I've been blissfully ignorant about supermarket petrol, but now hear that the reason it's cheaper than Shell /Esso etc is that they don't include all the additives that the main players do which help lubricate your engine.

Does anyone know the definitive truth about this, since I've only heard rumours up until now?

There is *nothing* wrong with supermarket petrol, it has to meet the British Standard required. However, other fuel companies do add things to their products, which generally gives better mpg and performance. What it does in the long term to your engine i have no idea, im sure an armchair expert will be along shortly to give an answer.

Anything in the fuel is going to be burnt – engines have an oil filler for lubes to go in…

From my own experience, I stopped refilling with Tesco's petrol as our car just didn't run as smoothly and did less mpg compared with the Shell/Esso petrol.

Anything in the fuel is going to be burnt – engines have an oil filler for lubes to go in…

Stick to electronics advice 😉 The fuel additives and the fuel itself is an important lube in several locations in engines where oil isn't seen – pumps, valve seats and stems to some extent etc.

In this case, however, supermarket fuel is designed to the standards your car was, it's fine, its just the extras in the other fuels can be even better than required.

My Pug is a boring old car. When fuelled with Tesco/Sainsbury's diesel it goes as if it was pulling a trailer. On Shell, Jet or Texaco (WTF with their prices?) it's a better car. Also, the supermarket fuel gives me only 38mpg whilst better and more expensive brands take it over 40mpg. The difference in purchase price is none if you consider the higher consumption.

Was sceptical but my ford diesel gets about 10% fewer mpg on tesco fuel.

I seem to be the opposite…I don't notice any difference in fuel consumption or mileage…I'm getting about 400 miles to a tank and about 35mpg no matter what petrol I use…as long as it meets the British Regs for fuel then I'm happy to use it…at the end of the day I'm not going to own the car long enough for any long term damage to hit my wallet (selfish thought but there you go!)…so I'll happily stick the cheapest juice in the vehicle.

IME diesels are much more reactive to improvements in fuel qualities.

I know a bloke who services "parts" for chemical plants

He says even people who work for Esso say they always buy shell

Yes, that may be bollocks but it is real bollocks!

(I buy from sainsbo's)

I always "buy" my fuel from Shell.. only beacause I have a fuel card, and also because they give you good money off vouchers.

I buy from the cheapest if I have the luxury, or the nearest if the orange light is blinking. Unless it's my petrol car, then it's got to be V-power or I'll have to switch to the boring low-boost maps and pootle about lol

I work in an oil refinery in central scotland and the one refinery supplies ALL the garages and supermarkets. (the different tankers are filled from the same tanks). But this may not neccessarily the case all over the country.FWIW I buy the supermarket stuff

Snake oil is being sold….

The base stock is likely to be identical. The v-power etc stuff (and many with additives) is very definitely different to the rest of the chaff; for those with any engine knowledge…

I have an engine with no knock feedback, however I listen to the knock through a set of amps and filters while tuning the car. On v-power I can run approximately 3psi more boost top end and can bring the spark advance in much quicker under load, leading to much better torque and power than the stock fuel (even the stock fuel from the same forecourt). This is repeatable and quantifiable, and leads to approximately 25 bhp more on a car of this sort. However, on a normal car the improvements are more questionable. At the end of the day any non-specialist car will run fine on any of the fuels available for it in the UK, there are minimum standards. A few can make use of the better fuels. Even fewer require the better fuels, but the owners will know it if its true.

When the sills are replaced I'll happily show anyone the difference between my "normal" fuel map and my "vpower" map, fortunately I've made it so I can switch between the two as required!

falkirk-mark – I work in an oil refinery in central scotland

LOL! Are you trying to keep the location a secret?

The V power stuff (or whatever the equivalnet BP stuff is), with the different RON values, is different from regular petrol. It has less volatile stuff which helps reduce any predetonation. The important thing to note is that it is made to a different specification at the refinery, it's not just additives.

