Thinking of going LPG but need advice from BMW or VW owners

[wizard]

Hi All,

I am new to this but have had an interest in lpg due to the fuel economy costs.
I am planning on getting a big car but wondering how the hell will i be able to afford to run one unless its on lpg.
I am thinking of going for a BMW x5 3.0l or a VW Toureg 3.0l and will convert to lpg. I may possibly go for one that has been converted already but lets see.

Since being on this forum i have read nothing but negative posts about problems cars have been having since a conversion, like mechanical issues so i am not sure if lpg is the way to go.

Questions i want to ask.
Is there anyone on this forum that has any of the 2 cars above?
Have you had any issues with your conversion?
Have you really saved that much since converting?
What should i look out for if buying a car that has already been converted?
I am located in N.London (Enfield) area, is there any reccommended installers around here that i could contact for advice?

Any advice will be much appreciated.

Thanks
Wizard

[Gilbertd]

As this forum is predominately used by people who are installers, LPG DIYers and knowledgable amateurs who give advice to people who have problems, it does make it seem that there are a lot of people with problems. What you don't see are posts from the thousands of people who are happily driving around on LPG without issue, they have no reason to come here in the first place! You are in the minority by doing your research first rather than wait until you have a problem and finding that Google points you in this direction. I've neither of the cars you are asking about but after 3 cars and well in excess of 100,000 miles on LPG, I wouldn't have anything else.

[SnoozyBMW]

I had my 2007 BMW 3 series converted a few years ago by Anglia Autogas and have never had a problem so far.

The car achieves similar mpg to petrol (maybe 5-10% less on LPG) and drives otherwise the same. I had Versus system installed: http://www.versusgas.com/

This has been a good quality system and has aligned with the BMW well. I was looking to choose between BRC and Versus. Prins systems have the premier reputation.

I notice Anglia Autogas/Autotech have also done BMW x5, see here: http://www.autogas-kit.com/index.php?ma ... cts_id=117

[Gilbertd]

BMW engines convert well and don't give too many problems if done properly. The later ones can be picky on injector placement due to the additional idle air channel. If buying ready converted check for documentation, a certificate (or that the car is on the LPG register), that the fuel type has been changed in the log book and that it runs perfectly OK on gas. Don't believe a seller who tells you that it works fine but the tank is empty so you can't try it running on gas. That means it doesn't.

[Morat]

BMW engines have nice hard valve seats so they don't need flash lube, and my experience of a professional installation on a 3.0 BMW (M54B30 engine) has been really good. There was one initial problem but it was sorted while I waited and we haven't looked back since.
Try and find out which exact engine you're looking at, and search for it on here. You'll probably find problems, but you'll be learning from other people's mistakes.

I would say (in my limited experience) that the make of the LPG system is less important than the expertise of the guy fitting it.

[1975bay]

Hi I have Just had my 2001BMW X5 converted to gas.After a few problems,and the rubber gasket being sucked into the in take its now running good.as for mpg it to early to tell but £53 of gas and £20 petrol gets me 220miles (lots of short trips using petrol)

[antimony]

Hi I have Just had my 2001BMW X5 converted to gas.After a few problems,and the rubber gasket being sucked into the in take its now running good.as for mpg it to early to tell but £53 of gas and £20 petrol gets me 220miles (lots of short trips using petrol)

That's about 33p per mile!
Before I converted the 530i, petrol was costing me 25p per mile, now with gas it's down to 14 or 15p per mile (according to fuely.com)

[Gilbertd]

Hi I have Just had my 2001BMW X5 converted to gas.After a few problems,and the rubber gasket being sucked into the in take its now running good.as for mpg it to early to tell but £53 of gas and £20 petrol gets me 220miles (lots of short trips using petrol)

It must be lots of short trips. I can do that sort of mileage on £45 worth of gas and no petrol, and that's on something with a much less high tech engine, worse aerodynamics and more weight.

[pyro225]

BMW all the way, had my 328ci similar engine runnning BiGas, my 535i running BiGas, my M5 running Romano and my M6 running BiGas... all once finally set up drive well and never needed flashcube

[Coolhand Luke]

I ran a 530i with a Prins system for 4 years. Never any problem with the LPG system, hard valve seats so no flashlube required, but I had some issues with parts failing in the engine cooling system (water pump, radiators, expansion tank etc).

Whether this was anything to do with the LPG or simply due to the age and mileage of the car (or my driving style.. ) is not known, but LPG does burn at a higher temperature than petrol, and my BMW mechanic said he's often seen cooling system issues on converted BMW's.

My advice would be to look for a car that has had the cooling system overhauled already, or be prepared to do it yourself at some point.

[Gilbertd]

but LPG does burn at a higher temperature than petrol

It does but it's only 20 degrees or so higher at around 1700 degrees. So negligible as to be of no relevance at all, you'd get higher temperatures than that on petrol under some circumstances.

and my BMW mechanic said he's often seen cooling system issues on converted BMW's.

He's probably also seen the same problem on non-converted ones too but has just put that down to mileage rather than be able to blame the conversion on converted ones. BMW engines, mostly 6 cylinder ones from the 1980's and 1990's, did have weaknesses in the cooling systems anyway. Not bad enough to get them a bad reputation but it wasn't uncommon. They would crack cylinder heads too if you cooked them in a big way, Euro Car Parts used to do a roaring trade in replacement heads.

[Morat]

but LPG does burn at a higher temperature than petrol

It does but it's only 20 degrees or so higher at around 1700 degrees. So negligible as to be of no relevance at all, you'd get higher temperatures than that on petrol under some circumstances.

and my BMW mechanic said he's often seen cooling system issues on converted BMW's.

He's probably also seen the same problem on non-converted ones too but has just put that down to mileage rather than be able to blame the conversion on converted ones. BMW engines, mostly 6 cylinder ones from the 1980's and 1990's, did have weaknesses in the cooling systems anyway. Not bad enough to get them a bad reputation but it wasn't uncommon. They would crack cylinder heads too if you cooked them in a big way, Euro Car Parts used to do a roaring trade in replacement heads.

That'll be the M20B25 from the E30 3 series. Yep, they can crack heads easily if you let the water temp get into the red, the trick is to make sure you switch off if the needle gets to the top quarter mark (just before the red). The cooling system isn't bad overall, but the viscous fan clutch can fail and leave you overheating in traffic. It's gradual, so you should spot it before there's a problem but that does rely on people caring about their car!

On the upside, the rads don't bow and split and the expansion tanks don't go pop like they do on the E46 and E39.