Hi All

There seems to be a lot of general experience around these parts so here goes with a question or 2 that might make a difference on my next car:

Currently running a VW Scirocco 2.0l turbo petrol. I can get up to about 40mpg if I drive like Miss Daisy or low 30s if in a rush.

Done about 64k miles in the last 3 and abit years and lease ends in Sept.

I am thinking about gettting a diesel or LPG converted car to keep costs down.

Does anyone have any experience of LPG conversions, specifically:

Does MPG change?
What are the risks of having an LPG related engine failure
How hard to sell is an LPG car?

Having done the sums, MPG is not the only determinant of cost for a car (depreciation usually is more, over 3 years). In my mind the market does not like petrol engines now (especially larger ones) so would the depressed market for say a BMW 3 series 330i mean that the £1k or so the conversion would cost and the approx 50% reduction in fuel cost make it a viable alternative to the default 320d?

Thanks for sharing your knowledge!

Al.

If you really want to save money, look at all that you spend – I’m guessing a 4 year lease at 80k on a Scirocco ain’t cheap…

As a large petrol engined car fan (currently 535i) I’ve looked at LPG and tbh didn’t really want to ‘sink’ the conversion cost into the old(er) cars I prefer. So while my car ‘only’ manages 25mpg, the other costs are minimal – little depreciation, ok VED, cheap parts and servicing. And compared to buying a new car, seriously cheaper, and I get to drive in a big, fast comfy car.

Take a look at a few older 5-series cars, esp. FSH ones – they can be remarkably cheap (and reliable).

Don’t do it, I work in the industry and you wont do yourself any favours when it comes to resale time!

I had 2 cars over the last 10 years that I had converted to LPG…It was worth it as LPG was cheap and I was doing lots of miles. I have now bought a Mondeo Diesel however as LPG is relatively more expensive now and I’m doing less miles. Never had any trouble mechanically but you do have to keep topping up your valve saver (another cost) or your engine will lose compression and eventually wont go up hills.

Does MPG change? Yes, anything from 10% to 20% poorer MPG than on petrol (more likely the 20% end). Also lose about 1-2% of power but you won’t notice unless you’re logging lap times at Brands Hatch

Engine failure? Nope

Resale – easy, but you won’t make back the conversion cost as a premium on re-sale, so buy something converted rather than paying for a conversion yourself.

Other pitfalls – availability / range. Depends where you drive and range of the vehicle. In rural areas you might struggle, and in popular, rural areas on bank holiday weekends you’ll definitely struggle as the stations that do sell gas will run out.

Also, depending on type of vehicle, where the tank goes will mean you either lose a lot of your boot to a gas tank, or at best lose your spare wheel (unless you go for a 4×4 with room for it all to be slung underneath).

Also, look for the quality of the system, i.e. multipoint, not single-point.

I had an LPG car (Jeep Cherokee with the tank underneath), was happy with the economics, didn’t replace it with another one – mainly the hassle of hunting down stations with gas was the deterrent for me.

Been running an LPG converted car for 6 months now, and the only drawbacks I can see are relative lack of availability of fuel (not many stations carry it) and in my case, a small tank range. As long as you know where all your local stations are its not too much of a worry, I would advise if possible to get a bigger tank than the 45 litre one in my Mondeo though, as it’s annoying only having an effective range of 220-250 miles when you’ve got used to 600 miles in a diesel.

I bought the car already converted, and would recommend the same. Doesn’t seem to be much desire for LPG converter cars 2nd hand, so any car you convert yourself, you’ll essentially have to write off the cost of the conversion against the fuel saving, the car will not be worth any more come sales time. Kinda struck it lucky with my Mondeo in fairness, as it had 38,500 miles on it and a full service history, so despite being 11 years old it was immaculate save a couple of minor body scrapes, and it only cost me £900!

Oh, and economy on gas is slightly poorer than petrol. Depends on the quality of the conversion mainly, though weight is also a factor. Basically, older single point conversions (like in my Mondeo) are cheap and effective but not as accurate or economical on the fuelling, and your economy on gas can be 15-20% down compared to on petrol, also not helped by the additional weight in the boot of the tank itself. Obviously the fuel is barely more than 50% the cost of petrol though, which makes it significantly cheaper still. A newer conversion will typically be more efficient, though more complex and expensive.

My take on LPG is if you’re happy running an older car, with little value, don’t mind keeping it a few years and are happy to maintain it yourself (or know someone who can do it cheaply for you), then LPG makes a lot of sense. Or if you buy a brand new car, fitted with a factory LPG tank then also it makes sense. If you’re buying nearly new, spending a lot of cash on the car, then converting it, unless you do mega miles it’s probably not worth it in the long run.

As for b r’s take on it above, it makes a lt of sense to run a big engined old Beemer like that, I’ve done it myself, especially seeing as you’ll get a hell of a lot of (reliable) motor for the money. But only if you do very low milage, as otherwise the fuel cost starts to ruin your life!!!