As for 10% less fuel economy, I'd be very skeptical about those sorts of figures. Sure the different additives will make some sort of difference but I'd be amazed if it is that pronounced.

My mechanic mates used to rotate their fill ups between garage and supermarket fuel so they got the lube and the cheapness.
now they just get supermarket as 'they' say that supermarkets now sell the lube petrol.
My Bro adds some additives to his supermarket fuel (diesel)and said it makes a massive diffrence and is cheaper than garage.

I'll happily show anyone the difference between my "normal" fuel map and my "vpower" map

Not while I've a sock drawer needing sorting you won't.

LOL @ johnners!

I buy from Waitrose most of the time. Never noticed any difference in MPG when I've bought from elsewhere. In fact, the only times I tend to buy non-supermarket fuel is in Wales and when there my MPG gets shot to bits by having fun and driving harder than normal!

lol johnners – each to his own.

surely a lot depends on the state of storage tanks as well and how low garages let them get ? smaller garages may run tanks longer between refills dragging crud into the pipes ?

surely a lot depends on the state of storage tanks as well and how low garages let them get ? smaller garages may run tanks longer between refills dragging crud into the pipes ?

Certainly you have a point in some respects, little-used tanks tend to have old fuel in them but I've never seen crud come from any. In fact my 20 year old fuel tank was absolutely 100% spotless internally when I took it off, so gunge in fuel isnt a likely problem, however old fuel loses its RON rating, which in turn can allow det/pinking to occur. Newer cars (last 20 years ish) can detect this and will degrade performance to suit the poor fuel. For example, 99 RON v-power that has been left for months in a tank has a much lower RON, and likewise normal unleaded. So little-used garages will tend to have poorer fuel than those who refill regularly.

surely a lot depends on the state of storage tanks as well and how low garages let them get ? smaller garages may run tanks longer between refills dragging crud into the pipes ?

Following a conversation with a station manager last week about how slow the pump was – he said that they were about empty & expecting the tanker & the pump I was on was the furthest away & therefore the slowest

He also said that it was common practice to run a 'just in time' policy & only order fuel when they are almost dry
Big Shell station BTW

Next time I can't sleep I'm going to look up this thread and read coffeeking's comments. 😉

I drive a wagon with a 600 litre fuel tank and an engine that is covered with engine sensors so that the traffic manager can check fuel and oil consumption accurately. His verdict it doesnt matter what the sticker on the fuel pump says its all the same stuff.

Might be different for petrol but I cant believe its a 10 % difference. I cant notice any difference on my old BSA Thunderbolt and thats an engine designed for the full 4 star I.Q bashing leaded stuff.

I must admit that my Alfa's I used to drive, specifically the boxer engine variants, for no good or discernable reason, used to like Shell or Texaco system 3, and on filling up at a BP station, you'd notice the difference pretty quickly.

Not convinced it wasn't all in the mind, and the BP was a couple of pence cheaper back then. Oddly enough, I used to use Redex as well, but that didn't seem to make any difference at all, apart from creating lots of white smoke as it burnt off.

But the query I have is – where does supermarket petrol actually come from? A refinery? If so, how could it differ from anytthing else the refinery produces? Do the tankers stop, unload the fuel so a mad scientist can giggle manically and add a few drops of chemical and then refill the tanker?

Do refinerys have the abilityto "tailor the product" ? Can they "store" a dozen different types of petrol dependant on demand? Ie one for Texaco, one for Shell, one For BP, one for Esso, One for Morrisons, evt ect?

Fuel goes form Refienries and is stored in terminals where the chemicals are normally added

Nope they fill the tankers up with exactly the same base fuel, then add the additives to the tanks which require it.

gonefishin – Member

The V power stuff (or whatever the equivalnet BP stuff is), with the different RON values, is different from regular petrol. It has less volatile stuff which helps reduce any predetonation. The important thing to note is that it is made to a different specification at the refinery, it's not just additives.

