Liquefied Petroleum Gas, or LPG , is an alternative fuel that is gaining increasing interest due to its economic and environmental advantages. This type of fuel, also called Autogas , is used as an alternative to gasoline and diesel, offering a considerably lower price and greater efficiency in terms of pollutant emissions. For this reason, many people are considering converting their gasoline car to LPG, but are unaware of the requirements, the process, and the costs involved.
In this article, we will explain in detail everything you need to know about converting a car from petrol to LPG, including the advantages, cost and current regulations. This process may seem a bit complicated, but it has numerous benefits for both your pocket and the environment.
Fuel change
The biggest draw of LPG is its price , which is approximately 50% lower than that of gasoline or diesel. However, despite its advantages, the process of converting a car to LPG is not as simple as it might first appear. Not all cars can be adapted to this type of fuel, and those that can must meet certain requirements.
For example, vehicles converted to LPG must comply with ECE/ONU R-115 regulations . These regulations stipulate that only cars with gasoline engines that meet Euro 3 emissions standards or later are eligible for conversion. These vehicles must have been registered from 2001 onwards, although this rule has some exceptions.
In addition to the regulations, another important point is the type of engine. Indirect injection cars are easier and cheaper to convert than direct injection ones. In models with direct injection, the process is more expensive and involves the installation of specific injectors for the gas, which can cause problems if they are not properly cooled. It is therefore essential to ensure that the vehicle meets all the technical conditions before proceeding with the installation of the LPG kit.
Features to transform a car from gasoline to LPG
Cars converted to LPG are bi-fuel vehicles, meaning they have a single engine that can run on either petrol or LPG. This means that the car will have two tanks, one for petrol and one for LPG, giving it greater range than conventional vehicles.
In the case of indirect injection cars, converting to LPG is much simpler, as it doesn't require complex engine modifications. However, in direct injection models, the process involves additional challenges, such as installing a second set of LPG-specific injectors. These injectors ensure the engine can withstand the high temperatures generated when using this type of fuel. Without this modification, the vehicle could experience engine overheating problems.
Once the conversion is complete, the car can run on either LPG or gasoline. The driver can choose which fuel to use at any given time, allowing them to optimize costs depending on LPG availability or its price at nearby service stations.
However, to obtain the DGT's ECO label , the car must meet certain additional requirements. These include being registered in 2001 or later and meeting Euro 3 emissions standards (for petrol cars) or Euro 6 standards (for diesel vehicles). Diesel cars converted to LPG will not always obtain the ECO label, as the installation is more complex and involves a higher cost.
Process of converting a car from gasoline to LPG
Below we explain the process of converting a petrol car to LPG step by step. The procedure must always be carried out by a specialised and approved workshop.
- LPG tank installation: The gas tank is usually placed in the boot, where the spare wheel is usually located. The size of the tank varies between 35 and 150 litres, depending on the model of the car and the characteristics of the available space. Although a new tank is installed, the petrol tank is not removed, so the car will have two tanks.
- Installing the filling nozzle: At this stage, a filler port is fitted to the LPG tank, usually close to the petrol filler nozzle. If you are travelling in Europe, you may need to purchase adapters, as not all petrol stations abroad have the same filling system.
- Pipe assembly: Pipes are installed so that LPG can flow from the tank to the engine. These pipes must comply with strict safety regulations.
- Installation of the LPG injector ramp: LPG injectors are different from petrol injectors. Because LPG injection generates higher compression in the engine, it is necessary to install additives that reinforce the engine gaskets, especially the cylinder head gasket.
- Installation of sensors and control unit: Various sensors are fitted to monitor the level of LPG in the tank and other parameters. A control unit is also installed to regulate the mixture of petrol and LPG, allowing the vehicle to alternate between these fuels. The car will never run on LPG alone; the usual ratio is 90% LPG and 10% petrol, especially at start-up.
Once the installation is complete, it is necessary to pass the MOT to certify the conversion and ensure that the entire system is working correctly. During this technical inspection, the safety of the gas pipes, valves and tank will also be checked.
Advantages of converting your car to LPG
LPG continues to gain ground in many countries because it offers significant economic and environmental advantages . One of the main reasons for converting is the considerable fuel savings.
- LPG cost: The price of LPG is much lower than that of gasoline or diesel, which can represent a saving of up to 50% in fuel costs.
- Greater autonomy: By having two tanks (one for LPG and one for petrol), the converted cars have a significant autonomy. With both tanks full, an LPG car can exceed 1.000 kilometers without the need to refuel, which is ideal for long trips.
- Lower emissions: LPG vehicles emit up to 40% less of carbon dioxide (CO2) and other polluting gases such as nitrogen oxides (NOx), which is beneficial for the environment.
- ECO label: By converting to LPG, vehicles that comply with Euro 4 or higher regulations obtain the DGT ECO label, which allows access to the Low Emission Zones (ZBE).
Although converting to LPG involves some initial costs, it becomes a cost-effective option in the long run. Car owners who drive more than 30.000 kilometers per year typically recoup their investment within a few years thanks to fuel savings and the tax benefits of the ECO label.
Price to convert a gasoline car to LPG
The price of converting a car to LPG depends on several factors, such as the car model, engine size, and type. Generally, the conversion cost ranges from €1.500 to €2.000 . This price usually includes the conversion kit, labor, and certification. In some cases, the cost can rise to €3.000 for cars with more complex or larger engines.
Furthermore, it's important to note that after the conversion, you'll need to take your car to the ITV (Spanish vehicle inspection station) to have it certified as a bi-fuel vehicle. This certification costs around €8,50 and must be completed within 15 days of installation. Once you've passed the ITV inspection, you can apply for the ECO label at post offices or on the DGT (Spanish Directorate General of Traffic) website.
Regarding the return on investment for the conversion, it is estimated that a driver who travels 30.000 kilometers per year can recoup the investment in less than two years thanks to fuel savings. However, this calculation varies depending on the type of car and how frequently it is used.
LPG prices also fluctuate depending on the location and the gas station. Currently in Spain, the price of LPG is approximately €1,04 per liter , although it can vary slightly depending on the region. In any case, it is still much cheaper than gasoline, which costs around €1,80 per liter.
Limitations and disadvantages
Despite the many advantages that LPG offers, there are also some limitations and disadvantages that need to be taken into account before making the conversion:
- Power loss: Cars converted to LPG typically experience a loss of between 10% and 20% power compared to its usual operation with gasoline. This is because LPG has a lower calorific value than gasoline, which affects engine performance.
- Loss of trunk space: When installing the gas tank in place of the spare wheel, it will be necessary to do without the spare wheel or use a puncture kit.
- Additional maintenance: Although LPG is cleaner than petrol, it requires specific maintenance to avoid problems with the engine valves and ensure proper combustion. In addition, conversions of cars with more powerful or diesel engines can be more expensive and complicated.
Despite these limitations, many drivers find LPG to be a cost-effective and sustainable option. If you drive a lot of miles a year or want to reduce your emissions and reap the benefits of the ECO label, converting to LPG can be an effective alternative.
Conclusion
Converting a petrol car to LPG can be an excellent option both to save on fuel and to reduce CO2 emissions. Although the process is not simple and has certain initial costs, in the long run it can be very profitable, especially if you make intensive use of your vehicle. In addition, obtaining the ECO label brings significant advantages such as access to Low Emission Zones and tax discounts.
The key to a successful conversion is to ensure that your car meets the technical requirements and to choose a specialist garage that can guarantee a safe and quality installation. If you meet these points, converting to LPG is a smart decision that will save you money and allow you to contribute to improving the environment.