Converting the VR6 to run on LPG

[donpulsar 0]

I think diesels can be done but only a few company's will even look at them, & I believe it's down to the fact that in order to run LPG a diesel still needs 70% diesel to 30% LPG to work. So you do save fuel, but it takes a longer time to make back the initial outlay. Modern diesels (i.e Direct Injection) can be v.economical so maybe the only way to do it is to make your own Biodiesel? If you have petrol vans and do a lot of mileage it's prob worth considering.

As for the car's mpg on petrol, no doubt it is a little better on petrol but seeing as I had the car for a week before getting it done I've not got much in the way of pre-conversion figures. It's a fact that you even tho the octane of LPG is higher, you need to burn a bit more of it to produce the same power as petrol so I'd say a 10% drop is realistic, but when you're paying 1/2 price for the fuel, you can handle a drop in economy!

There is another benefit in that LPG is a cleaner burning fuel so it should help clean built up cack outta the engine :-)

I'll be at a VW meet tonight at the Scawsby Mill (near the A1 Jcn 37, address : Barnsley Road, Scawsby, Doncaster, South Yorkshire DN5 7UB) from around 8pm if anyone who's local wants to pop down & chat in person? :-)

[donpulsar 0]

And may have to give some iridium plugs a go once mine come up for renewal!

[hvr6 88]

apparently you cant really LPG diesel Stiggy, LPG develops more power further up the rev range diesels engines aren't designed to do that so too complicated to LPG convert it, gains too small see...

http://www.go-lpg.co.uk/diesel.html

[85jas 0]

Thought I'd give an update on how the LPG conversion went! Got lots of lovely pictures too :-d

The conversion has been done, and I’m currently running on gas – saves a small fortune, I did ~500mi this weekend – Cost me £70 instead of £95 (ish!). The conversion was £1150 plus £35 for the control software and cable and £20 for a full tank of gas. Normally I do 31mpg on the motorway, and coming back from Cardiff - Southampton I got 22mpg. After doing 500 miles this weekend I did my first remap, so hopefully things will improve a bit, though I don't see myself getting more than about 25mpg. Still, much cheaper than petrol, and with the 48L tank I got installed probably around 250 miles for £30!

Overall I think Profess did a pretty good job, especially considering the price. I turned up at 8.30am and the car was finished by 7.30pm. The manager and most of the staff are engineers from Poland which is excellent seeing as some 20% of the car miles done in Poland are on LPG! I’m told the job on a golf VR6 is slightly trickier than some other cars as they have to drop the petrol tank to bolt in the LPG tank and have to temporarily move the radiator forwards to install the injectors. Anyway it was done in 11 hours, pretty good considering how much needed to be done! They put the filler cap in the plastic trim on the back bumper just behind the right wheel and installed the gauge / button on a blank plate on the centre console. The job under the bonnet is very neat too, they’ve wrapped the wires, cable tied everything nicely, overall a good job. However the fuel gauge permanently read full on the way home – more about that below!!

However there are a few things which they could have done better. I took it to P+T Automotive services in Macclesfield (01625 502346), they do LPG conversions and it is where I’m buying my gas at the moment. The owner (Ian Swindells) is a lovely chap, and was interested to see how the install was done. He managed to sort out the dodgy LPG gas gauge, they had forgotten to plug the wire into the fuel tank! Anyway he pointed out they had installed the gas tank the wrong way round with the pickup at the front of the tank. The gas pickup should be at the rear of the tank so it can pick up gas when the tank is nearly empty and the car is going up a hill / accelerating. However no great shakes, I’ve booted the car around with only ¼ tank of gas up the country roads and had no problems (yet!). The other thing they didn’t do is jubilee clip the tubes which connect the gas valves to the injectors or the tube which connects the vaporizer to the manifold vacuum. That’s on my list of things to do! However the entirety of the rest of the install (in particular the coolant system modifications which run to the vaporizer, very important!) have been done very well with jubilee clips and good quality piping and T connectors.

