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  • FIRST POST
    • trailingspouse
    • By trailingspouse 5th Dec 17, 5:46 PM
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    trailingspouse
    Supermarket fuel v the rest
    • #1
    • 5th Dec 17, 5:46 PM
    Supermarket fuel v the rest 5th Dec 17 at 5:46 PM
    I'm sure this has been asked before - apologies.

    OH is adamant that supermarket diesel is poor quality and bad for the engine. More than that, he prefers to use the 'premium' variety, even at the non-supermarket filling stations. Personally I'd be happy enough to use the supermarket stuff mostly because it's a lot cheaper but also because I'm at the supermarket at least once a week, whereas I have to go out of my way to go to our nearest non-supermarket one. So cheaper, and more convenient.

    Is he right? Or doesn't it make that much of a difference?
Page 2
    • tberry6686
    • By tberry6686 6th Dec 17, 9:27 AM
    • 974 Posts
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    tberry6686
    Virtually all fuel in a given area will come from the same refinery. The only differences are in the additives that the differing companies use, so the actual fuel for all filling stations coming from that refinery is exactly the same.
    • AdrianC
    • By AdrianC 6th Dec 17, 9:33 AM
    • 15,748 Posts
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    AdrianC
    I was told by someone who worked for Mobil for many years
    Originally posted by reeac
    Uh-huh. No vested interest, then.

    that supermarket fuel met the requisite spec. but only marginally so.
    No point in massively exceeding it, is there?

    There might, therefore, be a slight beneficial/harmful effect which only showed up after some years
    Or there might not.

    Lovely word, "might".
    • takman
    • By takman 6th Dec 17, 9:56 AM
    • 2,897 Posts
    • 2,409 Thanks
    takman
    I was told by someone who worked for Mobil for many years that supermarket fuel met the requisite spec. but only marginally so. There might, therefore, be a slight beneficial/harmful effect which only showed up after some years so those who religiously change their cars every 3 years wouldn't encounter it. Personally I buy from non- supermarket filling stations but that may be to some extent because our Waitrose doesn't sell petrol.
    Originally posted by reeac
    Specifications are designed to ensure a product meets the requirements to work effectively. So even only marginally meeting the specifications means that it will work perfectly fine and will not harm the car. Manufacturers know the spec so will design their cars to run on fuel to this spec.

    This base fuel which meets the spec is then used by companies like shell with a few additives (which they confirmed in an email to me). So if the base fuel was harmful a small amount of additive won't change that.

    The only possible harmful thing about supermarket fuel which i have seen on previous discussions is that they may allow a higher water percentage in their tanks compared to branded fuel.
    • Stoke
    • By Stoke 6th Dec 17, 10:21 AM
    • 1,998 Posts
    • 842 Thanks
    Stoke
    I just use supermarket. I don't really care, but my car is naff so....
    • BeenThroughItAll
    • By BeenThroughItAll 6th Dec 17, 10:39 AM
    • 4,614 Posts
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    BeenThroughItAll
    Virtually all fuel in a given area will come from the same refinery. The only differences are in the additives that the differing companies use, so the actual fuel for all filling stations coming from that refinery is exactly the same.
    Originally posted by tberry6686


    Actually it probably won't. It will come from the same distribution terminal (i.e. Seal Sands, Thurrock, etc) but the road fuel is actually often manufactured at the terminal itself.


    The base fuel stocks (spirit/light oil, FAME, Ethanol, butane, additives etc) are delivered to the terminals from all over the place, different refineries, sometimes by bulk liquid or gas tanker, bio-refineries) and tanked - then they're blended to a base recipe (which is the same for all the retailers with only one exception).


    The standard road fuel blend is then loaded to the tankers with the retailer-specific additive injected into the fill via nozzles in the bulk-load filler - that's the only difference in the stuff delivered to the filling stations, and those additives are added in tiny, tiny quantities. The additive packs are almost exclusively detergents of different types; the claims that some 'branded' fuel is better because of power-enhancing additives are quite simply utterly false. Wherever you buy your 95RON or 98RON fuel, it'll be the same basic blend plus additives.


