Diesel just isn't diesel.

[lozz]

Yeah iagree, alittle smoke is not bad but,

http://www.youtube.com/watch?v=pclgBMeGYw8

itake it youve not been behind a leyland atlantian then,

what iwas getting at is this modern stuff is better, Roll with the changes,

[STALLED]

Here in AU - our 91ron fuel is 10% ethanol. The Mazda will run on it, but I won't use it for various reasons. Always gets 95 and above!

The 406 XU10 requires 95ron as a minimum (it states it on the filler cap) - it always gets 98ron, as it feels down on power/uses more on anything less. I sometimes might mix half a tank of 95-98 to get something in between, still seems to run alright!

As for diesel, I've never tried Ultimate which you can get here - does it really make that much of a difference? To me, diesel is diesel. Horrid to fill - goes all frothy, you end up in a nasty oil slick by the pumps.....

[Welly]

Bailes why would anyone think you are mad for buying better fuel? I've only ever put Super Unleaded in the Volvo for the last 5 years. I think it's only had '95' Unleaded in twice as an emergency, you get better MPG with higher octane fuel so it just about pays for itself and a petrol engine will benefit from cooler running around the valves and piston crowns, not to mention the ignition can be allowed to advance because no 'knock' will be detected so you get more BHP.

Yesterday I had to use the Ashtray to go to the tip and found the tank was empty (what a surprise) so went to a JET garage but to my surprise they're now doing 'super' I noticed all the Bikers were filling up with it anyhoo I grabbed Aurthur Tankful and filled me Garden machinery fuel dispensing receptacle with the stuff. I may ask her indoors if she's detected any performance increase or reduced pinking from the engine...............

Being a nosy f*cker I've gone done some research about JET because everyone used to say OMGJETFUELIZSHITLOL and the data sheet confirms their 'Super' is 97RON with a 5% ethanol content.

More more interesting is this statement from the owning companies website (MRH ltd):

"Having grown rapidly since it was established as Malthurst in 1997, MRH has become the UK’s leading independent service station owner and operator. In 2004 it acquired the operations of Kuwait Petroleum GB followed by large acquisitions from Texaco, BP and Esso. MRH now has over 370 company owned service stations in its extensive portfolio the majority of which are branded Esso, BP, Texaco and Jet"

From this 'ere website: http://mrhgb.co.uk/

So it appears that Texaco BP Esso and Jet are all owned by the same company (formally Kuwait Petroleum GB) but are the fuels any different between the brands I wonder?????

[trufflehunt]

So that's what happened to Q8 filling stations. I thought it was because I'd moved to Somerset.

[KozmoNaut]

Oh geez, not this aftermarket additives and octane bullcrap discussion again

Really? From empty I can get 75litres in my car. 2% of 75litres is 1.5litres.
That means that if I use a diesel that contains 7% bio I get an extra 1.5litres of biodiesel in my tank.

Now consider Millers Ecomax. It's an additive that comes highly recommended and gives a noticeable increase in performance, responsiveness and economy. And it can do all that by just adding a mere 75ml to my 75litre tank, or for an extra 'boost' you can use it at double strength which is still only 150ml. Suddenly the 1.5litres of extra biodiesel in a full tank of diesel seems like a massive amount.

There is nothing wrong with my car. It just really dislikes biodiesel, it's a trait of the 1.8TDCi.

Do you have rolling road or dyno figures to back up these assertions? Or are they based on what you "feel" and what you "expect" to happen from using an expensive additive?

Just as with STP, Redex and whatever else they're called, Millers Ecomax does nothing. The added amount is too minute to make any difference and it's just overpriced naphtha, anyway.

If it did anything positive at all, don't you think it would have been incorporated into the standard additive formulation years ago? Imagine the increased market value of being able to claim "our diesel increases performance, responsiveness and economy" compared to the competitors, and being able to back that up with hard evidence? But they can't, so they don't, thus proving that aftermarket additives are worthless and a waste of money.

