LPG Conversion – What to Look for

What to Look for when Getting an LPG Quote

When getting a quote you will be quoted a price and some details but you need to know what is important and also what is being left out.

The spec sheets we have for individual vehicles are a good starting point. These will have the general configuration for your vehicle. There are two types of systems out there. Conventional systems for older cars and injections systems for more modern cards with clever engine management and tight emissions controls.

With the conventional systems there are two types again. American Impco with air-valve system and Italian venturi or ring type systems Of these we will normally prefer to use Impco where possible. The reasons are that LPG converters are more robust and longer lived and the mixer is more complex where as the Venture Style is simper. This is how the two systems are identified at times by calling them a complex mixer or simple mixer.

The simple mixers can be very good if specifically designed for an application, however here in Australia the suppliers have 3 different outside and three different inside diameters and you make up the combination that fits. There is also a type that iis no more than a piece of pipe that has been flattened and it introduces gas into the airstream. Needless to say these simple mixers are not very efficient. Granted they do use a stepper motor that is connected to the card oxygen sensor but only regulates the mixtures after they go through the motor, they have no capacity to control efficiency and maximum air flow and these often can inhibit the cars performance.

Impco mixer are in effect a mixer that works the same as a constant depression carburettor like a Stromberg and are designed to meter exactly the correct amount of gas for the volume of incoming air. Although bulkier to fit and more expensive they are better. with the injection systems there a host of different brands and they all work in a similar fashion and nearly all use the same brand/system of software. That means the choices are about the converter and the injectors. Converters can be affected by contaminants in the gas and they can also have issues in their design that make them more prone to failure. Then there are super cheap copies made in China or Russia. They are just cheap and nasty and people who fit this equipment don’t seem to care about you, your safety or how will it works, they just want your money and then would prefer you disappear.

Similarly with the injectors, most importers have had to change the brand of injectors they use because they had too high a failure rate. That means they have to go out to the market place and find one that isn’t being used by someone else and hope that is ok. Slowly over time the brands and types have sorted themselves and there are definite identifiably better brands out there.

Nearly all systems other than Impco BRC and the cheap imports use an AEB ecu. This should never be fitted under the bonnet as it is sensitive to heat and you will be paying for a new ECU at some stage.

We have replaced numerous ECU’s because they have failed due to over heating and shutting down. Symptoms of overheating are when the lights in the switch go out altogether or all the lights start flashing Next time you start the car they may be visible or even when driving they may return to view.


You need to ensure you are being quoted on the same thing by all, i.e compare ‘apples with apples’.

Injection Systems.

  • Ecu under bonnet
  • Are injectors warranted against contaminant in gas?
  • Parts may need to be serviced maintain warranty
  • Is the software used by the LPG company, unique to to the installer or available Australia wide? This is important because if the installer is not using a reputable brand, how will your equipment get serviced in the future if the LPG company goes out of business?
  • Tanks.  Australian valving means less hassles especially ‘4’ valve tanks. They are cheaper to retest as well.

John Ruskins statement on value:

Its is unwise to pay too much……..but it is worse to pay too little.

When you pay too much, you lose a little money……..that is all.

When you pay too little, you sometimes lose everything because the thing that you bought was incapable of doing what is was bought to do

The common law of business balance prohibits paying a little and getting a lot, it cant be done.

If you deal with the lowest bidder it is well to add something for the risk you run. And if you do that you will have enough to pay for something better.

John Ruskin circa 1890