Graeme Cooper Automotive

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General advice
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Petrol engine tuning
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Although LPG injection gas systems provide the optimum balance between cost and effectiveness where conventional fuels are concerned, its use has largely been superseded by hybrid systems, meaning a combination of electric motors and small petrol engines. This especially applies to taxi and other fleet operations. In new vehicles, even automotive Diesel engines are being superseded by hybrids.

There are several reasons for this but the main one is the cost of maintaining the retail LPG delivery systems. As the use of hybrids increases, the volume of LPG sales declines, so the cost of retail tank inspection and replacement cannot be justified. This is why many servos previously selling auto LPG no longer do so. As tanks fall due for inspection and/or replacement they are removed from service.

There is also the belief the electrical power is more environmentally friendly – a nonsense when the electricity is usually created by coal-fired power stations in the first place.

A real dilemma occurs for a vehicle owner where LPG is already fitted. Perfectly content both with performance and economy, it is increasingly difficult to obtain gas when and where needed. Fortunately, most systems are duel fuel, so switching over to petrol will usually get the vehicle to the nearest filling station.

A bigger potential problem for the owner is the 10-year inspection. The cost of inspection alone can approach $1000 (depending on the location and integrity of the inspector) because the tanks must be inspected internally as well as externally and many have to be removed and replaced to do this. Also, that cost does not include replacing a failed tank and/or valves.

Despite all of this bad news, LPG continues to be a viable choice for many owners especially where change to a Diesel is unaffordable or changing to a hybrid drive is not feasible. When many Km are travelled, the cost of installation and/or inspection can be recovered within a reasonable time. Additionally, LPG has a lower level of noxious Oxides of Nitrogen than petrol. Emissions are lower than petrol or diesel. LP gas engines are up to 50% quieter than diesel and can be as much as 70% cleaner and 30% less noisy than a conventional diesel engine. LPG also provides the benefit of much-reduced engine wear

Most petrol-powered vehicles can be converted effectively to either dual-fuel or dedicated gas operation but for the reasons stated above, dual-fuel arrangements offer considerable advantages.

Due to the decline in demand, Graeme Cooper Automotive no longer install LPG systems but can certainly advise on maintenance issues.


In terms of safety, although all fuels are volatile, LP gas has an excellent safety record. The fuel tank is much stronger than conventional fuel tanks as proved in crash and fire tests. When the engine is switched off or if the fuel pipe is damaged, an electronic shut-off valve operated and such systems are constantly being improved. This illustration shows an LPG tank fitted into the former spare-wheel space.

The LPG filler is conveniently located inside the existing fuel filler cap.

For dual fuel installations, the entire changeover process is automatic. The vehicle starts on petrol and when the the engine temperature reached normal operating level, fuel is switched to LPG automatically, without driver intervention. If the LPG tank becomes empty, the system automatically reverts to petrol.

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