The 1.8 TDCi is fine on biodiesel, people have been running TDCis on B100 (pure biodiesel) for years with the only troubles being a bit of deterioration of some non-essential rubber bits such as injector leak-off pipes, and those are easily replaced and won't make the engine run any worse, just get a bit messy on the outside.

There has been lots of issues with diesel fuel filters blocking up with a waxy substance in the UK over the last 12-18 months. Roughly around the same time the EU started introducing us to 7% diesel!

And although diesels may few well come from the same refinery it's just the base product. Biodiesel and other additive packages vary from garage to garage and are adding during the filling up process! Therefore diesel DOES very in quality from place to place.

The funny thing is that we've had B7 since 2011, which is significantly beyond your claimed 12-18 month time frame.

And please clarify. Are the additives added when the tanker truck is filled, when the tanker truck fills the petrol station tank, or when you fill up your car?

Because only the first option is true, and the same tanker truck can service multiple petrol stations from different chains, the delivered product doesn't change.

Otherwise, the tanker truck would have to carry a separate additive tank, or the petrol station would have to implement their own separate additive tanks to mix the fuel at the instant you're filling up. None of these things happen in the real world, only in the fevered minds of people who don't understand business and chemistry.

Here in AU - our 91ron fuel is 10% ethanol. The Mazda will run on it, but I won't use it for various reasons. Always gets 95 and above!

The 406 XU10 requires 95ron as a minimum (it states it on the filler cap) - it always gets 98ron, as it feels down on power/uses more on anything less. I sometimes might mix half a tank of 95-98 to get something in between, still seems to run alright!

As for diesel, I've never tried Ultimate which you can get here - does it really make that much of a difference? To me, diesel is diesel. Horrid to fill - goes all frothy, you end up in a nasty oil slick by the pumps.....

You're wasting your money putting higher-octane fuel in your car compared to what the manual states is required. It does nothing, octane is not a quality rating, it is simply a measure of how easy the fuel is to ignite. Higher octane fuel is actually harder to ignite! This helps with high-compression high-performance (usually turbocharged) engines, to prevent knocking. It does nothing in an ordinary normally-aspirated engine, apart from waste your money.

Bailes why would anyone think you are mad for buying better fuel? I've only ever put Super Unleaded in the Volvo for the last 5 years. I think it's only had '95' Unleaded in twice as an emergency, you get better MPG with higher octane fuel so it just about pays for itself and a petrol engine will benefit from cooler running around the valves and piston crowns, not to mention the ignition can be allowed to advance because no 'knock' will be detected so you get more BHP.

The only way your Volvo is getting better MPG and more performance from higher-octane fuel is if it's turbocharged, and even then it requires the ECU to be designed to take advantage of the increased ignition resistance. What does the manual state? Unless it states "95 RON minimum, 98 RON recommended for higher performance" or words to that effect, no benefit is gained from using higher-octane fuel.

The only reason you may be seeing a benefit is because you're expecting it, and unconsciously changing your driving habits to match.

In any case, I would love to see proof of your assertions. Do you have rolling road or dyno graphs to back it up? Do you have a measurement of cylinder head temperatures? Or are you just guessing based on what you expect to happen?

This is science, people. We deal in facts, not hearsay and "feelings".

So it appears that Texaco BP Esso and Jet are all owned by the same company (formally Kuwait Petroleum GB) but are the fuels any different between the brands I wonder?????

There is no difference between the brands, it simply wouldn't make any financial sense to create and maintain separate lines for each brand, and make sure every station is filled up from the correct truck. It's much easier and simpler to just fill up every station from the same truck.

[Welly]

Hi Kozmo, the Volvo is a 2.5 Turbo and the manual does 'recommend' 98 RON but you can use 95 minimum - I think it says to use 98 to get 'the best performance' or something.

