higher calorific value of LPG (46>51MJ/kg) compared to petrol (44>46MJ/kg) by weight makes LPG look even better but offset because to burn that Kg of LPG we need more air (LPG stochiometric ratio 15.4:1 versus petrol's 14.7:1). If I were to try to include those factors I'd go with the middle value for petrol (45MJ/kg) versus LPG (48.5MJ/kg), which makes a 7.8% positive difference, then include the stochiometric data so 15.4/14.7 which makes a 4.8% negative difference. So with all my considerations done I might expect running on LPG to make a difference of 18% lower CO2 emissions not accounting for calorific value or stochiometric ratio, then including calorific value and stochiometric ratio a difference (lower CO2) of around 20%. I would welcome correction or better explanation from a chemist! Far from certain I got any of this correct or put the operators in the correct positions, also aware I didn't include wet/dry heating values (if we burn a fuel that produces water some of the heat goes into heating the water that has been produced and water/steam takes more energy to heat than air or CO2)

[Hloni]

I'll try find specs of the pump. The one I have literally was an "unbranded barrel", and I suspect the supplier removed the branding because they've seen my interest in finding a long-term solution.

I will try get some specs from him. Let me see what I can get from him.

[Gilbertd]

Don't forget that petrol isn't just a pure Hydrocarbon, it has all the other additives in it which, when burned, are what cause the bulk of the noxious compounds in the exhaust. I was once told that the additive put in as a lead substitute to lubricate valve seats is the sticky stuff from Sellotape! Propane is, or at least should be, just the Hydrocarbon gas without any additives. The only thing added to it is a tiny quantity of a lubricant to stop the pumps seizing up and it is that lubricant that you will find as the 'heavy ends' in your liquid phase filter. The Autogas sold in some European countries is a mix, anything from 90/10 up to 50/50 Propane/Butane, so what you are buying in bottles may be a mix too.

[Brian_H]

Its a bit open to interpretation if you look around

One example
https://www.drivelpg.co.uk/about-autoga ... -benefits/
Bits of note there
"At the Tailpipe
LPG cars have 11% CO2 benefit
Well to Wheel – the figure calculated for LPG is considerably lower than other fuels:
Diesel is 29.2% higher than LPG
Petrol is 26.8% higher than LPG.
Extensive independent tests showed that:
One diesel vehicle emits 120 times the amount of fine particles as the equivalent LPG vehicle.
It takes 20 LPG vehicles to emit the same amount of NOx as one diesel vehicle."

Figures elsewhere indicate around 40% difference. As said above, there is no Benzene etc in autogas unlike unleaded petrol so its not just the carbon footprint that you could consider reduced.

[Hloni]

... Propane is, or at least should be, just the Hydrocarbon gas without any additives. The only thing added to it is a tiny quantity of a lubricant to stop the pumps seizing up and it is that lubricant that you will find as the 'heavy ends' in your liquid phase filter. The Autogas sold in some European countries is a mix, anything from 90/10 up to 50/50 Propane/Butane, so what you are buying in bottles may be a mix too.

Is it then safe to assume that one need to consider a lubricant of sorts when refilling with "cooking gas" as this would lack the lubricant/additive which may have been considered for autogas? If yes, what may that lubricant be?
The car starts on petrol, so it's most likely as that lubrication to the petrol tank.

[Brian_H]

Cooking gas cylinders would still be filled using a pump or compressor at the depot so shouldn't be an issue. Given you have to invert the cylinder you should be getting anything like that going through with the gas

[LPGC]

I had contaminants / impurities / additives in petrol in mind when I wrote post #23 but I was approaching it as a CO2 emissions question. For sure LPG is purer than petrol and doesn't contain anything like as much sulphur etc... But we could put CNG/LPG at the top of the list of cleanest fossil fuels for vehicles, then there'd be quite a gap between those and petrol, but then there'd be a massive gap between petrol and diesel with all of diesel's particulate emissions etc and NOx emissions an order or magnitude or so above NOx emissions of LPG or petrol. These days it seems to be all about CO2, if those other emissions were considered anything like as important as CO2 by the powers that be then it'd be surprising that diesel wasn't made illegal years ago.

