changing to a petrol engin with gas conversion

Discussion in 'Tech/Mech General' started by Wildbill, Jan 3, 2014.

  1. Wildbill

    Wildbill Funster

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    just been speaking to sumeone who could not get a 2.5td engine for his camper but managed to get a petrol engine he has just put it in with a gas conversion would it be worth it and how much would it save on fuel
    and running cost
     
  2. golly

    golly Funster

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    I know its not the same, but I have a 2.5 petrol Subaru outback, I had a gas conversion done a few years ago. On petrol I get about 28mpg, on gas I get about 23mpg but am only paying £0.66p a litre for gas.
     
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  3. Tootles

    Tootles Funster

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    I'm running a Subaru 2.5 Legacy Outback estate on LPG, and I'm getting the same MPG as with petrol...........???

    Maybe your gas setup needs a check??
     
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  4. golly

    golly Funster

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    Or maybe my right foot is a bit heavy when I know Im not paying petrol prices :Rofl1:
     
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  5. sticky130

    sticky130 Read Only Funster

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    I feel such a saddo knowing this but I only know as we also have a converted LPG Jeep.

    LPG has only 80% of the calorific value of petrol so you will always get a slightly lower MPG, but the good bit is it is much cheaper. :thumb:

    Nicky
     
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  6. Tootles

    Tootles Funster

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    Well, this is strange. This is my 3rd LPG vehicle. The first was a Series 2 LandRover, on petrol 18 or 19MPG. on gas, 22mpg.
    The second was a Jeep Cherokee 4ltr. That did more to the gal/ltr then on petrol.
    And the Scuby as I said, is doing the same, if not slightly more. The Jeep and the Scuby were/are both auto. Puzzled.

    However, on all three I have noticed a distinctive loss of power on hills.
     
    Last edited: Jan 3, 2014
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  7. pappajohn

    pappajohn Funster Life Member

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    how do you check your mpg.....wait until it runs out then 'brim' it or judge by the cost per fill if frequent part top up.

    As stated, lpg is 20% less efficient than petrol so cannot return a higher mileage for the same driving style and road conditions.
    My rv consistantly returns 10mpg on petrol and 8mpg on gas using empty to full as a calculator.

    The loss in efficiency is very rarely noticed as a loss of power as the engine is working slightly harder to compensate.
     
    Last edited: Jan 3, 2014
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  8. enery8

    enery8 Funster

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    I had a V8 3.5 litre range rover on LPG and it ran better on LPG than on petrol. Better mpg as well.:BigGrin: I would certainly consider a camper/motorhome on LPG after running my old rangy on it.:thumb:
     
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  9. DavidG58

    DavidG58 Funster

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    if a lot of your journeys are short you must factor in the miles you do on petrol before the LPG switches over. We run a Land Cruiser with LPG conversion, in winter doing about 1 mile to work and 1 mile home we hardly use any LPG, just petrol!!
     
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  10. jaytee74

    jaytee74 Read Only Funster

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    changing to a petrol engine with gas conversion

    in my experience well worth doing no difference in performance no engine wear need never change engine oil as engine runs clean all advantages providing it is set up properly i have converted two 1.9 petrol engine ducato motorhomes and done big milage with them touring europe if i had been running on petrol i could not have afforded it but running on LPG reduced my running costs by 40%. now a word of caution if you use a firm to supply and install a basic single point system its going to cost approx £1000 to £1200. if you buy the system and install yourself the cost would be in the region of £700. to justify that sort of cost you have to do the milage to offset the cost if you are not going to do the miles then it is hardly worth doing. anyway thats my sixpenneth. jt.
     
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  11. tonyidle

    tonyidle Funster

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    Ask your installer to re-programme to start on LPG. The only reason that these systems start on petrol is to ensure that the petrol system is kept fresh (to prevent varnish / stale fuel build up in the injection system). You can do that yourself by running on petrol briefly once the engine is up to temperature.
     
  12. tonyidle

    tonyidle Funster

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    Normally I'd say yes but if the engine option is the 2 litre normally fitted to Fiat / Talbot Express vehicles then no. I have experience of both: I converted my 2 litre petrol Talbot Express to LPG and the financial gain was well worth it BUT it turned an already gutless engine (around 60 - 70 hp on petrol) into something that was no pleasure to drive at all. The van that followed was based on the Fiat 2.5TD which, at 90+ hp IIRC, transformed the experience. Replacing a 2.5td with a 2 litre petrol would reverse the experience. It isn't something I would ever contemplate doing.

    You can normally assume a 50% cost saving by converting to LPG.
     
    Last edited: Jan 4, 2014
  13. pappajohn

    pappajohn Funster Life Member

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    the main reaason for starting on petrol is to ensure the vapouriser is of a proper temperature to fully turn liquid propane to a gas.
    the vapouriser is heated by the engines cooling water

    while it will start on lpg it wont be as efficient as it could be until it has warmed the engine.

    depending on ambient temperature mine takes around 10 minutes on petrol before switching to gas..
     
  14. Terry

    Terry Funster

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    Why are you changing ? thought you had rebuilt your engine ?
    terry
     
  15. Wildbill

    Wildbill Funster

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    yes terry I had and then we hit an object tarring the sump off:cry:
     
  16. Terry

    Terry Funster

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    Is it a 2.5 td engine from a old ducato your after? I can ask my mate to find one if you want ? He found one for a member about 6 mths ago -
    terry
     
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  17. MikeD

    MikeD Funster

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  18. Tootles

    Tootles Funster

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    Quick Bill, JUMP IN!!! :BigGrin:
     
  19. Wildbill

    Wildbill Funster

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  20. tonyidle

    tonyidle Funster

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    Propane boils off at -40 degrees C and therefore requires no additional heat to fully vapourise. The reason for heating the vapouriser (more correctly the converter / regulator) is to prevent water vapour in the atmosphere condensing on its working parts then freezing. "Cold" engine coolant is more than warm enough to do this. Starting on petrol has all the usual disadvantages: increased bore wear, oil dilution (neither of which are anything like the problem they were with carburettor engines), and excessive consumption.
     
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