Discussion
Been running lpg for years. Average cost is around 65p/litre.
Only problem is that there is a shortage at the mo'. About 1/2 the stations in the SE are out. But that will sort itself out when the refinery comes back on stream.
I have done about 60K in my R/R P38 with noo problems. About 14 mpg on lpg = roughly 26 equivalent. Also, you engine oil stays cleaner for longer and you don't need cats at MoT time.
Only problem is that there is a shortage at the mo'. About 1/2 the stations in the SE are out. But that will sort itself out when the refinery comes back on stream.
I have done about 60K in my R/R P38 with noo problems. About 14 mpg on lpg = roughly 26 equivalent. Also, you engine oil stays cleaner for longer and you don't need cats at MoT time.
You won’t get the same MPG because a litre of LPG contains less energy than a litre of petrol - there is no way of getting round that. However it should still work out as a considerable saving over petrol. Expect 10 to 20% less MPG on gas compared to petrol.
Some people say they don’t have any difference, but the only way that’s possible is if the car is also injecting some petrol, is running very, very lean or is a little down on power (or some combination of those). Generally in a big V8 you wouldn’t tend to notice a minor power loss anyway.
On the sort of cars you’re talking about LPG still makes a lot of sense IMO, as long as you’re not buying someone else’s problem.
Some people say they don’t have any difference, but the only way that’s possible is if the car is also injecting some petrol, is running very, very lean or is a little down on power (or some combination of those). Generally in a big V8 you wouldn’t tend to notice a minor power loss anyway.
On the sort of cars you’re talking about LPG still makes a lot of sense IMO, as long as you’re not buying someone else’s problem.
It will largely depends on
How long you plan to keep the car.
How many miles a year you do.
A pre-converted car would be the better option (no guarantee on the standard), but for old cars it would be better to buy on condition over all rather than whether it is already converted. I had my fingers burnt on a diesel S-Type jag - but it wasn't the diesel bits that went wrong.
I am sure SimonYorkshire on here would be able to help, he claims he is an expert on these things, and you appear to be in the group of car users who would benefit from LPG.
How long you plan to keep the car.
How many miles a year you do.
A pre-converted car would be the better option (no guarantee on the standard), but for old cars it would be better to buy on condition over all rather than whether it is already converted. I had my fingers burnt on a diesel S-Type jag - but it wasn't the diesel bits that went wrong.
I am sure SimonYorkshire on here would be able to help, he claims he is an expert on these things, and you appear to be in the group of car users who would benefit from LPG.
charltjr said:
You won’t get the same MPG because a litre of LPG contains less energy than a litre of petrol - there is no way of getting round that. However it should still work out as a considerable saving over petrol. Expect 10 to 20% less MPG on gas compared to petrol.
Some people say they don’t have any difference, but the only way that’s possible is if the car is also injecting some petrol, is running very, very lean or is a little down on power (or some combination of those). Generally in a big V8 you wouldn’t tend to notice a minor power loss anyway.
On the sort of cars you’re talking about LPG still makes a lot of sense IMO, as long as you’re not buying someone else’s problem.
Most LPG installers are pretty clear on their websites that you'll get 80-85% of the economy of petrol when running on LPG and lose about 5% of the top end power. A 20 year old car like an E38 has probably already lost a similar amount anyway and still will have plenty of grunt, so another 4 or 5% won't make much difference.Some people say they don’t have any difference, but the only way that’s possible is if the car is also injecting some petrol, is running very, very lean or is a little down on power (or some combination of those). Generally in a big V8 you wouldn’t tend to notice a minor power loss anyway.
On the sort of cars you’re talking about LPG still makes a lot of sense IMO, as long as you’re not buying someone else’s problem.
These older engines tend to be far more straightforward too and more tolerant of conversions.
Heres Johnny said:
Sparkzz said:
Heres Johnny said:
There are, so I'm told, five reasons why you should never consider an LPG conversion..
Please explain?Posted in general gassing and thread moved to this 'new' sub forum.
Must say, when I saw this thread I had a shiver run through me....oh no, here we go again.
Please, let’s not have another “5 reasons” thread.........
OP, that’s pretty much what I did some years back, had a hankering for a 5.7 Grand Cherokee. Bought a stock car with relatively big miles for its age at a very good price then got it converted. I always knew it would take a while to break even as I do very few miles, and I’m still waiting now, but, overall, I’m happy with the deal. There is a small reduction in VED and come MOT time, it doesn’t get emissions tested if it drives in on gas.
I’ve kept a record of every fuel top up since I got it and have been keeping a record of equivalent mpg. Will post up the figures later.