@Hloni Can we clarify that you pump gas out of cylinders into your vehicle tank... It isn't just a case of you running the car directly from inverted gas bottles - You are able to put a gas bottle near/inside the car, pump gas from those bottles into your vehicle tank and not have to carry those bottles around with you to take advantage of the gas that they contain(ed)?

[Brian_H]

Looking at the post on Dec 7th he does mention a pump, and he clearly can't be driving it around with that hose connected?

I do find it a bit surprising that jubilee clips hold that hose in place though.

[Hloni]

Whilst waiting to give a spec of my pump (awaiting the details), I've looked into these pumps http://lpgpumps.in/#. Will be trying out their 12v as I wanna convert another vehicle fory dad, and where he lives there isn't an autogas station, however cooking gas is plenty.

Alibaba sells them for USD300. A little overpriced, however thus far they seem like the only real option I have which I can confirm the specs of.

[LPGC]

Thanks, the pumps on that website seem to use piping that looks a bit dubious for use at some of the potential pressures involved?

[Gilbertd]

That polyethylene braided tubing is rated at 10 bar maximum pressure so I would suspect it is on the limit at best. I'd want to use something rated at least twice that.

[Hloni]

Yeah, one would need to upgrade that hose before even transfering the 1st liter.

I've though also found a potential lead. https://www.adecomotive.com/en/electric-pump-for-lpg

[Hloni]

Over the last few weeks, it's become very clear that LPG is potentially one of the future alternatives for ICE owners and drivers. The uptake and appetite though seems very low by many, and watching on the UK based LPG Cars Facebook group, a considerable number of filling stations are removing autogas from their courtyards.

In South Africa we really have a limited number of companies that do conversions. Pricing varies so much, to such an extend that some charge double of what the other does. The refueling network is close to non-existent if we are to be honest, however, self refueling may be a lifesaver.

I'm highly considering trying my 1st conversion on a 4 cylinder, something like a 10 year old Ford Fiesta or Toyota Yaris or VW Polo. I see that LPG ECUs come in MP32 as well as MP48. What are the fundamental differences between the 2, why would one go with one over the other?
From a few videos I've seen online, installation is pretty straight forward if one works meticulously. The calibration and accessing the ECU is what I'm still trying to get my head around as it's unclear if there are different configuration software for different manufacturer ECU, and if so, how many various ones are out there. Take for example AliExpress, they have a kit like this https://a.aliexpress.com/_EzVRRgx, like, what software would something like this use which most likely is generic?

Kits don't seem badly priced. Freight and import taxes may be the inhibitor, however I'm keen to get in my 1st kit in by the 2nd quarter of the year. Any recommendations for a 1st kit to prototype will be welcome.

[Brian_H]

I think those are AEB units - https://www.aeb.it/en/product/injections-mp48/ should find the software to download there. If they are not AEB then maybe the King software would work with them as thats the other possible one (same units, different firmware loaded on them)

They do seem to be far cheaper than you'd expect compared to https://lpgshop.co.uk/4cyl-ecu-aeb-mp48-non-obd/ for example.

You need quite a bit more kit than whats on that listing - Vapouriser, injectors, tank, valves for tank to match tank, Filling point, pipework under the car, level sender and shut off solenoid and filters for the front, plus pipes/hoses for the front end. Then you have some retaining clips etc to get to finish it off. Plus flashlube depending what your converting may be needed?

Biggest problem with smaller cars is getting a tank to fit and give you enough capacity at the same time.

As far as I can tell, MP32 lacks some features of the mp48 - though its not very clear what exactly. https://nazorati.com/en/product/lpg-kit ... -kit-4-cyl has a little bit of detail on that. Hopefully Simon or someone else might be able to tell you more on that!

[LPGC]

I could be wrong but I believe the MP32 uses an AEB025 pressure sensor while the MP48 uses an inline MP12T pressure sensor, and the MP48 features OBD connectivity while the MP32 does not.

The AEB labelling probably implies AEB software will work, though they could use other AEB software such as GasItaly, or King.