Don’t plan on using the Channel Tunnel either 🙂

When you are doing the sums it muddies the water a little to compare LPG against petrol – becuase if you are running LPG you won’t be using (much) petrol. Thats only worthwhile if you’ve got an existing petrol engined car that you want to keep and convert, or if the car you want is only available as petrol. If you are buying a converted car, or buying with a view to convert, then you want to look at the costs of that LPG car against the most economic version of that car available, not the car you’ll convert. Given that the fuel figures for any given model will usually be a lot better for a diesel, then diesel figures need to be your benchmark

So compare your LPG running costs against those diesel figures not against the petrol model you’d convert. With a lot of cars the difference between LPG/petrol (a poor MPG with cheaper fuel) and diesel figures (a good MPG but with more expensive fuel) isn’t all that impressive, unless you can get the benefit of other LPG related savings – like Congestion Charge freebies if you are cursed with being a londoner

The other consideration is range – generally the gas tanks fitted have to be pretty compact , as well as getting a poorer MPG you’ll be carrying fewer G. There aren’t that many LPG garages around, and although you can also get gas from places other than garages (more cheaply too), compared to a garage forecourt service can be slooooow. Given your milage is fairly high can you afford the time to stop for fuel so often?

Also people take the pi55 asking where the pilot light is etc 😀

Ran a VW 2.1 petrol van for a while on lpg. It was spectacularly thirsty as standard – 21-22 mpg and with lpg dropped a little. The only way I could afford to run it was on lpg all the time though purists say you should run a tank of petrol to evry 4-5 of gas. No engine problems but on a long trip you had to plan your fuel stops or it could be very expensive. There is a website that lists all lpg stations.

Thanks for your thoughts guys

The lease on the Scirocco is £360 a month, it sounds as though the LPG thing is better suited to older cars

I had not really thought of the range issue, work takes me around the NW and Lakes area, so I will check out the LPG garage link

Thanks again for your input

It would seem the answer is maybe?

Al.

I have a 4.4 V8 converted. Been running it for 4 years / 50k miles.
Had a 4.0 V8 petrol converted for 3 years before that.
I dont think I would get another one though.

On a run, it gets about 17-19ish mpg on the lpg. Price wise that very roughly converts to a low to mid 30’s mpg car in terms of running cost. The diesel version gets about 25 to 28mpg. At the time, the LPG was a good bit cheaper and it was the better thing to do and the more powerful option.

Since then though, I’ve found that the LPG is getting harder to get cause of my shifts and my range is limited to about 180miles … which is a pain now.

Next one will be a diesel.

Somebody in work has just sold a duel fuel micra (ie came from the factory like it). Had lots of problems with it, nobody experienced in fixing it. AA said that petrol injectors become troublesome due to lack of use (ie he often had trouble starting it).

He has sold it and bought a small efficient petrol car (because of BiK).

Got a 3.9l V8 Land Rover Defender on LPG.

.It was worth it as LPG was cheap and I was doing lots of miles. I have now bought a Mondeo Diesel however as LPG is relatively more expensive

I converted mine in 1999. LPG has consistently been about half the price of petrol since then.

…but you do have to keep topping up your valve saver…

All modern engines have got hardened valve seats to cope with unleaded petrol. I’ve done about 250000km in my Land Rover and never used any sort of fuel additive.

AA said that petrol injectors become troublesome due to lack of use (ie he often had trouble starting it).

Most systems have some way round this. Typically, they will start on petrol, then switch to LPG at 2000rpm with the throttle shut, ie, your first gear change. Again, no problems in 250000km with a Rover V8.

I ran a Pt cruiser 2.0l on LPG for a 2 years and put 50,000 miles on it with gas. LPG is less dense than petrol so fuel ecomony will be 73% of the petrol fuel economy if it is set up right.

Lack of fuel stations is one drawback the other is the tank. Given the lack of fuel stations especially in East Anglia (you have to go out of your way here) you need a big tank. I had a 90l but becuase it LPG the most you could get into it was 70l giving about 400 miles range in that car. Given the number of miles I was covering that meant filling up twice a week and thats a long time holding that damm button and going out of my way to fill up. Given the size of the tank I needed a spare wheel well tank was ruled out so the tank was mounted in the boot reducing boot space.

If you live near a LPG station or commute on your way past one then LPG makes sense as you can get away with a small tank. If you don’t have one near you then you need a bigger tank. Also LPG eats through spark plugs at least it did on the Cruiser.

Also most systems on modern cars need the petrol tank to be kept and start on petrol.

I sold my Cruiser and bought a 1986 BMW 525e and lived with the mid 30’s mpg from that car instead. I now have 88 530i. No going back to LPG unless it is on an older car and I have the cash to install a sinple single point LPG system which can be started on LPG alone so the petrol system can be ripped out. Also I would need the cash to have the engine rebuilt with a high CR (static about 13:1) to make the most of LPG high octane rating. That would make sense but until then I ust stick with petrol and drive less.

It’s great if you love spending loads of time at filling stations freezing your backside off.

Seriously though, get a diesel.

I read this entire things and there is a lot of knowledge and experience here. I am looking at a 2000 Audi TT already converted to LPG? there is a LPG station on my route to work and I drive about 300 miles a week. It does still have the petrol set up so you can switch back and forth. I like the car and it is available for a decent price ($6k with only 85k miles) so if the LPG doesn’t work out it won’t bother me too much. Sound like a bad idea? i haven’t drove it on LPG yet, only on petrol. Definitely going to drive it on LPG before buying it and have it looked over by a mechanic. I know about gas and diesel engines but nothing about the use of LPG other than what I have read online. Thanks for your time.