I've got no evidence about in-cylinder temps only stuff that I sort of learnt when I was looking into Japanese cars years ago (I won't go into it, bloody things cost me a fortune) and I understood higher octane fuel reduces temperatures as it's less prone to pre-igniting. I am not an expert so please explain more if I'm wrong, I like to know things correctly if possible.

The debate about petrol will go on forever, I know Super Unleaded has additives added at the refinery but I'm not sure about 'normal' unleaded that gets shared around different outlets. To be fair, the trading names listed under MRH Ltd would seem to point that the fuel is the same between Texaco, BP, Jet and Esso. Shell petrol must be unique I guess (remember the problems they had with Shell 'Save' petrol or whatever it was called) it was taking out Lambda Sensors within hours.

[KozmoNaut]

Hi Kozmo, the Volvo is a 2.5 Turbo and the manual does 'recommend' 98 RON but you can use 95 minimum - I think it says to use 98 to get 'the best performance' or something.

In that case, 98 can definitely be beneficial, because the engine has been tuned for it. But it also has a knock sensor and the ability to retard timing, so it will run fine on 95 with a slight loss in power.

The silly stuff begins when people erroneously believe that their normally-aspirated everyday driver will somehow magically benefit from higher-octane fuel.

[Bailes1992]

Kozmo, I feel that you a bit of a pessimist. My car regularly see's a dyno. I get it done every 24k when I it gets a major service just for piece of mind. I get charged an extra £30 for a quick power run when I drop it in to be serviced. I've also had it dyno'd once elsewhere where it made nigh on identical figures.
My car makes 163bhp/400nms of torque so I can't see there being anything wrong with it at all. Also bare in mind it returns 60mpg and has on occasion returned over 70mpg on a good 60mph run.
The cars peak figure never really changes regardless of fuel, but the way in which it delivers it's torque does! The turbo can take an longer to spool and does it more gradually. That said we've never been able to mimic the stuttering or hesitating I feel on the dyno but they've seen it happen out on the road.

I can in fact feel the difference using additives and when not. Millers is highly recommended EVERYWHERE with THOUSANDS of happy people. Are you telling me that every single one of them is wrong? I am skeptical of everything so when I feel a difference you an guarantee it's not a placebo.
A few times I've added a single dose of millers I've gone to pull out of places or accelerate and the car has shot off much quicker than I've expected. The millers makes my engine feel more eager and 'tighter'. Millers is never used with premium performance diesels though, but I may give it a try!

And to say Biodiesel doesn't cause an issue when it blatantly does in my car is complete nonsense. I've had other work mates drive my car (also car enthusiasts, I'm fussy about who drives my car) and tell me how coarse and lazy it is on 7%.
There is hundreds of people online complaining about poor fuel economy and performance on B7.

Have a read of this!
http://www.rac.co.uk/press-centre/press ... -unexpect/
I can't imagine one of the UK's biggest motoring organizations printing something like that light heartedly.

I think you are mistaken when it comes to diesel the same everywhere. It's widely regarded that quality varies from station to station.
My old HDi90 wouldn't return more than 45mpg on Tesco diesel. Started filling up at Shell and was getting 55-60mpg EVERY SINGLE WEEK!
But of course, all diesel is the same.

[highlander]

None of my cars have ever run particularly well on the normal petrol from the Esso garage (it's a Tesco Express but the petrol forecourt has Esso fuel) at the end of my road; even my old Mk.1 Clio.

There wasn't as much "pull" from the engine, and the car always seemed to drink the stuff down faster.

Shell's normal petrol (whatever they're calling it now) seems to give the car slightly more peppiness (climbs through the rev range quicker), and the economy seems to be noticeably better.

BP seems very similar to Shell, except it's slightly more expensive.

I've not noticed any difference at all between Shell or BP's normal fuel or their premium fuel, other than cost. But then, that stuff's for big V8s and turbo/supercharged cars, so I don't bother with it anyway.

[Bailes1992]

If your petrol has a knock sensor then it should be able to fully adapt itself for increases in Octane.
I used to run my Focus on Tesco Momentum Unleaded as it used to pink like a b*astard on 95ron! But that didn't have a knock sensor.