Anyway now to the software and controller. Ian told me that they don’t use the AC Stag system which Profess install as it is a kit system more directed at the amateur self-install market. As such the system they install is diagnosed and tuned by the garage, at the garage. Personally, having had a good play with the software, I really like the ability to change the settings and I have already started to remap the gas system and am in the process of calibrating my fuel gauge (update - done!). They install the system to run somewhat rich and after the system has bedded in after 1k or so they retune to get better economy. Clearly this is a (y) VERY GOOD THING (y) as the system naturally leans out as the gas filter beds in (apparently!) so the way they do it doesn’t bugger the engine.

Driving the car is very similar to petrol. The car sounds a little throatier, I think the throttle response might be slightly quicker (may be subjective, that lovely placebo effect!) and the engine sounds soother and more regular but there's very little difference in the drive. I’ve set up the changeover temperature to 20 deg.C and that seems to work well. The VR heats up so quickly that, at the moment from ~15deg.C, it takes some 3-4 minutes to come to temperature.

In conclusion I think Profess’s job was pretty good, and certainly given the price and the time taken is well worth doing. If you’re happy to have a fiddle after they’ve installed it then this is the one for you! There are a few minor issues regarding the finished job, the most important (in my eyes, as I can’t easily fix it myself!) is the fuel tank being the wrong way round so it may be worth mentioning that to them before they do it. They’ve done a couple of golf VR6s, and done the conversion on other VAG cars which use the VR6 enignes so they know what problems they may encounter before they do it…

Anyway, hope this has been useful! Now for the pictures Be sure to have a look at the screenshots of remapping shenanigans at the bottom!

Jason

Fuel Gauge

48L toroidal tank. It sticks up about 6in. into the boot.

LPG pickup, regulator, primary gauge and emergency release valve. The gauge is pretty neat, there's a magnet attached to the float which causes the magnetic needle to rotate. This in turn is connected to a 90ohm variable resistor / voltage divider to provide a voltage to the controller. To calibrate just rotate the whole dial against a magnet and watch the voltage change!

Where is everything???

Vapourizer and Filter. Note the tap off the vacuum to control the gas injection timings.

3 of the valves mounted to the manifold

Main valve, Serial cable connector and Pressure transducer (black box hidden just under expansion tank)

The business end! The gas injector sat snugly next to the petrol injector

ECU mounted next to the battery

Fuel map as received from the installation. Blue is petrol, green is gas and the orange line is the multiplier setting (left-hand vertical axis). Injection times are on the horizontal axis, MAP on the vertical axis.

Eeeek! Proper, proper rich! This was my first attempt and I completely screwed up the map, needless to say.

Better! Back to square 1 (recalibrate at idle), then tweak a little away from lean. Getting there...

Much better! I'm gonna leave it like this for the time being and keep a close eye on it, make sure nothing crazy happens in the next few hundred miles. With the map set like this there's almost no difference whatsoever in feel when driving the car... I wouldn't be able to tell the difference if you hid the gas gauge and gave me some earplugs! Took a little while to get the map looking like this, still, I need no excuse to drive up and down the dual carriageway at WOT making that poor guy in the 318i wish he had a bigger engine... (a) (6)

[jasonoldy69 1]

Good read. Might consider converting in the near future

[jamiehamy 0]

Looks like I'm next in line for this for the Corrado. Will post when done.

EDIT - Booked for next Wednesday. Long drive to Wales from Glasgow!

[85jas 0]

Good on ya

[jamiehamy 0]

Well that's my Corrado VR6 now running on LPG. I'll not go into too much details as Donpular and 85jas have covered really well.

The guys at Profess did a really good job. Corrado was more tricky than the Golf's as there is virtually no room between the manifold and the radiator fans. Nonetheless the job looks really good, very neat and tidy considering everything that goes in.

The boss is a really helpful guy and was very keen to address some concerns i had with the install. I get paranoid with people working on my car, but happy everything was done correctly. They do so many conversions, that they really do know their stuff inside out. Having watched them operate for a few hours, i would not hesitate to recommend them, which is high praise from someone who can't stand most garages and their practices.

On the trip back up the road i got 25mpg straight away. I've not done any tweaking so far, will wait until 1000miles. That said, it runs so well i don't really feel the urge, but curiosity will get the better of me!

I had a 43litre tank in the spare wheel well, which takes about 38litres. This gives me at the moment a 220mile range.

