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Author: Subject: When Does LPG become 'worth it'?
morcus

posted on 4/8/12 at 08:01 AM Reply With Quote
When Does LPG become 'worth it'?

I spoke to my Dad this morning and he's not really happy with his Datsun oldman, or Nissan Note to give it his propper name, and wants another big car and asked if I knew anything about LPG, which I don't really. From what I've heard it costs about 90p a litre, you get less power from it but you get a simillar MPG to petrol and the conversion costs somewhere between £1k-£2k, though he'd want to buy something that had already been done.

He was meant to be getting a Mustang last time he swapped cars, but having a baby meant that was put off for another 16 years to about 2023 so he want's something that would fill that place like another Jag or a BMW, he currently does about 20 miles a day so I'm guessing he would be at the point that it would be worth doing?

I know alot of people on here have experience with the stuff so just wanted to know what it's like to actually live with and I'll report back to him.





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plentywahalla

posted on 4/8/12 at 08:25 AM Reply With Quote
I ran a Range Rover with LPG conversion. It is definately cheaper to buy but disadvantages are many:

It is only 75/80% as efficient as petrol so multiply price by 1.25 or 1.3 to compare.
The tank capacity is usually much smaller than petrol tank so you fill up more often.
Filling stations are rare in the countryside so you drive further to find them.
The engine has to start on petrol then switch over so you still need petrol.
Pump prices vary widely and in certain areas where there are few stations prices are sky high.

In my experience living in a rural location I found I had to buy almost as much petrol as gas, and with the extra running around I decided I didn't really save anything. I know others who claim differently.

Whatever you do get one that has been professionally installed and is certified. Avoid DIY jobs!





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jossey

posted on 4/8/12 at 08:37 AM Reply With Quote
To be honest if you can get a second hand kit and for it then it will pay for its self pretty quick it can half the fuel costs if you get a cheap kit for let's say £300 and you spend £100 a month on fuel then you draw even at 8 months obviously getting a fully fitted kit for 2k will take a hell of a long time to be worth it.

I calculated all my options and ended up getting biodiesel instead. So I buy bio at 85p - £1.00 a litre which runs fine in my car I just change the fuel filter once every few months.

You can use 2500 litres tax free. You can make your own bio for about 70p per litre from new veg oil and 13p from old oil.

The good thing about this stuff is it doesn't need any conversion on most cars and it reduces your carbon footprint to almost 0.

I can do around 27000 on 2500 at 8p per litre if I buy in bulk (1000ltr)
Total £2125. @ 49mpg average

Normal fuel costs 137.9 average
27000 x £137.9 = £3723

Saving = 1598 - £30 in fuel filters £1568

If I got offered a lpg car cheap I would have gone that route but I couldn't justify the conversion costs

[Edited on 4/8/12 by jossey]





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morcus

posted on 4/8/12 at 08:42 AM Reply With Quote
Thanks for the replies, but I don't think he'd go the Bio fuel root, I'll pass on the info all the same though.





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ianclark1275

posted on 4/8/12 at 09:02 AM Reply With Quote
My camper is LPG and the "worth it" question is not easy to see as per prev posts

Best comparison is "pence per mile"

LPG has nearly doubled in price over the last 4 years so cost per mile goes up

I burn 1 litre of gas every 2 miles. Lol

So 64p litre is 32p per mile, which for a 6.0L is not too bad

Things I've found:

Get it set up on a mot gas analyser using HC values
As they can be running rich and wasting fuel

You will struggle to start engine from cold on gas you need petrol but only for 30 sec then switch over

Get biggest capacity tanks you can (ive 2x60L)





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zilspeed

posted on 4/8/12 at 09:14 AM Reply With Quote
Range is the killer.

When I had my Golf Cab, I converted it to LPG.
This used an Aldesa sequential kit.
Because I did it myself, payback was around a year based on my all up £600 installation cost.


Range using a spare wheel well tank was at best 220miles.
That doesn't actually mean you'll feel confident to do 220 miles though.
After 150 miles you start looking for gas.

At that time, my nearest reasonably priced LPG station was 17 miles away, but I worked there.

When we went on holiday to cornwall in that car, I was forced to plan my fuel stops beforehand based on range and fuel availability. That's a hassle. Not insurmountable, but more grief than many people actually can do with.

If you don't do a huge amount of miles, you could probably put up with the reduced range.
Having said that, if you do less miles than fuel cost maybe doesn't matter so much.

I've had a few cars since.

Now run a Passat 2.0 TDI which had about 50 more bhp and does 55mpg easily.

The running costs of both cars are similar, but one had about 90bhp and demanded a degree of planning relating to fuelling. The other has an extra 50bhp and can be fuelled up anywhere.