    However - due to the vagaries of the blend process, and the way base stocks are stored and used, the tanked standard road fuel does sometimes only meets the standards, and on other occasions significantly exceeds them.
    • IanMSpencer
    • By IanMSpencer 6th Dec 17, 11:25 AM
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    IanMSpencer
    I think this goes back a good few years where originally there was a rumour (or even fact) that they sold petrol from a different source, a by-product of chemical manufacturing (ICI comes to mind). My imagined memories of this were that Jet also sold the stuff, and there were stories of black specks in the fuel.

    Regardless of that, this has persisted and is certainly now a myth today. So many people run cars on supermarket fuel (often exclusively so) that if there were a problem, then it would have come out.

    Fuel is also governed by EU standards, so they have to sell fuel that conforms to ensure it is suitable for all cars. Also, legally, if it were not of satisfactory quality, there would have been some sort of trading standards action by now.

    The branded fuels may well have additives, but the question is more whether those additives actually produce a useful difference, and it seems to me that where the additives do increase the accessible energy within the fuel, it is not clear whether the premium for that extra energy outweighs the cost. In the days before electronic ignition, there were problems with fuel additives causing engine damage - specifically Formula Shell - which caused inlet valve damage, I guess probably because it caused ignition mis-timing.

    With electronic ignition, petrol engines pretty much adapt to any old junk that they are fed with, though some cars may recommend using premium products (which is not the same as requiring them).

    Diesel is pretty much diesel. There are a few things that are messed around with - in winter, especially in Europe, it needs additives to stop it solidifying, and the brands like to add cleaners on the basis that it is messy stuff and people believe that it will help their engine. I'd tend to assume that manufacturers designed and tested their engines on typical fuel rather than assuming their customers would run them on premium fuel, so I would not expect a premium fuel to be a requirement to get long engine life out of a car.
    • reeac
    • By reeac 6th Dec 17, 11:38 AM
    • 1,138 Posts
    • 456 Thanks
    reeac

    Diesel is pretty much diesel. There are a few things that are messed around with - in winter, especially in Europe, it needs additives .....
    Originally posted by IanMSpencer
    Puts a new slant on that Christmas carol where Good King Wenceslas was gathering Winter fuel then.
    • Car 54
    • By Car 54 6th Dec 17, 12:21 PM
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    Car 54
    Does it make any difference what sort of car it is?
    Originally posted by trailingspouse
    Only that people who drive certain types of car seem more likely to buy the snake oil.
    • n217970
    • By n217970 6th Dec 17, 12:51 PM
    • 243 Posts
    • 178 Thanks
    n217970
    As many above I have been using supermarket fuel for a long time with no issues. Rarely I fill up at Shell near home if I am short of getting to the supermarkets near work. I can tell no difference between the two.

    The only time I have ever sensed a difference in fuel was when I used to fill up from a haulage companies own on site tank. The diesel was obviously bought for the trucks but the car ran noticably smoother, for those that have experienced them the effect was similar to a low setting on a tuning box. No idea what the difference was to the local Shell. Less/different/more detergents?
    • davetrousers
    • By davetrousers 6th Dec 17, 12:58 PM
    • 5,576 Posts
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    davetrousers
    Remember Winter diesel will be coming in soon, so it may skew your results.
    .....

    • almillar
    • By almillar 6th Dec 17, 1:21 PM
    • 7,118 Posts
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    almillar
    Joe Horner - that made me laugh out loud, and that's exactly what I've done in the past... Yes, he does reckon he can tell.
    You may laugh, but a blind test might help change HIS mind, OR YOUR mind. Empty tank, fill it up, let him drive till it's empty. Don't tell him what you put in. Let him guess. Repeat a few times. Let him do the same to you.

    Or, just buy it at the supermarket and complain to him about how much it's costing you to get the expensive stuff!