[KozmoNaut]

Kozmo, I feel that you a bit of a pessimist.

No, I'm a skeptic and a realist.

he cars peak figure never really changes regardless of fuel, but the way in which it delivers it's torque does!

Well then, if there is a difference (more area under the curve), please show the dyno graphs that show this difference. If you can't show it on a dyno graph, it doesn't exist.

I can in fact feel the difference using additives and when not. Millers is highly recommended EVERYWHERE with THOUSANDS of happy people. Are you telling me that every single one of them is wrong?

.
Yes, they are wrong.

Or to put it another way, they've just spent money on an expensive additive, so of course they're going to "feel" a difference. It's all in their heads, a classic example of confirmation bias.

A few times I've added a single dose of millers I've gone to pull out of places or accelerate and the car has shot off much quicker than I've expected. The millers makes my engine feel more eager and 'tighter'.

So your car simple gained so much power and responsiveness that it almost got out of hand? Bullcrap.

Show the dyno graphs to back up this claimed increase in power and responsiveness. For the effect you mention, the turbo would have to spool up much faster than usual, which it won't do because you're still only burning the same amount of fuel and creating the same amount of exhaust. The ONLY way to achieve what you claim is to up the amount of fuel, by remapping or chipping, and of course no additive can do that alone.

And to say Biodiesel doesn't cause an issue when it blatantly does in my car is complete nonsense. I've had other work mates drive my car (also car enthusiasts, I'm fussy about who drives my car) and tell me how coarse and lazy it is on 7%.
There is hundreds of people online complaining about poor fuel economy and performance on B7.

Have a read of this!
http://www.rac.co.uk/press-centre/press ... -unexpect/
I can't imagine one of the UK's biggest motoring organizations printing something like that light heartedly.

If the RAC is anything like FDM here in Denmark, it's full of stodgy old geezers who are afraid of anything new, anything designed to improve the environment and anything they don't understand.

The issue they're talking about isn't down to biodiesel, it's down to the petroleum companies messing up their winter anti-gelling additives. It happens sometimes, it's not that unusual, and has nothing to do with biodiesel, other than biodiesel is a bit more likely to get. The increase from B5 to B7 cannot have the effect they mention, unless something else was changed as well, such as the winter additive package.

I think you are mistaken when it comes to diesel the same everywhere. It's widely regarded that quality varies from station to station.
My old HDi90 wouldn't return more than 45mpg on Tesco diesel. Started filling up at Shell and was getting 55-60mpg EVERY SINGLE WEEK!
But of course, all diesel is the same.

"Widely regarded" does not make something true. Car enthusiasts on the whole are blithering idiots, without the slightest understanding of chemistry or the nature of the combustion cycle. What probably happened is that you filled up at a station that hardly sees any customers. Fuel can go skunky with age, it's perfectly normal. And perhaps your existing prejudices against "supermarket fuel" kicked in as well.

If your petrol has a knock sensor then it should be able to fully adapt itself for increases in Octane.
I used to run my Focus on Tesco Momentum Unleaded as it used to pink like a b*astard on 95ron! But that didn't have a knock sensor.

No, only if your engine has a knock sensor AND the proper mapping for 98 will the higher octane fuel have any effect. As I mentioned earlier, if 98 octane isn't specifically mentioned in the manual, you will gain nothing from using it.

And your Focus probably had massive carbon buildup, which leads to increased compression, which leads to knocking. A classic sign of a mistreated engine.

