LPG fuel

A friend of mine has just had his Volvo converted to run on LPG and he is, to say the least, extremely pleased with the conversion. He has no obvious loss of performance and his fuel bills have been slaughtered.

He's trying to convince me to convert a '96 840 (4.4L) to run on LPG too. I remain to be convinced.....

Anyone else thought about this? Any success stories (or horrors)?

Griff

Reply to
Griff
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I know of quite a few large BMWs running on LPG. If you do a reasonable annual mileage in the car it's well worth it.

Reply to
John Burns

But it would depend on the taxation on fuels in the country as LPG isn't intrinsically cheaper than petrol.

Reply to
Dave Plowman (News)

Okay - so am I right in thinking that there isn't a significant risk of knackering the engine or catalytic converters etc?

Reply to
Griff

...or is the main risk not being able to find a garage that sells the fuel?

Reply to
Griff

In Germany, due to the high fuelprices, people are converting E38 740s and other big BMWs to LPG; Prins VSI appears to be the favorite setup, with Vialle also mentioned. Conversion prices run around 3k Euros for a V8, slightly less for a I6 (for a 728i for instance). So, in principle it shouldn't be a problem, unless the engine bay of an E31 doesn't leave room for the components. With fuel at E 1,40 and LPG at E 0,50 in Holland it's worth looking into... Hans The Netherlands

Reply to
Hans

Hmmm... 3k Euro to convert? Whats' the difference work out to be per mile of fuel and how many miles do you have to drive to break even on that gem?

Reply to
Malt_Hound

Depends on the respective prices of fuel and lpg, which differ per country. Also, mileage is about 20% less on LPG, so you'd have to calculate that as well.. And finally, road tax which is also different per country. So no easy answer, you'd have to do the math with your variables. In Holland, you'd be looking at about 15000 miles or so to berak even on the install.

Reply to
Hans

There's no risk to cats or anything else if your engine normally runs on unleaded petrol. You need to get a list of LPG garages though, even if only for peace of mind. If you're in the UK then there are a couple of web sites that have details.

Reply to
SteveG

Griff, I can't comment on BMW's running on LPG, although I'm seriously considering it for my '92 730. I do, however, have a 3.9V8 Discovery which was converted a couple of years ago ... and it's brilliant. This vehicle currently does about 800 miles per week with about 100 of those off-tarmac.

My observations are:

  1. There is no apparent loss of power on LPG. This may be because the Disco engine is only mildly tuned anyway and not as "highly strung" as a BMW engine.
  2. I get almost exactly the same fuel consumption on LPG and petrol (16 vs 17 mpg) and at just £25 for 80litres I can live with the difference ;-)
  3. The engine is notably smoother on LPG. Don't know why but it is. Acceleration is smoother with no flat spots - it just pulls like a train all the way to the red line :-)
  4. Running low on gas can promote backfiring in the air intake. This would probably wipe out the air flow meter but you should install a simple flap valve to prevent this from happening. When we first converted the Disco I had a blow-out valve put in the air box (the afm is pretty bullet-proof) but after the first blow-back found that it couldn't handle the volume of air involved. Fitting another one has cured the problem but if I was doing it again I'd go for the simpler flap valve.
  5. You need to have the engine running almost perfectly on petrol before doing the conversion. If there are any weaknesses in the ignition system they will be more apparent with LPG, which needs a stronger spark to ignite. Make sure the plugs, HT leads and distributor are all A1. On the Discovery I fitted Magnecor leads which have better insulation and conductivity properties than the standard Land Rover ones. Poor HT leads can aggravate the backfiring problem mentioned in 4 above.
  6. You need to run on petrol ocassionally to stop the fuel injectors getting all gunged up. I usually start mine on petrol and let it switch to LPG automatically when the revs go above about 1800 (the switch point can be adjusted via a laptop). Even in winter you can start up and blip the throttle straight away and it'll run fine. I never get a power drop at the change-over point.
  7. Choose your installer with care. Make sure he is LPGA approved and can give you a CofC for the installation because your insurance company will want to see it. The most expensive is not necessarily the best. Talk over the installation with the installer and get agreement about how things will be done - remember it's your car and your money so get the job done that you want. Also, get agreement up front that they will tweak the system for free over the first few weeks of use.

HTH

If you have any specific questions then feel free to ask.

Reply to
SteveG

Got my 1998 E36 318iSE converted over 12 months ago. 60 litre tank and gas injection. Only problem was when i disconected the battery to replace it and the LPG ECU lost all its settings and defaulted back to original settings. Quick trip back to installer and all's been well ever since. The only difference I notice is in my wallet each time i fill up. Currently saving around £35 BPS each time i fill up.

Go for it.

JohnP

Reply to
JohnP

Only until governments decide to increase the taxes on the fuel. Already a threat in the UK.

DAS

For direct contact replace nospam with schmetterling

Reply to
Dori A Schmetterling

Loss of boot space?

DAS

For direct contact replace nospam with schmetterling

Reply to
Dori A Schmetterling

Reply to
Hans

"" wrote: > Malt_Hound wrote: > > Hans wrote: > > > >> John Burns wrote: > >>

Had my 95 840ci converted to gas in June 94 not a problem at all cost £2000 but as I do 30,000 a year saving me loads :D

Reply to
mark000077

Dori there is no loss of boot space by fitting a tortoidal tank which is like a donut shape in the spare wheel space in my boot, if I get a puncture I just call recovery service, Mark.

Reply to
mark000077

Goes where the spare wheel was, never needed one, just call ATS mobile :)

JohnP.

Reply to
JohnP

Interesting solution, also reported by Mark000077. I agree that the need for a spare is not high. I call roadside services anyway, what with the nuts being jammed or it's raining...

DAS

For direct contact replace nospam with schmetterling

Reply to
Dori A Schmetterling

If the price difference vs. petrol is because of taxes, be careful that your friendly local government (there to help you) does not get wind of this and plugs the tax loop-hole leaving you thoroughly screwed and without even a dinner to show for it.

Reply to
GRL

I've owned a number of dual (LPG/Petrol, CNG/Petrol) fuel cars and found that on older ones if the ignition is advanced a bit the vehicle will run slightly better on LPG, and confirmed on dyno, but this was with older V8's etc. I'd hate to mess around with a conversion on a modern BMW, which is designed to run on petrol.

Steve

Reply to
Tbird-Steve

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