If the total cost is very important, be pessimistic with your sums. If you just want to drive a big V8 without feeling too much pain at every top-up, why not. Hard to put a value on not feeling ripped off at the pumps.
Please, let’s not have another “5 reasons” thread.........
OP, that’s pretty much what I did some years back, had a hankering for a 5.7 Grand Cherokee. Bought a stock car with relatively big miles for its age at a very good price then got it converted. I always knew it would take a while to break even as I do very few miles, and I’m still waiting now, but, overall, I’m happy with the deal. There is a small reduction in VED and come MOT time, it doesn’t get emissions tested if it drives in on gas.
I’ve kept a record of every fuel top up since I got it and have been keeping a record of equivalent mpg. Will post up the figures later.
If the total cost is very important, be pessimistic with your sums. If you just want to drive a big V8 without feeling too much pain at every top-up, why not. Hard to put a value on not feeling ripped off at the pumps.
So, purely for information, no other purpose. These are facts taken from an example size of 1. The vast majority of my driving is short trips, hardly worth owning car for.
When I collected the Jeep, I drove it 150 miles back from London. I took it steady but did do the limit on the motorway sections of the trip. It returned 22mpg running on petrol. That's about the best one could hope for out of it. I didn't keep records before the conversion, but ISTR it typically did about 15 to 16mpg on our average use.
I've not been able to feel a difference in performance when I've tested it, switching between petrol and gas when driving flat out, although I have no doubt a dyno would tell the tale. This system stays on gas at WOT.
Looking at the data I have collected, on average, it did 13.8mpg actual, 25.2mpg "cost equivalent had it been running on petrol". In percentage terms, that's roughly 56% better than running it on petrol alone, assuming it would do 16mpg on petrol, on average.
And I have included the cost of petrol that has been used for start and warmup as the Prins system starts on petrol then switches over once coolant reaches about 40C. I did used to use a coolant pre-heater in winter to help it switch over sooner as that made a difference on my typically short trips.
It was an expensive conversion, including a valve seat lubrication system, and I'm still a few hundred quid short of breaking even after 15000 miles. If my usage pattern was anywhere near the average, it would have paid back long ago. I knew this was a risk going in, and I'm good with that - I'll get there eventually as I tend to keep my cars a long time. Given interest rates, I don't think I'm losing much had I invested the cash instead.
Again, just my own personal experience, YMMV.
When I collected the Jeep, I drove it 150 miles back from London. I took it steady but did do the limit on the motorway sections of the trip. It returned 22mpg running on petrol. That's about the best one could hope for out of it. I didn't keep records before the conversion, but ISTR it typically did about 15 to 16mpg on our average use.
I've not been able to feel a difference in performance when I've tested it, switching between petrol and gas when driving flat out, although I have no doubt a dyno would tell the tale. This system stays on gas at WOT.
Looking at the data I have collected, on average, it did 13.8mpg actual, 25.2mpg "cost equivalent had it been running on petrol". In percentage terms, that's roughly 56% better than running it on petrol alone, assuming it would do 16mpg on petrol, on average.
And I have included the cost of petrol that has been used for start and warmup as the Prins system starts on petrol then switches over once coolant reaches about 40C. I did used to use a coolant pre-heater in winter to help it switch over sooner as that made a difference on my typically short trips.
It was an expensive conversion, including a valve seat lubrication system, and I'm still a few hundred quid short of breaking even after 15000 miles. If my usage pattern was anywhere near the average, it would have paid back long ago. I knew this was a risk going in, and I'm good with that - I'll get there eventually as I tend to keep my cars a long time. Given interest rates, I don't think I'm losing much had I invested the cash instead.
Again, just my own personal experience, YMMV.
Chris-S said:
So, purely for information, no other purpose. These are facts taken from an example size of 1. The vast majority of my driving is short trips, hardly worth owning car for.
When I collected the Jeep, I drove it 150 miles back from London. I took it steady but did do the limit on the motorway sections of the trip. It returned 22mpg running on petrol. That's about the best one could hope for out of it. I didn't keep records before the conversion, but ISTR it typically did about 15 to 16mpg on our average use.
I've not been able to feel a difference in performance when I've tested it, switching between petrol and gas when driving flat out, although I have no doubt a dyno would tell the tale. This system stays on gas at WOT.
Looking at the data I have collected, on average, it did 13.8mpg actual, 25.2mpg "cost equivalent had it been running on petrol". In percentage terms, that's roughly 56% better than running it on petrol alone, assuming it would do 16mpg on petrol, on average.
