Fuel Advice

Converting Your Car to LPG

Making the decision to convert your vehicle to operate on LPG – also called Autogas – can be a difficult one. Following is a range of advice to help you make the right decision for you and your vehicle.

What are the advantages?

  • The average yearly price of LPG per litre is generally 50% the price of ULP, but this varies throughout the year.
  • On most dual fuel conversions, the fuel range of the vehicle is increased, provided petrol and gas tanks are full.

  • Gas burns cleaner than petrol, which in turn keeps the spark plugs and combustion chambers relatively free of carbon deposits.

  • A reduction in engine wear in some areas is normally expected, particularly during cold starting because LPG does not wash lubricating oil from the cylinder wall. However, there can be accelerated wear in the valve seat area in some engines. Oil looks clean longer, but don’t be misled by its condition. Continue to change your oil at normal service schedule intervals.

  • Fuel theft is reduced because LPG is much more difficult to remove from the cylinder than it is to siphon petrol from a tank.

What are the disadvantages?

  • The cost of installation has to be recovered before savings are made.
  • On small cars and certain station wagons, the loss of luggage space due to cylinder size can be quite substantial, with the cylinder encroaching well into the luggage area.
  • Other vehicles sometimes require relocation of the spare wheel due to the cylinder being fitted in the spare wheel carrier area underneath.
  • Most engines suffer a slight loss of performance when converted to LPG. This is mainly due to the compromises needed to use gas in an engine originally designed for petrol.
  • LPG conversions can use up to 30% more fuel, litre for litre, compared to petrol. Incorrect tuning can drastically increase consumption.
  • Specialised technicians are recommended to carry out maintenance on LPG installations, which may increase servicing costs of the LPG system.
  • When running problems become evident in the engine, the vehicle may need attention by a normal service centre and also by an LPG technician.
  • Cylinder inspection and testing is required after ten years. The expiry date is stamped onto the cylinder. This service averages around $500 to $800, which may, or may not include the labour associated with the removal and replacement of the tank. These tests will determine the remaining life expectancy of the cylinder and related pressure control valves.
  • Recent testing indicates LPG fuelled vehicles have no cleaner exhaust emissions than late model petrol fuelled vehicles.

What will it cost me to convert to LPG?

Depending on which style of system is fitted, installation costs average around $2,500 for a basic vapour mixer to $4,500 for a sequential injection system. LPG on average is about 55% the price of Petrol, however you generally use more litres of LPG than petrol. Car maintenance costs may be higher because a licensed installer or repairer must carry out servicing of the LPG equipment.

If you're considering an LPG conversion or purchasing a vehicle that is dedicated to LPG only, click here to calculate the break-even point.

More information

For more advice on LPG conversion, contact RAA’s Technical Advisory Service.

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