I enjoyed the experiment but am now in no doubt as to the innate good sense of a modern diesel in comparison.

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britishtrident

posted on 4/8/12 at 09:46 AM Reply With Quote
LPG becomes worth it only on cars that do about 33mpg or less, it would make no sense on a Nissan Note.
LPG cost around the country varies much more than petrol prices.
MPG on LPG is 10 to 15% worse than on petrol
Tank size should be based on how much fuel you use in a week, I find a 60 litre tank suits my needs perfectly but a 40 litre tank will suit average use in a small Nissan
The switch over to LPG should be set to about 32c (ie after about 0.5 miles running) switching at a lower temperature will lead to cutting out due to freezing and shorten the life of the gas injectors. in any event it is impossible to start on petrol when the temperature is below or close to 0c
Because of starting on petrol add £3 to weekly LPG cost.

The latest systems such as Stag-300 Premium are connected to the cars EOBD diagnostic socket and will not only do initial calibration it can also self-tune on the road and continue to refine the gas injection times when in daily use.





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morcus

posted on 4/8/12 at 05:31 PM Reply With Quote
He doesn't want to LPG the note, he hates the thing and wants to swap it for something with an engine at least twice the size, which is why he's look into LPG.





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mark chandler

posted on 4/8/12 at 06:12 PM Reply With Quote
Couple of P38 range rovers that I covered in excess of 200,000 miles in, save a lot of money

Last car I ran was an XK8 on LPG, this was a Vogas sequential kit which I selected as it allows you to blend fuel with the gas which lubricates the valves and you can configure based upon load so when you floor it the car runs just on petrol.

The car had 65,000 miles when fitted, sold with 145,000 miles still running well, in that time I had to replace the vaporizer diapham once.

I used a second hand toridial tank which replaced the spare wheel (90 litres) this gave a range of ~300 miles, car gave the equivilent of 50mpg compared to petrol (It did spend 95% of its time on motorways).

You just need to plan your journeys around LPG stations when running low, it literally halved my running costs with no discernable loss of performance (no more than having a passenger all the time)

For a while I used to get 47kg gas cylinders delivered to my house and pumped across, a bit boring but more savings to be made and removes the LPG station dependancy.

Make sure you get a decent sized filler hose, 1/2" flexible not a 8mm copper pipe !

Regards Mark

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Oddified

posted on 4/8/12 at 06:28 PM Reply With Quote
My motorhome used to have a 2.5L td engine, not very quick and only low 20's mpg. I then fitted a 3.9 rover v8 and lpg, and that was the best thing i ever did. Effortless cruising at any 'sensible' speed and far cheaper to run. Yes there aren't as many lpg filling stations, but once you've been using it a while you soon learn where there are and it's not a problem. Worst case scenario is you run out and have to run a few miles on petrol, not a big deal.

I think if you have a big vehicle/engine and do a fair few miles each year, lpg is well worth fitting. If on the other hand you have a modern small tin top which does good mpg any way and you don't do many miles, then don't bother.

Ian

[Edited on 4/8/12 by Oddified]

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scootz

posted on 4/8/12 at 07:58 PM Reply With Quote
Have the LPG Direct-Liquid-Injection systems come on any?

I still think that a toy-car that's set up to run exclusively on Liguid-Injected autogas would be a stormer! Imagine your car mapped properly to run 110RON fuel!





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Ninehigh

posted on 4/8/12 at 10:21 PM Reply With Quote
Try this out






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ChrisW

posted on 5/8/12 at 10:45 AM Reply With Quote
quote:
Originally posted by scootz
Have the LPG Direct-Liquid-Injection systems come on any?

I still think that a toy-car that's set up to run exclusively on Liguid-Injected autogas would be a stormer! Imagine your car mapped properly to run 110RON fuel!


That's a project I'd like to do too, if only I had more time and less other things in the queue wanting money spent on them.

I'm intrigued to hear about running it on the 47kg cylinders. I knew it was cheaper to fill them from the big central heating cylinders you get in rural places with no gas, but I'd assumed that with delivery on top the rental cylinders would work out more.

However, for ultimate cheap running, CNG has to be the way, right?

Chris





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Strontium Dog

posted on 5/8/12 at 11:12 AM Reply With Quote
I have a GT4 running around 300hp. I have a LPG kit on it and it is great and costs less to run on fuel than my Golf. And as to losing power on gas, I don't think so! In fact if my gas kit was up to flowing enough gas I could get more power than when on petrol as the det disapears and I could wind the boost up and advance the ignition timing to make more power. The only problem I have (being a cheapskate lowcoster) is I took a kit off of an Integrali and it runs out of gas at about 200hp. Up until then it is spot on and is more than adequate for daily driving and if I need to blow a scooby away I just touch the button and we're on petrol again and 300hp. I would need to change the regulator/vaporiser and fit bigger or secondary gas injectors if I was to run it at full power but then it would go to full power on gas. Whats not to like about LPG?



