Converting the VR6 to run on LPG

[donpulsar 0]

(Quick disclaimer before I start - I'm not an LPG Installer/Fitter/Rep & I'm not affiliated to any Installers/Fitters/Reps! :-) )

Prior to getting the VR, I ran a Subaru Legacy 2.2 Auto for 2 years on LPG & having had a bit of interest and the odd question about the LPG conversion I'm planning for the VR, I thought I'd start a topic to cover a few points & hopefully answer the odd question. :-)

What I'll also say is that if you don't intend in keeping your VR for more than a year, it probably wont be worth having the conversion done unless you do a lot of miles per month! However, the kits can be transferred from 1 car to another & you save on forking out for the hardware again, tho' be aware this swap depends on the cars being similar or smaller engined.

What is LPG?

(Blagged from wikipedia!) LPG is synthesised by refining petroleum or "wet" natural gas, and is usually derived from fossil fuel sources, being manufactured during the refining of crude oil, or extracted from oil or gas streams as they emerge from the ground. It was first produced in 1910.

It's been used since WW2 to power cars, machinery, heating etc. Some countries like Poland currently have a large percentage of vehicles running on it.

LPG has a higher octane than Unleaded/Super Unleaded so engines run smoother and can be tweaked on the ECU for more power (Some of the LPG ECUs' are fully mappable so timing can be advanced).

How much per litre is LPG?

It's not taxed to the same extent as petrol/diesel (e.g Shell, Balby Road, Doncaster - Unleaded 111.9, LPG 57.9). It's just over 1/2 the price of unleaded, & half the price of V-Power so depending on the amount of miles you drive it really can make a difference to your wallet to convert your car / VR to LPG.

Do I lose any power/mpg?

This depends on the LPG system that is installed - however the new installs have an intelligent ECU that may give you a 1-2mpg drop but give the same amount of power or more.

What does the conversion involve?

Basically a new, seperate fuel system is fitted to the car complete with a tank (doughnut shaped to go in the spare wheel well or cylindrical) & pump in the boot, pipework, a vaporiser to turn the LPG in gas, gas injectors into the manifold & a seperate ECU. The company I am going to for my conversion supply a fully mappable ECU for the LPG as well as software for it so it can be remapped to allow for more mods, power etc.

Where can I fill up with LPG?

Lots of places! The majority of Shell garages stock it, as do quite a few BP's, Morrisons, the odd Asda (Selby & nr Glasgow Airport are 2 that come to mind!) & the odd Tesco. Discount Roofing Supplies in Doncaster sell it & it's also available from numerous agriculture suppliers throughout the country. All LPG conversion specialists should also stock it. You should get a book with the conversion detailing what places sell it & for the sake of a few calls to builders/agriculture merchants & petrol stations you should easily be able to find out where sells LPG. A lot of Motorway services are also having it installed.

How much does it cost to convert to LPG, & what can I save?

Now the only problem with converting to LPG is the initial financial outlay. Each LPG installer has a different price structure, but I'm spending £1100 to have the VR converted (if it was a four cylinder GTi probably around £890). A lot of money in anyone's book but with a little bit of Maths I'm going to hopefully show where the savings (for me) come from.

(Please note that the savings will differ as to where & how you drive...if your car spends a lot of time crawling in traffic then economy suffers, same as if you nail it everywhere..whereas if you cruise a lot on A Roads & M'way's it'll return more mpg, for example the Legacy used to give me approx 220 miles per tank of LPG on normal driving, but would go up to 245-250 on long M'way runs.) :

*These calculations assume your tank is empty everytime you fill up, but it makes my calculations easier too!

Golf VR6

A tank of LPG holds around 45 litres of gas & at 57.9p a litre = £25.65 per fillup.

If my VR6 does 25 miles per gallon (or 25 miles per 4.454 litres) I will get 252 miles on 1 tank.

So the price per mile of LPG = Just over 10p per mile. (For ease I'll say a straight 10p)

To compare to running on petrol :

A tank of petrol holds 55 litres of Super Unleaded at £1.18 a litre = £64.90 per fillup

If my VR6 does 27 miles per gallon (or 27 miles per 4.454 litres) I will get 333 miles on 1 tank.

So the price per mile on Super Unleaded = Just under 20p per mile. (For ease I'll say a straight 20p)

I drive approx 12,000 miles a year ; on Super that's a cost of around £2400 for the year, whereas on LPG thats a figure of around £1200 for the year!

