LPG 540i

[Apache]

Could anyone tell me how one of these will perform, will the economy be that much better, will the performance be comprimised? It's a 99 4.4 auto

[Methane Bloke]

On my experience of having an LPG car, running costs will be cheaper, although saying that, in 65K miles I had to replace the cat and two lamda sensors, which could of been down to the gas?. Fuel consumption dropped from 30 overall to 23 (but the fuel was half the price). Range, on gas wasn't great either, although I got to know where the garages with LPG were. Power suffered as well dropping about 10% I would say.

Switched back to a diesel now and getting the same fuel cost per mile.

Regards

Chris

[Apache]

Thanks MB, what car was that on and what do you call 'poor range'?

[Methane Bloke]

Car was a MG ZT. Fuel tank (gas) was around 50 litres (usable) so I used to get around 230 miles between fill ups, which was a bit of a pain as I averaged that most days of the week.

My mate has an LPG Range Rover V8 and reckons he gets around 12 to the gallon on gas!

Regards

Chris

Edited by Methane Bloke on Saturday 11th August 16:44

[Apache]

12 to the gallon!! christ........wonder how a 4.4 V8 540i will perform then

[ironictwist]

If it's any help, i've recently snapped up a 328i that had been LPG converted. Previous owner had eletronically isolated it due to a fault, 60 quid later at Arun Autogas in Sussex & im up and running on LPG. Starting my first week of commuting with it today, 70 miles today and still going great.

On Saturday night i topped her up as I planned to spend all of Sunday driving, did 120miles on sunday to see how it felt then filled up again to full on Sunday night, was about the same i put in Saturday night to top her up again, aka 18 quid. But will let ya know how it goes over the coming week, performance wise, it still is awesome

Oh one another thing which doesnt help me though is the system on this BMW of mine is a crap Landi system installed 7 years ago, the newer seem far better and assuming you have a newish system you should get better results than i have thus far. Having said, I think it's a revelation regardless.

Edited by ironictwist on Monday 13th August 20:59

[Apache]

thanks, will be waiting for your updates feller

[Slurms]

I gave some serious thought to getting an LPG conversion on one of the high capacity engines before I bought my clubsport.

As long as you get one of the new multi-point injection systems you should have no problems. I've had friends running on both systems and they have reported less power loss than the single point injection systems and improved economy.

Lots of information on this site www.go-lpg.com

[ironictwist]

The 328's out of action for this week i fear

So far managed 140 miles, not much at all. The lights that indicate how much of the fuel is left have all gone bar one which is flashing which basically means "running out soon". But having spoke with the guys at Arun, they say that this specific indicator will be very inaccurate, so just keep going till it runs out, which I plan to once the old girl is all better from her recent..erm...incident :/

Edited by ironictwist on Tuesday 14th August 23:31

[Methane Bloke]

I would be very surprised to see an increase in economy!

The lighter density LPG fuel displaces air in the inlet manifold reducing the inlet charge and decreasing volumetric efficiency. It also has a higher oxygen demand than petrol as well (LPG stoichiometric A/F = 15.8).

Regards

Chris

[Shine-On]

I used to run a 1999 540i Touring on LPG through work. Acutal mpg on LPG was worse than on petrol, and the performance was not as good. Its a slight difference, but noticeable (although only really relevant if you were comparing against something else). The car did a lot of miles and generally got about 250 miles to a tank of LPG, which was a little less than it was managing on petrol. With the fuel being so much cheaper the conversion paid for itself pretty quickly, but wasn't without a few niggling problems.

Definitely a worth while thing to do i nmy opinion, giving a great car semi-sensible running costs.

[Apache]

So I figure your fuel bill is 2.3 times less using LPG?
or a car that normally returns an average of 25mpg will cost the same as a car returning 59mpg on LPG?

[Shine-On]

Not quite, more like if it was doing 25mpg on petrol, it would be doing 40-45 on lpg. You don't get double mileage/half cost (however you want to look at it). LPG has a lower 'calorific burn value', I think thats what its called. Basically you don't get as much energy for a given volume of LPG as you do petrol, so it uses a little more to maintain similar performance.

[Apache]

Ok, thanks.

[Alfie740]

when i baught my 740 (obviously the same engine), i considered doing the lpg thing. the more thaught i gave it, the more i decided not to. the initial cost of a little over £2000 for the correct system for the car i think is a little over the top - you need to do some serious mile to warrent that!! i can average 26mpg if i drive like an accountant's grandmother and i think that's just fine - and what a lovely big boot i have with no pikey tank in it!!

[matt-man]

Or in a 7 series, you usually have a pikey in the boot tied up!! lol