[dirtydirtydiesel]

, Just my two penith worth.
Loads of people I know personally in the trade say stay away from supermarket crap , even our local Diesel specialists agree that it's no good for the long term health of your fuel system. (& they are highly reguarded by all the trade & main dealer garages in Leicestershire)
In my own experiance my 110hdi clatered like a bastard on Morrisons diesel but is loads quieter & smoother & more economical on ESSO & SHELL
But just there std fuel save stuff so I'm sticking with that.
As for petrol I have to agree with KozmoNaut, I used to have a Astra GTE 16v back in the early 90's & that had a octane plug under the bonnet one side was for 95ron the other was for 98ron, this altered the ingnition map to suit the higher octane fuel (altered the advance).
On the dyno it went from 148bhp to 156 with ESSO super+ with the plug on 98 & the dyno operater said that the car was noticably crisper through the rev range.
A lot of modern higher performace petrol cars can tell via there knock sensor which grade of fuel you've filled up with & alter automaticly to suit.
I had a e36 M3 3.2 for a short time & that had a sticker on the insturments next to the fuel gauge that said 'warning 98ron fuel or higher only'

[mjb]

Just as with STP, Redex and whatever else they're called, Millers Ecomax does nothing. The added amount is too minute to make any difference and it's just overpriced naphtha, anyway.

And cleaning agents which are frequently used to clear catalytic converters or engine internals don't do anything either, despite countless reports of cars failing emissions tests, then passing easily after a short run after a fuel additive?

If it did anything positive at all, don't you think it would have been incorporated into the standard additive formulation years ago? Imagine the increased market value of being able to claim "our diesel increases performance, responsiveness and economy" compared to the competitors, and being able to back that up with hard evidence? But they can't, so they don't, thus proving that aftermarket additives are worthless and a waste of money.

If adding a stupid great supercharger did anything positive at all, don't you think it'd be added to every car under the sun? Imagine the increased market value of being able to claim "our 1.1 eurobox produces 300hp" compared to the competitors, and being able to back that up with hard evidence? But they don't thus proving that superchargers are worthless and a waste of money.

Here in AU - our 91ron fuel is 10% ethanol. The Mazda will run on it, but I won't use it for various reasons. Always gets 95 and above!

The 406 XU10 requires 95ron as a minimum (it states it on the filler cap) - it always gets 98ron, as it feels down on power/uses more on anything less. I sometimes might mix half a tank of 95-98 to get something in between, still seems to run alright!

As for diesel, I've never tried Ultimate which you can get here - does it really make that much of a difference? To me, diesel is diesel. Horrid to fill - goes all frothy, you end up in a nasty oil slick by the pumps.....

You're wasting your money putting higher-octane fuel in your car compared to what the manual states is required. It does nothing, octane is not a quality rating, it is simply a measure of how easy the fuel is to ignite. Higher octane fuel is actually harder to ignite! This helps with high-compression high-performance (usually turbocharged) engines, to prevent knocking. It does nothing in an ordinary normally-aspirated engine, apart from waste your money.p

Funny that, I did extensive testing (several months at 120 miles per day driven at exactly the same speed) with various fuels when I had an XU10 and found a massive difference in economy between supermarket 95RON, branded 95RON and branded 98RON. branded 95 delivered the best mileage for the money followed very closely by branded 98, with supermarket fuels having a drastic ill effect - one notoriously cheap fuel (asda) even reduced distance per litre by about 30%. Now (in the UK) the relative difference in price between branded unleaded and super has shrunk, it's now a false economy to put anything but premium fuel in.

The only way your Volvo is getting better MPG and more performance from higher-octane fuel is if it's turbocharged, and even then it requires the ECU to be designed to take advantage of the increased ignition resistance. What does the manual state? Unless it states "95 RON minimum, 98 RON recommended for higher performance" or words to that effect, no benefit is gained from using higher-octane fuel.

My more recent engines (NA V6, I6 and V8s with relaxed maps) have all benefited from premium fuel. The economy difference under controlled conditions is massive. 100RON fuel tested in these cars delivers a further economy benefit, and since economy is a measure of power output against fuel input, it is a given that premium fuels have more usable power per volume unit than cheap fuels. Whether an engine can deliver increased maximum power output on a different fuel is a debate which can only be answered on a dyno... like Fifth Gear did: http://www.youtube.com/watch?v=gQghB4asSnI

Here's another test conducted with a pair of NA cars: http://www.pistonheads.com/gassing/topic.asp?t=302977

And then there's the detergent additives they have in premium fuel. Have you any proof to say they don't do anything?

