LPG conversions for classics

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Twincam16

Original Poster:

27,646 posts

257 months

Sunday 12th June 2005
quotequote all
It occurred to me recently that many Range Rover owners have converted their cars to LPG/dualfuel systems, giving much improved equivalent mpg figures and reducing the running costs without compromising performance.

I wonder whether some traditionally thirsty classics - I'm thinking Jaguar V12s, Jensen Interceptor, Gordon-Keeble GK1, American muscle cars and so on could be made more user-friendly through use of LPG. I know Bristol has been offering it as an option since the '70s without compromising the performance of its cars.

Can thirsty classics be given a new lease of life with LPG, or are some types of engines no-go areas? Anyone know anything - it's just there are some classics I love (Aston Martin V8, for example), but don't really want to own on account of their massive thirst.

2 Smokin Barrels

30,230 posts

234 months

Sunday 12th June 2005
quotequote all
It dosn't really matter. Based upon the average mileage these cars do it wouldn't matter if they ran on Champagne at £160 a gallon.


2SB

PS can you get a duel fuel Nexia?

>> Edited by 2 Smokin Barrels on Sunday 12th June 23:11

Twincam16

Original Poster:

27,646 posts

257 months

Sunday 12th June 2005
quotequote all
2 Smokin Barrels said:
It dosn't really matter. Based upon the average mileage these cars do it wouldn't matter if they ran on Champagne at £160 a gallon.

>> Edited by 2 Smokin Barrels on Sunday 12th June 23:11


That's not the point - if I had a classic GT car I wouldn't want to be doing 10 mpg even if I did only take it out at weekends.

GTs should be for lolloping across continents on a whim. This used to be the preserve of the super-rich. Now the cars have slipped into the range of mere mortals, but the running costs remain the same, petrol being the main problem. This seems to be a good way around it if you really wanted to go Grand Touring

2 Smokin Barrels

30,230 posts

234 months

Sunday 12th June 2005
quotequote all
Petrol is not the main problem. Do the sums. Say most classics do 2,000 miles a year (generous) what's the difference in fuel cost?

PS The Nexia looks good in white.

Twincam16

Original Poster:

27,646 posts

257 months

Sunday 12th June 2005
quotequote all
2 Smokin Barrels said:
Petrol is not the main problem. Do the sums. Say most classics do 2,000 miles a year (generous) what's the difference in fuel cost?

PS The Nexia looks good in white.


I'll wait till the morning when people are being sensible, not merely contrary.

2 Smokin Barrels

30,230 posts

234 months

Sunday 12th June 2005
quotequote all
I'm contrary in the a.m. too! But seriously, the cost of fuel is usually number three in fun car ownership

1) Depreciation
2) Maintenance
3) Fuel

When you've actually owened a car you may understand!!

(PS if the car is a Nexia the depreciation is usually already spent)

agent006

12,029 posts

263 months

Monday 13th June 2005
quotequote all
An LPG conversion has to balance the cost of installation against the savings. The milage you have to do to break even is quite high. If you spend £2000 on converting your car to lpg, you'd need to save £2001 in fuel costs before it became worth it.
Plus the fact that LPG returns worse MPG than petrol, it just costs less.

>> Edited by agent006 on Monday 13th June 00:37

Pigeon

18,535 posts

245 months

Monday 13th June 2005
quotequote all
2 Smokin Barrels said:
But seriously, the cost of fuel is usually number three in fun car ownership

1) Depreciation
2) Maintenance
3) Fuel

Yeah, but we're talking about classics here...

1) Classics don't depreciate.
2) If you're only doing 2k miles a year, maintenance isn't going to be very much at all (apart from the odd bad year if something expensive goes bang) - oil-and-plugs kind of thing.
3) 2k miles at 10mpg = 200 gallons = about 900 quid.

Fuel takes it, I think...

The making-back-the-cost argument isn't conclusive either. For one thing, there's the convenience of not having to spend so much at fill-up time; for another, you can save a whole lot of money by locating the parts on a scrap car and fitting it yourself.

Twincam16

Original Poster:

27,646 posts

257 months

Monday 13th June 2005
quotequote all
I suppose the crux of my question was; are there any kinds of engines (highly-tuned bespoke hi-performance big V8s and V12s for example) that won't run on LPG?

sheepy

3,164 posts

248 months

Monday 13th June 2005
quotequote all
Problem is really the cost of conversion. Pay-back on the cost of converting the car will never occur unless the vehicle is used for high mileage (which most classics aren't)

I looked into converting my XJS to dual-fuel, but really it was going to be a waste of about £2k. Also, with Gordy eyeing up a tax hike for gas, the payback will get worse.

