Calling all BMW x25i/x30i owners

[325i]

I'm looking to get my 2006 BMW 530i converted and I'm looking for feedback from current x25i/x30i owners.

I have estimated I will get around 17mpg around town on LPG and 30 on the motorway.

Does this sound about right? What are you getting?

[325i]

Any feedback?

[antimony]

Only filled up twice so far but it looks like I'm getting about 25mpg on gas compared with my long term average of 28mpg on petrol (2001 530i)

[Tubbs]

That's about what you would expect to see from a well set up system. In the region of 10%. It's pretty well behaved though the EMER system it has to be said. You don't generally get any nasty surprises out of it.

[325i]

Thank you, any more feedback?

[325i]

Any more BMW owners?

[antimony]

There are a few comments here
http://forum.bmw5.co.uk/topic/60075-lpg ... ge__st__30

[e301988325i]

2002 E46 330i touring 24mpg on gas over a few thousand miles.

[325i]

2002 E46 330i touring 24mpg on gas over a few thousand miles.

What sort of driving is this? Motorway, around town?

[325i]

In my calculations, I'm estimating that I will average around 20mpg on Lpg? Is this a reasonable estimation?

[rossko]

You might be thinking about this too hard - that's two months of potential LPG savings lost already. If it's not clear that conversion is going to pay, then its probably not worth doing for you.

[325i]

You might be thinking about this too hard - that's two months of potential LPG savings lost already. If it's not clear that conversion is going to pay, then its probably not worth doing for you.

My plan was always to convert in summer time.

By the research I have already done, I believe the conversion will pay off. But its nice if someone who has a similar car can comment on there running costs.

[e301988325i]

2002 E46 330i touring 24mpg on gas over a few thousand miles.

What sort of driving is this? Motorway, around town?

Mixed, car is used for supermarket runs and town, the Mrs can do 100 - 150 mile journeys on the motorway for work, now dropped to 23mpg with no accounting for petrol usage.

[325i]

What figures do you get purely on a long motorway journey? Is 30mpg possible?

[e301988325i]

What figures do you get purely on a long motorway journey? Is 30mpg possible?

If that motorway journey was down hill, with a tail wind behind and on the back of a recovery truck!!

Best over a tank is 26mpg, ours is a 5sp without the over drive 6th so is proabably worse on the motorway. Please bear in mind I don't have a 330i on gas to do 55mph slipstreaming trucks, the outside lane is where this car lives.

I got 35mpg on petrol before converting on the 200 mile trip bringing it home along A-roads, but that was mainly careful driving.

[325i]

Like yourself, I got 35mpg on petrol on a motorway run.

On Lpg, I was expecting to get around 28-30mpg.

[e301988325i]

Like yourself, I got 35mpg on petrol on a motorway run.

On Lpg, I was expecting to get around 28-30mpg.

As I said chap, 35mpg being careful on petrol. An honest average from beemer forums for my car on petrol is 25-28mpg, if I'm getting 23mpg on gas this is about right factoring in the -20% for LPG. The 325i maybe different but I understood it is a restricted 3.0L.

With LPG the more fuel you would be using the more the savings rack up, there's no point converting a 1.0L and driving like a Nun, it'd take a lifetime to payback.

On gas my avg is 13.8p/mile, now comapred to diesel (the realistic alternative to LPG) @ 144.3, our car is averaging the same as a diesel doing 47.7mpg, now realistic reports from forums suggest a 330d (comparable power) struggles to crack 40mpg I think it's win win for the M54 on LPG.

[robinthecheerful]

Greetings!

Dont know whether you went ahead with your conversion yet but only just picked up on this thread.
I have run a 2003 325i on lpg for about 11,000 miles since installation in Nov last year. Conversion was done by Autogas solutions in Hitchin with a BRC system.
I have kept record of most of my fillups and noted the cost of diesel to calculate equivalent mpg.

Best lpg mpg I get is around 24.5 worst just under 21 - some installers will tell you 10% or 15% difference lpg/petrol which is a physical impossibility considering the calorific value gas/petrol.
The biggest difference shows up on long motorway journeys where with petrol I could get 35/36mpg fairly easily cruising whereas lpg is around 24.5 thats 30% difference.
More local journeys petrol consumption increases dramatically to 27/29 mpg but gas only drops to around 21.

One thing that no-one ever mentions is that even these lpg mpg numbers are exaggerated as the car starts on petrol and only changes when warmed up. In winter that is a few miles and uses a lot of petrol from cold. Over the course of a 10,000 miles you will be suprised how often you have to fill up with petrol. Its one thing I didnt take into account.

In addition you have to consider the system has to be serviced once a year - prob only £60/80 but an additional inconveniec and expense.

When calculating equivalent mpg (if you had been buying diesel over the same mileage) of course it makes a big difference what the actual price differentials are but I have been getting the equivalent of 37 to 44.5 mpg. So worst for local journey best for long motorway journeys. Dont know how a 320d with me driving would work out but I suspect (from comparing notes with a friend who has one) it would be marginally better but not a lot.

People talk about payback time but actually if you are out to buy a car now the price of the petrol vs diesel car will cover most of your installation costs.
When I bought my 2003 car in Nov it had 37,500 miles on the clock, fully loaded (full leather etc), nice colour, fsh etc and it was £4100 - you can imagaine what an equivalent 320/330d would have cost and you wouldnt find one anyway that age/mileage.

Further upside of course is that a 325i is about a hundred times nicer to drive than any diesel - its much much smoother and quieter, goes well and the engine note is lovely.
Performance wise I feel no difference between petrol and lpg BUT my car does have some idle issues - a tendency to hunt up and down and sometimes its easy to stall.
These cars have highly complex vacuum/evap systems which lpg has a tendency to find fault with. The ideal would be to find an installer who is totally aware of any specific problems with your car version. My model 325i for example has a tendency to intake hose leaks and oil seperator failure. I had to work this out for myself as my installer wasnt prepared to.

Anyway hope this helps and good luck!

Cheers
Robin

[Gilbertd]

For some reason larger BMW engines don't achieve the economy on gas that they do on petrol yet other similar sized engines do. In saying that, if your idle is iffy, it may be that the system hasn't been installed or set up correctly, you didn't make a good choice with your installer http://www.lpgforum.co.uk/viewtopic.php?f=27&t=10838 (and others). Before accepting what you have as the norm, it might be worth getting someone independent to have a look at it.

I agree with you totally on the difference in driving dynamics between a petrol engine and a diesel engine. Not only that, when have you ever heard anyone saying how nice a diesel engine, any diesel engine, sounds on full chat? They just don't make the right noises! Personally I'd run a petrol engine on LPG even if it was more expensive to run than a diesel. As far as I'm concerned, my fuel choices are petrol or LPG.

[Tubbs]

I have one customer reporting a solid 29 mpg. And another reckons he is getting a regular 31. Both the 3 litre ones. The second one is doing regular motorway commutes for work on the motorway. But he works in manchester and lives on the M6 corridor. So its a combined figure. He has little spreadsheets and everything, taking the petrol usage into account. I cant say they are a regular conversion, not like the E series ones or the Lexus Rx or L322 range for that matter. You see a lot of them. So i can only really comment on the ones i have done. Which isnt that many.