[Edited on 5/8/12 by Strontium Dog]





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The Shootist

posted on 7/8/12 at 08:03 PM Reply With Quote
One big reason for LPG...

One big reason for LPG...it's about 108 Octane!

I've seen some big muscle cars over here that run LPG for the sole reason that the Octane allows them to run a really built engine without Octane booster and fear of detonation.

One of these seen years ago was a blown Chevy Small Block thumping out 600hp, and daily driven.

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morcus

posted on 8/8/12 at 01:04 AM Reply With Quote
I'll pass that on to him, he's looking at a V8 chrysler at the moment, on a side note, does it effect your tax class as it must change your emissions.





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cliftyhanger

posted on 8/8/12 at 06:53 AM Reply With Quote
We run a factory-converted LPG Zafira.
Chosen as the purchase cost (at 2 years old) was significantly cheaper than an oil-burner version, and the oil-burners had a poor reputation. (ir we paid 8K, diesel zaffy would have been 10k, and a friend bought a Touran for 12k which has cost him a fortune to maintain as it keeps going wrong. He has recently traded it in)

Ours has just been thrashed through France giving approx 30mpg, probably a few mpg less (10% ?) than petrol. We pay locally 75p/litre so on that basis that works out 11 1/2p per mile.
Put that in perspective, a diesel would have to be doing about 54mpg, and that ain't gonna happen in a people carrier at those speeds ( I know the galaxy with 1.9tdi does about 36mpg under those conditions, but is a bit bigger)

Power loss isn't noticeable, and being a factory fit the thing switches between petrol and gas automatically. Emissions are always very low at MoT time, oil stays cleaner longer and so on.
As to Tax it is a tenner a year cheaper I think than a petrol version. Not much difference at all.

The fuelling up is a bit of a PITA, but our local petrol place sells it, and on when away the sat nav has the LPG stations as POI's so we can find then when needed. But at worst you have to run petrol, but that always winds me up as it costs so much more!

Would I have one again? possibly. But only if I can buy the stuff locally and easily.

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ianclark1275

posted on 11/8/12 at 08:09 AM Reply With Quote
Agree with last post....

You do get used to where the LPG stations are

I drive from york to Belgium and holland every year in camper and have never needed petrol

York bilborough top A64
Pontefract A1
Cambridge servicesM11
Stansted services
Medway services

Then plenty in Europe, but now not much cheaper, except some in Belgium which were 45cents a ltr July 2012
Used to be 18cents a litre !

IC





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britishtrident

posted on 11/8/12 at 09:03 AM Reply With Quote
There is a power loss for two main reason Propane has a lower calorific value than petrol and because the fuel enters the engine as a gas some of the intake air is displaced. As a rule of thumb with a modern gaseous multi-point injection system you get the performance is the same as if you had an engine an engine one size down eg a 2litre would give the same performance as a 1.8

In addition old fashioned induction LPG kits which use an adaptor between the carb or throttle body and the manifold which restricts the volume of air the engine can draw in.





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skydivepaul

posted on 13/8/12 at 09:04 PM Reply With Quote
quote:
Originally posted by mark chandler
Couple of P38 range rovers that I covered in excess of 200,000 miles in, save a lot of money

Last car I ran was an XK8 on LPG, this was a Vogas sequential kit which I selected as it allows you to blend fuel with the gas which lubricates the valves and you can configure based upon load so when you floor it the car runs just on petrol.

The car had 65,000 miles when fitted, sold with 145,000 miles still running well, in that time I had to replace the vaporizer diapham once.

I used a second hand toridial tank which replaced the spare wheel (90 litres) this gave a range of ~300 miles, car gave the equivilent of 50mpg compared to petrol (It did spend 95% of its time on motorways).

You just need to plan your journeys around LPG stations when running low, it literally halved my running costs with no discernable loss of performance (no more than having a passenger all the time)

For a while I used to get 47kg gas cylinders delivered to my house and pumped across, a bit boring but more savings to be made and removes the LPG station dependancy.

Make sure you get a decent sized filler hose, 1/2" flexible not a 8mm copper pipe !

Regards Mark


perfect info for me thanks.
I am considering an xk8 but the mpg puts me off. I was looking at an LPG system for one to enable me to justify fuel costs.
better start looking on pistonheads for one





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