If I had £2k to spare, there's many more interesting things I'd rather do to my Jag than an LPG conversion (XJR engine and supercharger for example)

Sheepy

lanciachris

3,357 posts

240 months

Monday 13th June 2005
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Encountered a jag v12 converted to lpg. owner claimed max 13mpg even on a run, but whether or not it was a dodgy installation I dont know.

Twincam16

Original Poster:

27,646 posts

257 months

Monday 13th June 2005
quotequote all
lanciachris said:
Encountered a jag v12 converted to lpg. owner claimed max 13mpg even on a run, but whether or not it was a dodgy installation I dont know.


LPG won't improve your MPG figures, it's just much cheaper to buy and cleaner too.

aeropilot

34,299 posts

226 months

Monday 13th June 2005
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I'd say wait and see if Ethanol starts to become more widely available, and cheaper than petrol, as in Sweden.
The costs to convert a classic to ethanol should be a lot less (no extra tank required etc) and with an octane rating of 104, it'll be ideal on older high compression engines from the pre-70's era that were designed to run on old 5-star leaded.

danhay

7,422 posts

255 months

Monday 13th June 2005
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Your best bet would be to find a classic that has already had the conversion done.

Youth Gone Wild

4,028 posts

236 months

Monday 13th June 2005
quotequote all
Of course you would probably need to have an unleaded conversion as well, unless you got one of those things that puts some lead substitute into the airflow. Did you read the thing in classic cars about the bloke with his interceptor? He's getting 15mpg, soon to be 20 with a new gearbox.

Twincam16

Original Poster:

27,646 posts

257 months

Monday 13th June 2005
quotequote all
Youth Gone Wild said:
Of course you would probably need to have an unleaded conversion as well, unless you got one of those things that puts some lead substitute into the airflow. Did you read the thing in classic cars about the bloke with his interceptor? He's getting 15mpg, soon to be 20 with a new gearbox.


Yeah, I read that, but I remember an article in Classics about a bloke who'd coonverted his Interceptor to LPG and was getting the monetary equivalent of 30 mpg.

aeropilot

34,299 posts

226 months

Monday 13th June 2005
quotequote all
Twincam16 said:

Youth Gone Wild said:
Of course you would probably need to have an unleaded conversion as well, unless you got one of those things that puts some lead substitute into the airflow. Did you read the thing in classic cars about the bloke with his interceptor? He's getting 15mpg, soon to be 20 with a new gearbox.



Yeah, I read that, but I remember an article in Classics about a bloke who'd coonverted his Interceptor to LPG and was getting the monetary equivalent of 30 mpg.



So if you did 3000 miles per annum in your Intercepter, it would take about 4 years to recoup the money spent on the conversion, then your quids in unless, as is rumoured, within the term of this Govt. Gordon the Nasty drastically hikes up the price of LPG.

Of the 3 people I know that have had cars converted to LPG, 2 have now done away with it.



Twincam16

Original Poster:

27,646 posts

257 months

Monday 13th June 2005
quotequote all
I'm not talking about necessarily commuting in it, I'm just conjecturing that, say if you were to take your car on a very long journey, it might be much cheaper running on LPG. I'm thinking a big cross-continental European run or something (then again, can you get LPG everywhere?)

aeropilot

34,299 posts

226 months

Tuesday 14th June 2005
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Twincam16 said:
(then again, can you get LPG everywhere?)


Exactly

If you end up having to use petrol for more than 50% of the time because of unavailabilty of LPG, especially on a car with high consumption anyway, what's the point of shelling out £2k or more on converting the thing to LPG.

andytk

1,553 posts

265 months

Tuesday 14th June 2005
quotequote all
In terms of engine combo's that won't take LPG there are two main no nos.

The first is any engine that absoloutly must have lead in the fuel to stay running. These are proper bona fida classics and you can still legally buy leaded petrol for them, but it costs a mint and I think you've either got to prove ownership or are limited in the amount you can buy.

Second is turbocharged cars. You can convert these its just that the difficulty in conversion is usually so expensive it makes it pointless. Its especially bad if its a modern efi turbo system that needs mapping.
I asked on the Jap chat forum recently about converting an RX 7 to LPG as these get some seriously crap fuel economy, but are quite cheap to buy a used example. Would have been a good conversion apart from the difficulty of it.

Andy