November 23, 2014

Is All Petrol & Diesel The Same?

Filling up car with fuelIs all petrol and diesel the same, wherever you buy it from?

It’s a common question that often gives rise to heated debate between people who swear that their car runs better on fuel from XYZ Company and those who say that it’s all the same and they just buy the cheapest.

The problem is that most people don’t know how the fuel business works, and the truth is a little harder to find.

The Easy Bit – Premium Fuels (Shell V-Power, BP Ultimate, etc.)

Let’s start with the easy bit. Premium fuels, such as Shell V-Power Nitro+ and BP Ultimate are not the same as regular petrol or diesel fuels, although you can mix them freely with standard fuels without problems. Petrol like this is known as ‘super unleaded’ — confusingly, what is labelled as ‘premium unleaded’ on forecourt pumps (e.g. Shell Fuelsave) is actually standard petrol.

These ‘super unleaded’ premium fuels cost several pence per litre more, have a different, more sophisticated package of additives for cleaning and lubrication, and have a higher octane rating (petrol) or cetane rating (diesel).

Octane and cetane ratings describe the way a fuel burns inside an engine. Broadly speaking, a higher rating means a fuel will burn more efficiently and effectively inside your engine. This may improve performance and/or economy slightly – although not all drivers will see a noticeable difference.

Some supermarkets also offer their own super unleaded — notably Tesco, which offers Tesco Momentum 99 octane. This is usually cheaper than Shell V-Power or BP Ultimate but opinions vary as to whether it provides the same cleaning benefits and mpg improvements that are claimed for the top two fuels.

Tesco Momentum 99 super unleaded reportedly contains more ethanol than super unleaded fuels like BP Ultimate, which some people claim provides an octane boost but may not provide the same efficiency gains as the more expensive branded fuels. Like everything to do with fuel, people have different opinions, and the facts are hard to find.

Standard Unleaded and Diesel Fuels

The big debate is over whether the petrol and diesel sold by supermarkets is the same quality as that sold by branded fuel companies like Shell, BP, Esso and Total.

Let’s start with some known facts:

All fuels sold in the UK conform to the relevant British Standards. This means that they should all work in roughly the same way and you can mix them freely in your car’s fuel tank.

The standard petrol and diesel that’s sold on garage forecourts is mixture of two things:

  • ‘Base’ fuel
  • An additive package

The base fuel is the same for all companies – in fact, it usually comes from the same tanks at the local fuel refinery/distribution centre. What varies is the additives package that goes into the fuel. These additives packages are secret recipes of extra ingredients that help keep the engine clean and improve lubrication inside the engine cylinders.

Each fuel company has its own additives packages and these are different. So it is possible (but not common) for some drivers to feel that their car responds better to the additives used by one fuel manufacturer over those of another.

What About Supermarket Fuels?

There are all sorts of stories that go round about supermarket fuels, but the fact is that supermarket fuel tanker lorries are often seen filling up from the same tanks as branded fuel lorries (e.g. Shell, BP) – so the chances are that most of the time, the fuel they sell is the same, although again, it may have different additives packages.

However, one common story about supermarket fuel is that some supermarkets don’t have a regular fuel supplier. Instead, they buy odd lots of fuel from wherever it’s cheapest. This could (if it happened) lead to supermarket fuel having a more variable set of additives than branded fuels.

Not many people really know the truth about this business, and they are not the kind of people who will reveal all on the internet, so we will have to keep guessing as to whether there is any meaningful difference between supermarket fuels and branded fuels.

Comments

  1. Richard says:

    If you take a look at a list of refineries you’ll see that there really aren’t that many. So what happens is that standard grade fuels are pumped into each company’s tankers and the quality is the same. The difference comes in the additives that each company adds to its tankers. These might affect performance, so if you feel your car drives better on one type of fuel, keep using it. However, the fuel from different refineries may differ enough to blur any distinction. There are other variables too, but that would take several paragraphs to go into. As for supermarket fuel, it should all be of a minimum quality standard. So how come it is cheaper? There are three possible answers – a more flexible distribution network, fewer (or poorer) additives in the fuel, and thirdly, the fact that the big supermarkets are prepared to discount – they sell lots of things, not just petrol and chocolate bars, so they can afford to make a slight loss in order to attract customers into the stores.