For a long time in the past if the system was Italian (and not BRC) we could presume that it used AEB2001 (4 cyl) or AEB2568 (8 cyl) electronics.
Then came a few oddballs such as OMVL Piro, usually short-lived.
Then came the AEB MP32's and MP48's.
More recently they've moved on to MP6C and other ECU's which need different software, there's a confusing range of software.. it is brand specific (as it was in the past) but sometimes you'll need to use software for a brand that doesn't match the label on the ECU (rare in the past, except for the home brand AEB / GasItaly labelled ECUs), even if you use the correct brand software there are lots of ECU revision / software version incompatibilities. If you didn't fit the system yourself it can be a pita even finding the correct software to use for an MP based system.
Some brands that traditionally used AEB electronics now use the same internal ECU hardware (but different firmware) to traditionally competitor systems such as BRC systems. The modern Seq32 BRC ECU doesn't bare much resemblance to traditional BRC ECUs. There are other oddballs (I'd class Romano Antonio as one).

There are many makes / models of LPG electronics, MP32 and MP48 are just a couple of different electronics made by just one manufacturer (AEB).

In the past someone could book in for diagnostics / servicing on say an OMVL based system and you'd know it would either be an open loop mixer system, an OMVL Millenium (AEB175) based system, a 'C' based system (stand-alone none-slave pulsed LPG injection system), AEB2001 (4 cylinder slave sequential ECU) or AEB2568 (8 cyl slave sequential ECU). You'd be able to connect to all those with the same cable and around 5 versions of software of which you'd only regularly need 2 versions of software (Millenium and V6 of the sequential software), or if it was an older ECU you might need V3 of the sequential software, or (rarely because the systems were shortlived) a couple of versions of C software. Then came Piro and you'd need a different cable for that, you might also need a few versions of Piro software, pot luck on which version would work. Now with the MP ECU's it's again pot luck, you might try all the OMVL MP software versions and none might work, then you might have to try other AEB brands of software for MP6s and try all the different versions for each of those until, if lucky, you find the one that works. I recently effected a calibration fix of an MP based OMVL system without even managing to connect to the ECU using any of the many versions of software I tried, must have spent the best part of 2 hours trying different software and phoning around suppliers for more different version numbers / brands of software that would hopefully work. When none worked I effected the fix by manipulating pressure and vacuum reference, which got fuel trims much better and the car driveable on LPG (when it came in to me it wasn't even driveable on LPG but it had apparently been like that since it was fitted!) but unable to make perfect without the software.

A lot of the formerly common name ECU based systems are now the minority and they change firmware / software / consistency with labelling (does the brand of software you're supposed to use match the label on the ECU - which even if it does won't tell you the software revision number / version that will work) regularly. Which makes them a pita lol. Even if all other aspects were equal (ECUs offered same controls and performance) I prefer to know where I am with ECU's and you best know where you are with ECUs made by the manufacturer who also labels the ECU. E.g. KME makes ECUs and they have KME labels on them, same with Stag and a few others. At one time there was a firm using KME electronics called AFC, it was a pita getting hold of software for AFC. AFC was solely distributed by a firm in Northern Ireland who wanted to keep controls of the installers that bought from them and didn't want to allow access to the software to anyone who wasn't one of their installers (I got a copy but it was a pita getting it). The same happened with a lot of systems that had a narrow supply chain, Lovato was one example, another (I forget the name, not Europegas but a similar name) was a system fitted by a small chain of UK installers (they had an install shop in the South and another in the North), when they packed up and moved back home to the continent nobody had the access codes to the ECUs they had fitted. They then started selling access codes for individual installs on Ebay for a high price.

But you should be able to get software for an MP32 or MP48 easily enough.

[Brian_H]

Micromise is probabbly the other one you mean Simon?

It might be worth asking the seller to advise on the software? It does seem a bit suspiciously cheap to me though.

[Hloni]

I've done just I've 13 000km since the conversion. 80-90% of that distance is on LPG.

This week was the 2nd time I got this error through my main ECU.

Subaru Outback 2005 2.5L EJ252 NA ECU code

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Any ideas what could be causing it, or how others have navigated around it? It's a "lean mixture" code

[LPGC]

Any ideas what could be causing it, or how others have navigated around it? It's a "lean mixture" code

I'll refer you back to my post #13 on this thread... If the map you pictured gives near correct fuelling on this engine then the combination of injector type, nozzles and pressure don't flow enough gas for this engine.