What this means is that within a year the LPG kit will have paid for itself and saved me £100 (Cost of conversion + fuel is £2300 whereas just petrol is £2400), then from this time next year onwards I'll be saving money everytime I fill up!

Where am I going to have my kit installed?

I'm heading to South Wales to a company called (Profess Autogas) who offer the complete conversion in approx 1 day. Both me & the Mrs are having our cars done so will be picking them up a day & a half after dropping them off. Having spoken in length to their engineers on the phone they came across as very knowledgable & just as important - very friendly.

We get a courtesy car for the time they have our cars & have on-site gas for when we're done!

They fit a fully mappable ECU to the car for the LPG and they have offered to show me how to use it and will also be giving me all the software, leads etc.

A quick search on Google should find numerous installers wherever you are in the UK.

Summary

Even though you fill up more often due to the slightly smaller tank, the difference in cost means that you can recoup the original outlay in a year or less & then enjoy big savings on your fuel bill after that.

Hope that helps! I'll try & answer any other questions people may have, but I can only answer from experience - I'm no expert!

[Nex 17]

out of interest, does this kit keep your ability to run on petrol? say your car runs out of LPG, will your car then turn over to petrol or is this an LPG and nothing else? if you get what l mean lol

[donpulsar 0]

Should have mentioned that! Sorry! :$

Yes, your petrol tank etc is retained and you can use both fuels, swapping between the 2 at will using the in-car controller that's supplied as part of the LPG kit. Most kits start on petrol, then once the coolant has reached 40 degrees or so the LPG switches on and turns the petrol off. If the LPG system runs out it switches back over to petrol.

Hope that answers your question!

[Nex 17]

that’s great and I must say l am now very interested

[donpulsar 0]

Good stuff!

I'll be updating this thread with further details - i.e what the gas place is like, a bit more about the conversion, what tank I'm having and where it'll be fitted, where the hell I'll be asking them to put the gas filler cap & then after that, how the VR drives with gas ( the 3 & 1/2 hour road test from S.Wales to Donny ought to do it!) & my initial impressions etc!

Roll on Sunday when we drive down there for an early start to get the VR & Colt to them for 8am-ish!

[p0u1 14]

i want to convert mine, i covered 25000miles last year so it would be worth it as savings are huge!

stupid how much money we need to spend on are fuel :-/

[bungy 2]

Sounds interesting but one consideration is the petrol starting. Through the winter and short journeys you'll use a lot more petrol than gas and so it will take a lot longer to recoup your costs. Most estimates for normal domestic use are 2-3 years. I realise everyones will be different and look forward to seeing your results and thoughts.

[donpulsar 0]

pOu1 - you'd be saving money hand over fist doing 25K a year!

bungy - Good points. To be honest in winter there's an extra couple of minutes for your car to warm the water up (which might equate to an extra mile or 2 on petrol), but I found that any difference in mpg is negligable at best.

As I mentioned above, & as you say, it all depends on where you drive, how far, times of the day etc...there's a lot of factors to take into account. My journey to work is approx 17 miles each way of country roads with no traffic lights and a handful of junctions. If the schools arent on holiday I wont go through town as there's way too much stopping and starting that kills the mpg.

Having already had 1 car with LPG I know it can work for me but as you rightly say everyone's different. Hopefully when it's all done and running on the VR maybe I can help save a few more people some money?

[donpulsar 0]

pOu1 - you'd be saving money hand over fist doing 25K a year!

bungy - Good points. To be honest in winter there's an extra couple of minutes for your car to warm the water up (which might equate to an extra mile or 2 on petrol), but I found that any difference in mpg is negligable at best.

As I mentioned above, & as you say, it all depends on where you drive, how far, times of the day etc...there's a lot of factors to take into account. My journey to work is approx 17 miles each way of country roads with no traffic lights and a handful of junctions. If the schools arent on holiday I wont go through town as there's way too much stopping and starting that kills the mpg.

Having already had 1 car with LPG I know it can work for me but as you rightly say everyone's different. Hopefully when it's all done and running on the VR maybe I can help save a few more people some money?

[bungy 2]

My daily drive to work is 17 miles each way and all motorway. I do get a fuel allowance though.