    The problem is that you'd have to run a car for 100,000s of miles on just one fuel, and take it apart to see how clean or otherwise it is, to know how well all the fancy stuff has or has not protected your engine. That's why people can swear by it whilst other people say it's rubbish.

    I know for a fact that my petrol car wants super unleaded (that's to do with octane levels, not additives) because I'm one of the saddos that actually reads manuals!
    • Tarambor
    • By Tarambor 6th Dec 17, 2:01 PM
    • 1,756 Posts
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    Tarambor
    Given that the vast majority of fuel sold in this country is from supermarkets (I recall it being around 80%) and there aren't piles of cars broken down at the roadside then clearly it isn't as bad as the more hysterical in this thread are implying.
    • RichardD1970
    • By RichardD1970 6th Dec 17, 2:26 PM
    • 2,709 Posts
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    RichardD1970
    Remember Winter diesel will be coming in soon, so it may skew your results.
    Originally posted by davetrousers
    • EssexExile
    • By EssexExile 6th Dec 17, 3:52 PM
    • 2,486 Posts
    • 1,657 Thanks
    EssexExile
    No need for that, just light a small bonfire under the fuel tank to warm up its contents.
    Tall, dark & handsome. Well two out of three ain't bad.
    • vikingaero
    • By vikingaero 6th Dec 17, 5:41 PM
    • 10,330 Posts
    • 13,027 Thanks
    vikingaero
    My advice is thus:

    (1) If it's a lease/PCP car that goes back after 3 years run it on supermarket fuel.
    (2) If you feel your car runs better on branded fuel, and you can afford it, then run it on branded fuel.
    The man without a signature.
    • trailingspouse
    • By trailingspouse 6th Dec 17, 5:50 PM
    • 2,458 Posts
    • 3,523 Thanks
    trailingspouse
    Thanks all.

    I've finished the popcorn - anyone fancy a hotdog?
    • motorguy
    • By motorguy 6th Dec 17, 6:49 PM
    • 15,825 Posts
    • 9,118 Thanks
    motorguy

    (2) If you feel your car runs better on branded fuel,
    Originally posted by vikingaero
    Then you would be kidding yourself because it wont.


    and you can afford it, then run it on branded fuel.
    Originally posted by vikingaero
    If you're down to worrying about "affording" the extra 2p or so per litre (if even that) then i would suggest you've bigger problems to worry about than "will my car run better on branded diesel?"
    You are not special. You are not a beautiful and unique snowflake.
    • Inner Zone
    • By Inner Zone 6th Dec 17, 7:36 PM
    • 1,947 Posts
    • 1,067 Thanks
    Inner Zone
    I'm sure this has been asked before - apologies.

    OH is adamant that supermarket diesel is poor quality and bad for the engine. More than that, he prefers to use the 'premium' variety, even at the non-supermarket filling stations. Personally I'd be happy enough to use the supermarket stuff mostly because it's a lot cheaper but also because I'm at the supermarket at least once a week, whereas I have to go out of my way to go to our nearest non-supermarket one. So cheaper, and more convenient.

    Is he right? Or doesn't it make that much of a difference?
    Originally posted by trailingspouse
    Not again...........
    • ess0two
    • By ess0two 6th Dec 17, 7:57 PM
    • 2,914 Posts
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    ess0two
    I work at Stanlow oil refinery.
    Base fuels are exactly the same, additives and detergents vary for different customers.
    Official MR B fan club,dont go............................
    • Iceweasel
    • By Iceweasel 6th Dec 17, 10:00 PM
    • 4,264 Posts
    • 3,116 Thanks
    Iceweasel
    I work at Stanlow oil refinery.
    Base fuels are exactly the same, additives and detergents vary for different customers.
    Originally posted by ess0two
    A bit like whisky then - all the same.

    Some folks can't tell a straight malt from a blend with 49% imported spirit made from potatoes.

    Especially if they pour in in a glass with lemonade or even cola and tell you they've never had a problem getting drunk.
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