Types Of Car Fuel
What's In A Name?
Most of the time, you don't need to know much about the fuel your car uses.
Petrol or diesel?
That's all you need to remember (although you would be surprised how many people get this wrong every year...)
However, there is a bit more to it than that and even petrol comes in different types. Here's a little more information.
Petrol
Premium Unleaded (95 RON)
This is bog-standard unleaded petrol. Despite the name 'premium', it's actually the standard petrol sold all over Europe.
95 RON refers to the octane level of the petrol. This is a measure of its resistance to explosion, which is a good thing in petrol engines. Higher octane levels are required for some (a few) high performance engines.
Premium unleaded is suitable for almost all petrol engines. You should be safe to use it unless your car's user manual specifically specifies that you should only use petrol with an octane rating higher than 95. Very few cars require this.
Premium unleaded fuel pumps are usually green. Check the label before you fill.
Super Unleaded (98 RON)
Super unleaded is the highest octane petrol that is widely available in the UK and elsewhere in Europe. It can be used in any petrol engine but will only benefit a small proportion as most engines are not able to take advantage of the higher octane rating.
Other Premium Petrols - e.g. Shell V-Power, BP Ultimate
Several fuel manufacturers offer own-branded high performance fuels that claim to offer better fuel economy. This is usually done by including additional cleaning products that help keep your engine's fuel injectors clean, thus making it slightly more efficient and sometimes marginally improving its performance.
These claims are true but the extra cost of the fuel doesn't always make it worthwhile - your car will probably run well and still give good fuel economy on cheaper premium unleaded petrol.
Diesel
Many garages only offer one type of diesel for cars. It may be labelled as 'city diesel' or 'low sulphur diesel', just plain 'diesel' or something else.
Whatever it's called, it should be fine for any current diesel car or van.
Diesel fuel pumps are usually black. Check the label before you fill.
As with petrol, however, there are a few higher performance diesel fuels available. These include BP Ultimate Diesel and Shell Diesel Extra.
Whether these are worthwhile is down to your testing and your vehicle. As with premium petrol fuels, they claim to include more advanced cleaning detergents that will keep your fuel system in top-top condition, improving performance and fuel economy.
LPG
LPG Autogas is an alternative to petrol. LPG stands for Liquefied Petroleum Gas. Petrol engines have to be specifically converted to run on LPG and have an additional tank fitted (a bit like a gas cylinder).
LPG is available at a reasonable number of UK garages and is much cheaper than petrol, although it does give poorer fuel consumption.
However, before you start thinking about converting your car to LPG, it is important to remember that LPG is only cheaper because the fuel duty (tax) on it is much lower than the duty on petrol.
LPG isn't intrinsically cheaper, so if the government of the day decides to change the rate of duty on LPG, the cost could shoot up. LPG is good in London, however, as it makes you exempt from the London Congestion Charge.
Biodiesel & Ethanol
Since the 15th April, 2008, all petrol and diesel sold in the UK is legally required to include 2.5% biofuel. This is part of a government policy called the Renewable Transport Fuel Obligation (RTFO).
This 2.5% requirement applies to all regular fuels on sale at UK garage forecourts. The percentage is so small that all cars will run on the fuel without any risk of problems. These fuels are not labelled as including biofuels - it's just standard, now.
If you want to run a fuel with a greater percentage of biofuel, then you need to look at a specific biofuel product.
(Before doing this, however, be aware that many car manufacturers do not support the use of these fuels in their cars. While they may work fine, using an unsupported biofuel is likely to invalidate your car's warranty if any problems arise as a result.)
For diesel vehicles in the UK, biodiesel is the most common substitute for regular, oil-based diesel.
While there are biodiesel companies out there who make 100% biodiesel, this requires modifications to most cars for them to remain reliable so isn't recommended for most casual users.
More practical is to use a fuel that is a mixture of diesel and biodiesel. Some regular garages are now selling such fuels. The fuel names normally include a number indicating the proportion of biodiesel that has been added to regular diesel to make the fuel.
For example, B30 would be 30% biodiesel, 70% regular diesel.
For petrol car drivers, the choices are even fewer - bioethanol is the chosen biofuel substitute for petrol but availability of ethanol-based fuels in the UK is very limited.
If you do find one, it should have the same naming convention as biodiesel fuels - e.g. E30 would be a fuel containing 30% ethanol and 70% petrol.
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