[p0u1 14]

do you think they will be able to make a vrt LPG because if i turbo my car and get it converted to lpg it would be a sick Eco friendly rocket lol, in theory they should be able to put it on any car.

[donpulsar 0]

The only change to run on a turbo'd car is the ECU / mapping and possibly bigger injectors? It's been done before ; Pulsars, Stageas & Legacy Twin Turbo's have all been LPG'd so there's no reason why it couldn't be done on any turbo'd car, VR or otherwise. Best thing would be to ring some local LPG installers & check with them.

[mike 6]

i saw a LPG vr6 on autotrader a year or so back, wish id snapped it up now lol, was going for reasonable money too. like 2grang...

the conversion alone costs about 1300quid iv been told?

theres a v6 4mo lpg on uk mk4 site too

[jamiehamy 0]

Looking forward to hearing the results, I'm considering this for my VR6 Corrado. Keep us posted!

[p0u1 14]

if you go on ebay theres a few auctions for lpg, if your lucky you can get it done for under a grand

[85jas 0]

Hi! I was wondering how you got on with your LPG conversion... Everything running ok? I'm seriously considering getting this done.

[Lukey. 381]

when i had a focus ST i used to frequent the STOC, a guy had his ST LPG converted and it burned his engine up in very few miles. That said a few others had and had no problems, i think the jobs only as good as the guy doing it

[donpulsar 0]

Right then, its been just a couple of weeks since the conversion so here's my update!

The company I took it to - Profess Autogas

They offer a 3 years manufacturer's guarantee on parts & lifetime warranty on their workmanship with unlimited mileage.

The LPG System -

The system I had fitted is an Autogaz AC with Stag 300 ECU, with a 60 litre (water capacity)/45 litre (LPG capacity) doughnut tank mounted in the boot. A doughnut tank is a very common choice as it fits nicely where the spare tyre sits so boot space is more or less unaltered (spare can either live in the boot or just carry a can of tyre inflator) whereas the cylindrical tanks take up room in the boot (but are quite often used underneath chelsea tractors!).

The condenser sits under the bonnet and is hooked up to the engine's water supply ; once a preset temperature is reached (20-25 degrees) this switches the LPG system on & converts the LPG fuel into a gas.

We were informed that the condenser is set initially to overfuel, allowing it to bed in and not underfuel the car.

Over the initial 1000 mile period we were told it would lean itself out & for us both each tankful has increased in the amount of miles it's gone...my first proper fillup in Doncaster lasted 200 miles & my second fillup lasted 220 miles so hopefully this tankful will last even longer! (But even at that which equates to just under 22mpg I can't complain, I'm paying 58p a litre!)

The system master switch (with built in LPG gauge) is mounted anywhere you like in the car. (see pic below)

The ECU is a fully mappable unit that as well as allowing you to remap the LPG also show diagnostics for other items of the car such as Lambda sesors, fuel injectors etc. More pics to follow once I've set the software up! (I need to see if it allows mapping of the ignition ; I could advance the ignition for the gas to give me more power...but its early days yet!)

The Install -

We got to Profess Autogas Monday morning & everyone we dealt with was friendly & no question went unanswered. We told them where we wanted the LPG filler's & the Gas On/Off switches to be fitted, then left the cars & took their courtesy car into Caerphilly (nice place, recommend going!).

Many places say that they need 3-4 days to install & setup an LPG conversion, but Profess say they do a full install & setup in a day & we had both of ours finished, mapped and completed on the Monday. Having seen these guys at work they're certainly an efficient lot. They generally do 4 cars in a day & have a large team of staff so there's 2-3 guys per car. Another thing that makes their install quicker is the mapping of the LPG.

To map the ECU - First an auto-calibration on the Gas ECU allows it to read the car ECU's existing fuel map in the ECU, & produce a matching gas map. The car's then taken on the road & the Gas ECU map is is then tweaked via a laptop hookup so its curves match the petrol curve. (The software and cable are available for £35 from Profess, I picked one up as S.wales is a long way to go to tweak things!)

Install Pics -

On the outside of the car the only thing to hint to LPG is the filer cap, which i had located recessed slightly under the bumper - didn't want by back bumper drilling!

(Just need some black paint to hide the visible bits of brass!)

Inside, the only clue is the control switch mounted to the left of the steering wheel. Simply start the car, & as soon as the water temp reaches a preset level (25 degrees) the LPG switches over. To manually switch back to petrol, press the "b/g" button. Simple!

