LPG Conversions – Car Gas Conversion
LPG conversions (car gas conversion) to a car, with an internal combustion engine, is when an Autogas (LPG) fuel system is added by using an LPG gas conversion kit for cars. It can then use either petrol or Autogas.
LPG conversions are done to save money, as the Autogas (LPG) is typically less costly to use than gasoline.
LPG also burns cleaner, emitting less pollutants.
Types of LPG Conversions
There are four types of LPG conversions:
1. Converter-and-mixer systems are the oldest style, dating back decades and still widely used.
The liquid fuel is converted into vapour and then mixed with air before going into the intake manifold.
2. Vapour phase injection (VPI) uses a converter-and-mixer system, but the gas exits the converter under pressure and is injected into the intake manifold.
Electrically controlled injectors improve the metering of fuel to the engine, fuel economy and power, as well as reducing emissions.
This has been the most popular type LPG conversion in recent years.
3. Liquid phase injection (LPI) systems inject liquid directly into the intake manifold, where it vaporises, not using a converter.
The fuel vaporising in the intake manifold cools and increases the density of the intake air, substantially increases power output, improves fuel economy and has lower emission, when compared to VPI systems.
4. Liquid phase direct injection (LPDI) is a direct injection conversion and the most advanced conversion, injecting liquid LPG directly into the combustion chamber.
The LPG instantly vaporises, cooling the combustion chamber fuel-air mixture during the compression stroke, with further performance and emission improvements.
All four are done using an LPG gas conversion kit for cars especially designed for a specific model.
Best LPG Gas Conversion Kit for Cars
The best LPG conversion is arguably the liquid phase direct injection (LPDI) system and the LPG gas conversion kit to match.
LPDI systems are the latest generation in LPG conversions technology.
The LPG gas car conversion price for an LPDI conversion would be at a premium, compared to other systems.
You get a substantial LPG fuel consumption savings (LPG average mileage) with an LPDI , combined with equal or better LPG engine conversion performance, LPG conversion MPG, great drive-ability and lower tailpipe emissions.
It truly is the best LPG gas conversion kit for cars.
Maybe even the “Automotive Holy Grail”.
Liquid Phase Injection (LPI) Systems – Liquid Injection
This car gas conversion system pumps Autogas (LPG) at high pressure from the LPG tank to the engine inlet manifold via a set of liquid LPG injectors.
The injectors spray the liquid LPG into the intake manifold.
The Autogas (LPG) immediately vapourises after being injected. This vapourisation process rapidly cools the surrounding air.
This cooling effect increases the density of the air-fuel mixture, ensuring power and torque are maintained and fewer CO2 emissions.
The effect is similar to intercooling on turbocharged cars.
An Electronic Control Unit (ECU) controls the various components of the liquid injection LPG conversion, including the injectors.
LPG injection signal optimises the flow and LPG injection timing. The ECU is calibrated to the specific LPG conversion vehicle and engine.
This is unlike conventional vapour systems.
Conventional LPG conversions put the LPG through a device called a vapouriser before introducing it into the intake manifold.
This Autogas (LPG) vapour then goes into the intake manifold through either a mixer or an injector.
The result is a less dense air-fuel mixture, which means lower engine efficiency and output.
An old style vapour system can actually restrict vehicle performance, in comparison to liquid LPG conversion.
Direct Injection LPG Conversion
Liquid phase direct injection (LPDI) is a direct injection LPG conversion and is the most advanced, injecting liquid LPG directly into the combustion chamber.
The Autogas (LPG) instantly vaporises, cooling the combustion chamber fuel-air mixture during the compression stroke, with further performance and emission improvements.
The best car gas conversion system is arguably the liquid phase direct injection (LPDI) – direct injection LPG conversion.
LPDI systems are the latest generation in LPG gas conversion technology.
You get a substantial fuel savings with an LPDI, combined with equal or better engine performance, great drive-ability and lower tailpipe emissions.
Converting to Liquid LPG is a true Win-Win option.
Performance
A vehicle with a state-of-the-art liquid LPG conversion produces at least the same amount of power when running on Autogas (LPG), as compared with running on petrol.
The dynamometer graph below shows the car gas conversion versus petrol performance comparison of a Holden Commodore VE 6.0L.
The liquid LPG conversions produce more power and torque than when running on petrol.
Car Gas Conversion Reliability
Direct injection LPG conversion is so reliable that more than 1 million of them have been factory fitted by automobile manufacturers around the world.
Both Ford and HSV have chosen liquid LPG for their factory equipped Autogas (LPG) vehicles.
The manufacturers of these systems are so confident that they offer extended warranties on the liquid LPG systems.
Saving Money and the Environment
One of the biggest advantages of LPG conversions is the savings realised on fuel costs.
Car gas conversion will generally deliver a cost saving of between 50 to 65 cents per litre.
It is the safe, inexpensive way to run your car.
Especially as the family budget seems to get more and more stretched!
This results in hundreds, if not thousands of dollars of savings every year depending on your vehicle usage.
Running an engine on Autogas (LPG) may also reduce maintenance costs.
Autogas (LPG) is a cleaner burning fuel than petrol, so engine life is not affected.
Environmental savings are also part of the equation.
It creates appreciably less carbon dioxide (CO2) than unleaded petrol.
CO2 is the primary greenhouse gas causing long term climate change.
Overall tailpipe emissions can be up to 15% cleaner than petrol.
LPG Gas Conversion Kit for Cars: Price & Availability
The LPG conversion kit for cars price varies based on the conversion type, with LPG converter-and-mixer conversion systems kits for cars being the lowest price range whilst LPG liquid phase direct injection (LPDI) conversion kits for cars would be the highest price range.
You can easily get online quotes or find online prices.
There are over 100 engineered liquid LPG conversion kits available for domestic and imported cars available from a number of Australian suppliers.
There are also many specialist installers around the country who can install these LPG conversion kits on your car.
Maybe it’s time for you to consider getting the car gas conversion “Automotive Holy Grail”?
Eric Hahn has over a decade of experience in the LPG industry and has become a key figure in shaping how LPG is marketed and communicated. As the creator of one of the world’s first LPG blogs, Eric has authored over 200 technical posts, helping educate and inform the industry and consumers.
Eric has served on multiple committees for Gas Energy Australia and the World LPG Association (WLPGA), contributing to important discussions and advancements within the global LPG sector. He has presented at WLPGA Annual Conferences, sharing his expertise as a speaker, panellist, and panel chair.
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Steve Reynolds
Technical Consultant
Steve Reynolds is a leading expert in the LPG industry with over 22 years of experience. As part of the national management team at ELGAS, Steve ensures the safe and efficient storage, handling, and transportation of LPG. He serves as the lead investigator for incidents and collaborates with authorities on industry developments.
Steve is a technical advisor to Standards Australia and Gas Energy Australia (GEA), and an active member of the World LPG Association (WLPGA), contributing to global standards and technical reviews. He holds a BSc. (Hons) in Industrial Chemistry from UNSW and has held senior safety and technical roles at ELGAS, making him a trusted authority in LPG safety and standards.