LPG running costs

[Gad-Westy]

I need to replace my BMW 330. It's just costing too much in fuel to the point where even for longer journeys it is sometimes left at home in preference to the Smart. This totally defeats the point of why it was bought in the first place.

Anyway, the upshot is that I would like to replace it with something more economical. Inevitably I'm looking down the diesel route but I'm curious to look down the LPG route as well.

Assuming I was buying a pre-converted car, how do the like for like fuel costs stack up (I realise I need to factor in additional servicing too)?

Using my current car as an example:

It does 26 mpg. If petrol is 133.9/l, 1000 miles would cost me £262

LPG is around 75p per litre at the moment but I don't know what mpg the same car would do running lpg if anybody could take a stab for me.

If I had a 330d Those figures would probably be more like:

37 mpg. Diesel cost, 137.9, 1000 miles would cost £169

Just after some rough figures for comparison.

[tomsugden]

Why don't you convert the 330 to LPG?

I run a P38 on LPG. I reckon LPG is about 10% less efficient than petrol, but the cost of it more than makes that up. £40 fills it up, and I get about 150 town miles, or up to 330 motorway miles. Not too bad for a 4.0 V8.

[Monkeylegend]

You need to top your gas tank up to the brim, drive 50 miles and refill, then calculate your usage.No other method is acceptable. Best done before you buy the car.

[weyland yutani]

Monkeylegend said:

You need to top your gas tank up to the brim, drive 50 miles and refill, then calculate your usage.No other method is acceptable. Best done before you buy the car.

LPG is a real money saver for me, mileage is a little less but half the cost of petrol and performance
is identical. Sure beats driving a diesel!

[Gad-Westy]

tomsugden said:

Why don't you convert the 330 to LPG?

I run a P38 on LPG. I reckon LPG is about 10% less efficient than petrol, but the cost of it more than makes that up. £40 fills it up, and I get about 150 town miles, or up to 330 motorway miles. Not too bad for a 4.0 V8.

I don't think it would be worth it in the short/medium term. A conversion is what £2000? The car is getting a little long in the tooth anyway and my mileage is probably less than 10,000 per year.

[edward1]

I have just booked my jag in for a conversion, having done quite a bit of research in the area. The general conclusions are that with a modern sequential injection system the perfromance should not be affected, the MPG a touch less than petrol but then around here gas costs 72.9p/l and petrol 133.9p/l so roughly speaking in cash equivilent terms, if you get 25mpg from petrol then on gas you will be around 45 equivilent mpg.

For me it will mean that instead of 20mpg from the jag I should be looking at the equivilent of 35-40 and keep my supercharged V8

[sklar]

Monkeylegend said:

You need to top your gas tank up to the brim, drive 50 miles and refill, then calculate your usage.No other method is acceptable. Best done before you buy the car.

This is worth a

[Silver940]

I converted my 120k mile Golf about 4 years ago, just coming up 200k miles. Still runs fine. I don't notice the drop in performance and reckon on about 28mpg typically on gas.

I considered buying a PD golf and swapping my parts over but looking at prices and the milage I did it was going to cost a whole heap more than the conversion cost. Made sense. Only thing is that the car becomes to cheap too run to justify changing it! Hence it's mileage now...

[andrewrob]

This would be worth a read
http://www.reallymeansounds.com/forum/car-chat/500...

ETA £2000 seems a bit too high. A friend had an E46 328 converted recently for £1500. £2000 would be more like a V8/supercharged V8 setup.

Edited by andrewrob on Wednesday 8th June 10:47

[Gad-Westy]

weyland yutani said:

Monkeylegend said:

You need to top your gas tank up to the brim, drive 50 miles and refill, then calculate your usage.No other method is acceptable. Best done before you buy the car.

LPG is a real money saver for me, mileage is a little less but half the cost of petrol and performance
is identical. Sure beats driving a diesel!

Sounds good to me. I really cannot get excited about buying a diesel.

So based on 10% worse economy and based purely on fuel usage:

LPG: 23 mpg, 75.9p/l, 1000 miles costs £150.

Doesn't sound too bad to me.

[Gad-Westy]

sklar said:

Monkeylegend said:

You need to top your gas tank up to the brim, drive 50 miles and refill, then calculate your usage.No other method is acceptable. Best done before you buy the car.

This is worth a

I feel I may need a whoosh parrot. What am I missing?

[tomsugden]

Someone on here was looking to buy an LPG car. He contacted the owner saying he wanted to test the lpg consumption using the above method. Owner told him to do one.

[Gad-Westy]

tomsugden said:

Someone on here was looking to buy an LPG car. He contacted the owner saying he wanted to test the lpg consumption using the above method. Owner told him to do one.

Ahh, I see. I suspect that may have been my answer too!

[Gad-Westy]

In terms of servicing, what additional work is required? Can any old garage carry it out or are we talking LPG specialists?

[tomsugden]

Specialist for the LPG system. Needs a service once a year if you're doing average mileage. Last one cost me about £100 to change the filter, check everything over etc

[Monkeylegend]

Gad-Westy said:

sklar said:

Monkeylegend said:

You need to top your gas tank up to the brim, drive 50 miles and refill, then calculate your usage.No other method is acceptable. Best done before you buy the car.

This is worth a

I feel I may need a whoosh parrot. What am I missing?

I am too technically inept to do a link but I am sure somebody else cleverer than me will do one for you, its worth a read. Search for LPG fuel consumption, you might find it.

[Silver940]

Or you can buy the filter online for about 16quid and fit it yourself. They don't do much more than that on the service.

[tomsugden]

To be fair they checked the diagnostics on mine, and put a new map on it, which improved the consumption a bit

[Dino D]

I converted my 02 330i e46.
On petrol I got 25mpg (OBC readout) and lpg I got 21mpg (tank to tank check). Most people get more than 25mpg from a 330i but I drove it hard, especially since the LPG was fitted as it was costing me as much 320d and cheaper than a 330d to do drive!
It went slightly better on 98 petrol than on lpg (the 330 only delivers the full 231bhp on 98octane) but it still hit the limiter in 5th on LPG...

My only grip was that I fitted a 45 'donut' tank in the spare wheel well and it took 40l of LPG which meant fill ups every 170 miles if I remember correctly. If I did it again I would go for a bigger tank to mean less frequent fuels stops. I put up with it as I really wanted run an i and not a d but was doing mega miles at the time so LPG was the only option.

A good conversion will cost 2k so you need to see if you are going to be keeping the car and doing the miles to recoup your cost...

[horster]

I recently had my Lexus RX300 converted to LPG. Using a BRC kit it cost £1750 fully fitted and with a life time warranty on the installation and parts also. No noticable drop in performance. Had it about 5 weeks now. Also near me gas is 65 pence per litre and I can get 250 miles on a tank which costs £40 quid to fill. Best thing I did tbh. Only downside I can think of is that you want to kee the car for as long as possible to maximise your return.