Switch over to gas is absolutely seamless. Performance wise, I've not really managed to detect a difference, but will rolling road at some point to work out. The can is certainly smoother at cruising speeds, engine just purrs.

I feel it's money well spent and lets me enjoy a V6 for the cost of a diesel. I test drove a few diesels and realised i couldn't live with one on a daily basis.

Not much else to say, I'm a happy bunny and feel quite smug

Please feel free to message if you have any questions.

[jamiehamy 0]

Just thought I'd add a wee update. 6months and 10,000miles later, still running without issue on LPG. Not has so much as a misfire from it, getting about 24mpg average.

I rarely tweak the system anymore, as I find playing a lot with it seems to cause see-saw results. Little and rare is my motto now!

About to embark on a trip to Croatia and Bosnia, so will pile on another 4000miles, making me near break even point

[jamiehamy 0]

20k miles later, still going strong. Installed a software/firmware update to the STAG system which has helped improve performance. Getting about 25mpg mostly, sometimes up to 27mpg.

Plugs are still in good condition, they were fairly expensive but lasting the course

[Antihero1981 8]

how would this perform on a charged vr6? now that i would be intersted in

[jamiehamy 0]

From anecdotal feedback, I reckon it should work without too many issues. The LPG ECU piggy backs onto whatever ECU the car has, so you would, I believe, focus making sure the LPG hardware was physically capable of dealing with the required power output (bigger reducer//injector nozzles etc...) and install the LPG as normal.

The LPG ECU will simply take the injector times from the petrol ECU and put them through the LPG injectors leaving the petrol ECU unaware of what is going on.

I've often toyed with turbo'ing the Rado and with LPG, would be a hoot!

Someone already runs on on LPG, joni_vr6 maybe?

[hvr6 88]

my audi is 1.8t LPG no probs

[jasonoldy69 1]

Well, I said earlier in the thread I was going to convert. We'll see what happens in the next 6 months.

I've had a quote from Auto Gas Yorkshire, which are based in Hull, about an hour from me, £1500. This includes BRC equipment, which they assure best quality (3yr warranty). I asked if they've worked on a VR before, and they've worked on Ford Galaxy versions.

Looking at the PDFs they've sent, the tank is a cylinder that sits behind the rear seats. Can I ask, for those that have the tank sat in the spare tyre well, where's your spare tyre?

They've also said it will take them at least 2 days (free loan car), so I'm shocked some of you have had it converted in a day?

How did you find Profess? Is it me, or are these gas fitters very hard to come by? Where do you search for them?

Has anyone had the recommended 12000mile service yet?

[donpulsar 0]

Converting the VR was one of the best things I've done - currently paying 69.9p - 71.9p/litre!

Had mine done at Profess in South Wales - found them via Google - http://www.professautogas.co.uk - took a day to do the VR but its a nice part of the world so turned it into a mini holiday!

They have a small army of fitters that know what they're doing, so the job was done quickly (dropped car off 8.30am) & when we returned to pick it up at around 3-4pm they were just finishing off the mapping and not had a problem since it was done.

My tank is a 60 litre (full capacity 45 litres) doughnut tank. Spare tyre either lives in the garage or in the boot. And the best thing was their price - I paid about £1100 2 years ago which was way cheaper than any competition & now they've reduced the price even more to £799...bargain! :-d

The only "shock" to me is the fact that a place needs your VR for 2 days and wants to pull your pants down to the tune of £1500! You'd save a small fortune by driving to South Wales, booking a night or 2 at the local TravelInn & getting you VR converted there. I can't recommend Profess enough!

Before you have it done (wherever you decide!) make sure your ignition system is up to scratch, leads, coilpack/dizzy etc as the LPG needs a strong spark! As for the servicing, Profess gave me 2 filters so I can change it myself when the interval happens.

And with us all driving VR's...the LPG kit quickly pays for itself!

[AxlFoley 5]

I had mine done at profes autogas I'm not sure how many miles I have done, but it runs fine, it is due for a service though.

[Pieman 0]

I've been running LPG of a few years now and have never looked back.

I'm now looking at turbo'in the Caddy on LPG. It should be very easy.