Where have you got that from? I'm not necessarily disagreeing with you, but it is not my experience from when I worked in the fuel distribution business.

My exerpience is more along the lines of Falkirk-mark and pepper.

There are a handfull of refineries around the country owned by different companies (ie most of the fuel supplied to humberside/south yorks/lincs will come from Lindsey oil refinery at Grimsby owned by Total). They supply base Petroleum spirit (and other fuel oils) to terminals (again, any terminal could be owned by any oil company). Every local man and his tanker will fill up at that terminal. The majors usually have dispensers on the gantries so they can add their additive to the base Petroleum Spirit or Diesel at the terminal.

It's not quite as simple as that, because some companies will have their own storage elsewhere, then it all depends on the best price they can get. Sometimes they may send tankers to the nearest terminal, then other days use from their own storage. All the oil companies and oil distributors in Scotland, for example, will be using that same base stock from Grangemouth oil refinery. The same principle applies everywhere else, the nearest refinery will supply the majority of the stock, but in some parts of the country it could be coming from 2 refineries.

Did you know that there are only 12 refineries in the UK and, of those, only 1 in Scotland. The one in Scotland is at Grangemouth and it supplies 90% of fuel to Scotland (I only know this because I built a Diesel bunkering depot near there) I think it's BP owned but can't remember for sure.

There, Dracs sleeping like a baby now.

Have mates that work at two refineries outside of HULL. They claim apart fro the obvious grades at the pump, standard unleaded- v-power etc all are the same.

tesco basic comes out of the same megalitre containers as do the other 'branded' fuels. Niks refinery sells to 3 UK street brands and 2 supermarkets

Call me crazy but I just wait till the light on my dash starts flashing and then I look for a petrol station. I don't give a toss who owns it.

There's only one refinery near Hull and that is Lindsey Oil Refinery near Grimsby owned by Total (formally owned by Petrofina). I used to work out of Hull and there was alot of Fuel coming into the Humber on Barges from Rotterdam, but that was already refined. Rix Petroleum used to do alot of that, but all our fuel came from Lindsey. Your 'Niks' is most likely a terminal/depot with the base refined fuel coming in from Lindsey refinery or Rotterdam, whichever is cheapest.

Next time I can't sleep I'm going to look up this thread and read coffeeking's comments.

The curse of the Engineer I'm afraid, we [usually] love to understand how and why things work and, if possible, have a go ourselves even if just to prove it to ourselves. Thats how i know how my car deals with all the different fuels available to it. Only other engineers usually care! However normal peole like to know when things require fixing or when they need to know if something is worth doing.

sq225917 – Member

Niks? actually I think you probably meant Rix Petroleum, they are just a local fuel distributor, quite a big player in Humberside, but they definitely do not own any oil refinery.

I'm not sure I'm still that much clearer. Some people have stated that all fuel retailers are supplied from the same refinerys, meaning that all the fuel on sale is the same. But others have sounded quite authoritative when they state that fuel retailers do indeed have the opportunity to add additives to their fuel even if the same tankers and refinery's are used.

So does anyone know for sure if Shell diesel has additatives that Supermarket diesel doesn't?

If Shell are selling it as somethimg different to the normal stuff then it would need to be different (probably adding something to the road tanker). However if it does your car any long term good is another matter ( formula Shell debacle anyone)

I'll happily show anyone the difference between my "normal" fuel map and my "vpower" map

Not while I've a sock drawer needing sorting you won't.

Thats the funniest thing I've read on here in ages.

By Nik, i meant Nick Appleby.

Haven't noticed any difference since I switched from petrol to diesel.

My current diesel does pretty much the same mpg / performance irrespective of fuel.

My previous petrol engined car – Golf GTi mk V – returned better mpg, performance and drove smoother on V Power / BP Ultimate. The mpg difference actually made it more economic to pay the premium over supermarket fuel.

FWIW I have done a lot of work for a UK refinery and they are very secretive about the formulation of the many different additives used in their fuel blends…