(The switch was put in a hole in the trim used by a previous immobiliser, hence the small drill mark still visible!)

The install under the bonnet is very neat with only the rail the injectors are mounted to needing a bit of black paint!

& a closer shot (& yep they do clear the bonnet, with only small indents into the soundproofing!) :

The ECU & Condenser are visible here (top & bottom right) :

ECU Diagnostic, Reading & Mapping Port :

The Drive Home -

The drive back from Wales went well, neither of us having any problems & both car's performed as well on LPG as they had on petrol and from there to home cost me £25 in LPG :-)

Experiences over the weeks after the install -

Having spent a lot more time behind the wheel I'm pleased to say that there's been no drop in performance, it still pulls like a train through the gears & seeing as LPG has an octane rating of 114 that probably helps! I'm also confident in saying that the VR sounds a bit throatier & runs even smoother when on gas!

The spare tyre will be living in the garage unless I plan any long trips - no point filling the boot and lugging the extra weight all over (and why is the VW spacesaver so much heavier than the 1 in my previous Legacy ?!) Will be replacing it with a can of tyre inflator and see how we go from there (& I'll remember to keep my AA card with me too!)

As i write this I'm geting closer to the 1000 mile mark (this week I'll be be installing the software on my laptop and giving the system a checkover and making any adjustments to the fuelling that the mapping may show).

Will have more pics soon & hopefully I've not missed ote out!

:-)

[85jas 0]

You might be starting a trend donpulsar! Good update, thanks.

I booked in my vr for conversion in with Profess Autogas for a couple of weekends time (2nd oct), they had no problems doing the modifications on a saturday. Gotta leave Macclesfield at 6am to get there at a reasonable time, but hey ho... Caerphilly is lovely like you say, might check out the castle... The guy I spoke to on the phone (Eddie) was really helpful and answered all the questions I could imagine!

Question for you (don), which size tank did you get fitted? Does it sit flush with the spare wheel cell or did you choose a slightly larger one? I'm tempted to get the largest tank I can sensibly fit in the wheel cell, though I doubt I'll be doing more than 200 miles non stop! I'm a bit loath to loose loads of boot space to a tank, every cubic foot is useful I was gonna ask if the filler fitted next to the petrol cap (as their website shows some audi's have enough space to do that) but your pics have answered that question

Let me know how you get on with the software for the ecu. From the pdf manual downloaded from the autogaz website it looks like there's plenty you can do, hopefully there are some performance tuning options hidden away somewhere! It seems like the system has been designed to follow exactly what the original ecu is diong though, will be a pity if changing the ignition advance isn't option (particularly due to the octane rating of the gas!)

Just a thought, I remember reading somewhere that you can't take an LPG retrofitted car on the eurostar or some ferries... I looked around on the company websites and can't find a thing! Any thoughts on this?

Anyway I'll post updates on how I'm getting on, due to do a good few k's in the coming months so I'm looking forward to doing them cheaper :-d

[jamiehamy 0]

Thanks for the update Don, much appreciated. My Corrado VR whilst economical @30mpg is doing about 14k per year. I really need to bring costs down and this looks like my best option. I simply drive (and enjoy driving) too much to have a 'cheap runaround'.

- You say you get 22mpg on gas - what were you averaging on petrol before install? I know they say 10% reduction, but was wondering what you were getting.

- Do you know how easy the kit is to unplug if working on the engine? e.g replacing tappets etc...

Looks forward to hearing from you,

Thanks, j

[hvr6 88]

got the Audi 1.8T converted, 27 mpg on gas now we were getting 35 on petrol but will have paid for itself in 8 months :-) handy when you need a support vehicle for shows...

and apparently using Iridium spark plugs is supposed to be better on LPG

[J5KE F 0]

A Very interesting and well presented read! Does any1 know about diesel / lpg Conversions..? My fuel bill for the vans is currently 2-2.5k per month so would be very interested in getting them done!

[squid1 0]

wow that a big fuel bill for a diesel vr sick u do a lot of drivin i take it lol

[J5KE F 0]

Yes fella, 6 vans and the uk and ireland cover, it soon adds up!!

Even our local service van can do 150 miles a day in the heat of summer!

[squid1 0]

wow tht a lot are 3 work van go out neally everyday but still on 1k lol, deff think if u could this would b a gd idea for u thn