Ask an expert

I am considering converting my vehicle to run on LPG.

All of the conversion centres charge seemingly high prices to carry out the conversion.

Can I purchase a DIY kit and install it myself then get an LPG mechanic/engineer to certify this work?

I don't understand why the cost of conversion is so high when the parts are relatively cheap and uncomplicated (basic mixer type).

Thanks,

Richard

From the "Ask Jack" archives - 27 March 2009

You have raised some interesting questions and in an effort to give you the best answer possible I have called on the expertise from the people at Rockgas. They certainly have the passion for this particular fuel.

Yes, LPG equipment can be installed by a non qualified person provided it is checked and certified by an approved LPG certifier. To help save time and money it is strongly recommended that the certifier carries out agreed checks during the installation rather than wait until you have completed the conversion. Finding a certifier willing to do this may be more difficult than it seems before you even think about the actual costs of such a service.

Be very careful purchasing second hand equipment. It must be approved for use in NZ and as regulations have changed over the years, there will be older equipment offered for sale which no longer meets the required standards.

Listed below is some general information on LPG;

It is an ideal automotive fuel that is less harmful to the environment than petrol and diesel, providing that the LPG equipment is suitable for the vehicle and has been correctly installed.

Both LPG and diesel both produce significantly reduced amounts of greenhouse gases than petrol, approximately 10 to 20 per cent less.

LPG produces 20 per cent fewer nitrous oxides and other ozone-forming gases and up to 80 per cent less emissions of air toxics like benzene and formaldehyde than petrol or diesel.

LPG contains far less particulate matter than diesel.

LPG has historically been cheaper than petrol, particularly if purchased using a Rockgas Fuelcard. At present the price advantage LPG offers is 17 cents per litre for low volume users through to 21.4 cents per litre for Taxis assuming the Rockgas Fuelcard is used for these purchases.

The savings are calculated based on the current Wellington pump price for 91 grade petrol, which is $1.589, and the current Rockgas Fuelcard price for low volume users or Taxi operators in Wellington.

Importantly these calculations assume that 30% more LPG than petrol will be used over a given distance. Going forward it is almost impossible to predict energy prices however, it is likely that LPG will continue to offer savings because there are a number of gas fields being developed internationally (including the Kupe field in New Zealand) which may help to keep LPG prices lower than oil prices.

Unless purchasing a new vehicle where LPG can be specified as the fuel type at no extra cost, such as the Ford Falcon XT, there is a significant cost involved in converting a vehicle. Savings therefore will only be experienced by those who will use LPG for most, or all, of a vehicles working life and where the distance travelled by the vehicle is reasonably high. This makes LPG an ideal fuel for taxis and other high mileage fleet operators.

LPG technology, as with vehicles generally, has evolved significantly over the past twenty years. It is important that the type of LPG equipment being fitted to a vehicle is appropriate for the vehicle and will compliment, rather than interfere, with the vehicles original equipment. This is particularly important for the vehicles electronic and induction systems.

In summary second hand equipment should be restricted to LPG tanks, which are required to be retested every ten years, and for which new parts can be obtained to replace any worn parts, such as valves.

For further information go visit the Rock Gas webstie (www.rockgas.co.nz/