And I have included the cost of petrol that has been used for start and warmup as the Prins system starts on petrol then switches over once coolant reaches about 40C. I did used to use a coolant pre-heater in winter to help it switch over sooner as that made a difference on my typically short trips.
It was an expensive conversion, including a valve seat lubrication system, and I'm still a few hundred quid short of breaking even after 15000 miles. If my usage pattern was anywhere near the average, it would have paid back long ago. I knew this was a risk going in, and I'm good with that - I'll get there eventually as I tend to keep my cars a long time. Given interest rates, I don't think I'm losing much had I invested the cash instead.
Again, just my own personal experience, YMMV.
I agree it makes sense, but your percentage is backward When I collected the Jeep, I drove it 150 miles back from London. I took it steady but did do the limit on the motorway sections of the trip. It returned 22mpg running on petrol. That's about the best one could hope for out of it. I didn't keep records before the conversion, but ISTR it typically did about 15 to 16mpg on our average use.
I've not been able to feel a difference in performance when I've tested it, switching between petrol and gas when driving flat out, although I have no doubt a dyno would tell the tale. This system stays on gas at WOT.
Looking at the data I have collected, on average, it did 13.8mpg actual, 25.2mpg "cost equivalent had it been running on petrol". In percentage terms, that's roughly 56% better than running it on petrol alone, assuming it would do 16mpg on petrol, on average.
And I have included the cost of petrol that has been used for start and warmup as the Prins system starts on petrol then switches over once coolant reaches about 40C. I did used to use a coolant pre-heater in winter to help it switch over sooner as that made a difference on my typically short trips.
It was an expensive conversion, including a valve seat lubrication system, and I'm still a few hundred quid short of breaking even after 15000 miles. If my usage pattern was anywhere near the average, it would have paid back long ago. I knew this was a risk going in, and I'm good with that - I'll get there eventually as I tend to keep my cars a long time. Given interest rates, I don't think I'm losing much had I invested the cash instead.
Again, just my own personal experience, YMMV.
you are paying 56% the cost on fuel, so about 44% cost savings on a fill up. if you plan on keeping it for a long time you will reap the benefits though. Sparkzz said:
Evening guys,
I'm currently looking around for an old barge, but I can't justify the cost of fuel running a big V8. I've initially looked for diesels, but the fact of the matter is, some of the old barges such as Jaguar XJ8's or e38 7 series were only made in petrol form.
I've found a couple of garages which aren't too far away from me that appear to sell LPG (Just checked online, not sure how much for)
I was wondering if it would be worth buying a car with the conversion already done. I'm guessing I can expect roughly the same fuel economy but for 80p a litre instead of £1.20?
Anyone running LPG these days?
Firstly I think its best to buy a car that has already been converted. The previous owner has already had the expense. Just make sure all the paperwork is there and it isnt a DIY conversion. You mention 80p a litre for LPG try www.filllpg.co.uk they will have details of local lpg filling stations and also they have details of latest prices.I'm currently looking around for an old barge, but I can't justify the cost of fuel running a big V8. I've initially looked for diesels, but the fact of the matter is, some of the old barges such as Jaguar XJ8's or e38 7 series were only made in petrol form.
I've found a couple of garages which aren't too far away from me that appear to sell LPG (Just checked online, not sure how much for)
I was wondering if it would be worth buying a car with the conversion already done. I'm guessing I can expect roughly the same fuel economy but for 80p a litre instead of £1.20?
Anyone running LPG these days?
I have 2 LPG cars. one I bought with the LPG conversion fitted and the other I have recently had converted to run LPG. I would suggest only having a car converted if, like me you intend to run it for many years/miles.
Treat the LPG system like any other part of the car, ensure it's been maintained well & get it serviced. If it's been installed well they don't require much maintenance. Do a bit of research if you can on the engine and find out how well it handles the conversion as some seem better than others.
I have a Range Rover with the BMW 4.4v8 and it's been faultless for 150k on gas, FIL has supercharged jag engine Range Rover which doesn't seem to take to the conversion as well. Both by the same installer, both well maintained, both using Prins with the jag engine have flash lube but just doesn't run as reliable.
Gas is getting more expensive & harder to find round by me but I've certainly saved a bucket of cash by running on LPG
I have a Range Rover with the BMW 4.4v8 and it's been faultless for 150k on gas, FIL has supercharged jag engine Range Rover which doesn't seem to take to the conversion as well. Both by the same installer, both well maintained, both using Prins with the jag engine have flash lube but just doesn't run as reliable.
Gas is getting more expensive & harder to find round by me but I've certainly saved a bucket of cash by running on LPG
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