    • @Richard

      Thanks for such a detailed comment, the point about the supermarkets selling fuel at a loss is a good one and something that seems likely to be true.

      Roland

  2. Lee Harding says:

    I drove for many years in the London area and never had any rhinitis or breathing problems. Looking back it seems that my problems started once ‘cleaner engine’ additives were introduced. (I know I’m going back a bit). Does anyone know of any research into the short & long term effects of these ‘cleaners’ on health? Also, do other countries use a different mix of base fuels and additives?

  3. John White says:

    I have a Nissan Pathfinder its just 12 months and have had several instances of it going into “safe Mode” Nissan dealer has checked it out and could not find a problem???? They also asked what fuel I used and when I said Tesco they said that is the problem “It is a lower grade fuel to Shell or BP” So this is what I have used and Nissan tech Centre have issued an instreuction to their garage outlets advising them to say Dont use suppermaket fuels?

  4. Mohammed sajed says:

    I’m a taxi driver , our biggest expenditure is fuel ,
    Which we use plenty off , from past experience
    Shell & BP petrol & diesel is 100% better purely
    Because of the additives used , supermarket fuel
    Is cheap & nasty , our vehicles became sluggish
    & performed poorly with supermarket fuel , we now use shell V power , it’s a lot better & cars do more miles per gallon , well worth the extra cost !

  5. Hi I’m happy to put the mileage difference to the test. I drive the same mileage every week on the same roads in a 2.7 Porsche Boxter. So today I will fill up from empty with Tesco premium unleaded and record the mileage on here. When it runs out I will repeat the process but with BP Ultimate…..results in a couple of weeks. : )

    • Hi Peter,

      It should be an interesting comparison, look forward to seeing the results!

      Cheers, Roland (SimpleMotoring.co.uk)

      • Okay just so you know I haven’t forgotten; I got 270 miles from Tesco premium unleaded. Just filled with BP Ultimate, results in a week. (This is mileage measurement only not performance).

      • I got the same miles from the BP roughly 270.

  6. Dear Friends,

    Talk about additives useful. Thanks.

    My particular problem, specific to metallic additives. Have a VW Polo. VW state clearly that metallic additives are HARMFULto their engines.

    From reading around it seems clear that Shell & Bp (probably true also of Esso top brands)certainly do not have metallic additives. Ie the top brands, more expensive, are metallic additives free.

    Will move to their more expensive ranges for what you say, Mohammed about better mileage and cheaper in the long run is pretty persuasive.

  7. simon collins says:

    I am launching this new product very shortly, which given the above discussion, i thought you may be interested in.

    https://www.facebook.com/peoplesfuelcard

    Its called the peoples fuel card and will enable drivers to pay with the card at the pumps and receive between 4-15p off the advertised price. There is no catch and you get to pay bi monthly or monthly, much like a mobile phone bill. If you are strapped for cash, you can still fill up and at a cheaper rate.

    i need 10,000 people for the company i am dealing with to do the deal.

  8. Mr Kevin Mohammed says:

    Hi there, ive had my Fiesta st for just under a year. And since day one, ive used BP ultimate. About six weeks ago, an Asda station opened on my doorstep. An as it was cheaper, I started to use that. But since I started using it my car has been very sluggish, and rough to drive. So from now on, im going back to the BP ultimate unleaded.

  9. I’m a Taxi driver and like most taxi drivers I stay well away from supermarket fuels! For two simple reasons – economy and for the health of my engine!

    Some engines take cheaper fuels better than others but Diesel engines particularly should stay away from supermarket fuels – they dont do EGR valves, injectors and DPFs any favours resulting in expensive repair bills. Vauxhall CDTIs and the PSA engines found in ford,Volvo,peugeot,and Citreons dont like supermarket fuels either resulting in problems mentioned above

    Only my opinion but shell is the best

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