There is no difference between the brands, it simply wouldn't make any financial sense to create and maintain separate lines for each brand, and make sure every station is filled up from the correct truck. It's much easier and simpler to just fill up every station from the same truck.

and every branded item in a supermarket is exactly the same as it's own-brand value range equivalent as well...

[trufflehunt]

Rather like Kausmonaut..., you seem to be picking and choosing your science , according to your prejudices.
With you, it's..' no engine cleaner/catalylist additves work..'
With Kausmo... , he reaches for '.. probably this.., probably that..'. to discount the findings of others..

[KozmoNaut]

And cleaning agents which are frequently used to clear catalytic converters or engine internals don't do anything either, despite countless reports of cars failing emissions tests, then passing easily after a short run after a fuel additive?

These cleaning agents and additives are already in the standard mandated additive package that all fuel must adhere to according the EU-wide regulations. The reason these aftermarket additives seem to work is because part of the "cleaning procedure" is getting the engine warm and running it through the rev range. A good old-fashioned Italian tuneup will do the exact same thing.

The only cleaning additive that actually works is stuff like Seafoam or "Subaru Upper Engine Cleaner", and they still do nothing if you just pour then in the tank. You have to add them to the oil and suck up the rest through a vacuum line, then let the engine sit for a while, followed by running it moderately hard and then change the oil because of all the gunk that gets deposited. And they still only have an effect on severely coked-up engines. Engines that have been mistreated for years. Treat your engine right, get it warm, work it through the revs instead of puttering around below 2000rpm always, and you will never need an engine cleaning additive.

If adding a stupid great supercharger did anything positive at all, don't you think it'd be added to every car under the sun? Imagine the increased market value of being able to claim "our 1.1 eurobox produces 300hp" compared to the competitors, and being able to back that up with hard evidence? But they don't thus proving that superchargers are worthless and a waste of money.

You're being silly now. Adding a big great supercharger has some obvious major drawbacks. For one, it reduces fuel economy severely. It also increases the cost and complexity of the drivetrain, and it requires strengthening other parts of the engine to withstand the boost pressure.

On the other hand, adding a performance- or mileage-improving additive to fuel has only one drawback, a small additional cost, which can easily be recouped by the increased profits from having "the best petrol on the market, guaranteed!".

Funny that, I did extensive testing (several months at 120 miles per day driven at exactly the same speed) with various fuels when I had an XU10 and found a massive difference in economy between supermarket 95RON, branded 95RON and branded 98RON. branded 95 delivered the best mileage for the money followed very closely by branded 98, with supermarket fuels having a drastic ill effect - one notoriously cheap fuel (asda) even reduced distance per litre by about 30%. Now (in the UK) the relative difference in price between branded unleaded and super has shrunk, it's now a false economy to put anything but premium fuel in.

Extensive testing meaning "I put some fuel in my car and drove it, in wildly varying weather conditions, on different routes, in changing traffic, with changing loads, different number of passengers, in different moods etc. etc."?

Do you have any concrete proof as a result of your "testing", or are we just supposed to take your word for it? Put your car on a dyno with different fuels in the tank, it's the only way to know whether it had an effect or not.

My more recent engines (NA V6, I6 and V8s with relaxed maps) have all benefited from premium fuel. The economy difference under controlled conditions is massive. 100RON fuel tested in these cars delivers a further economy benefit, and since economy is a measure of power output against fuel input, it is a given that premium fuels have more usable power per volume unit than cheap fuels. Whether an engine can deliver increased maximum power output on a different fuel is a debate which can only be answered on a dyno... like Fifth Gear did: http://www.youtube.com/watch?v=gQghB4asSnI

Here's another test conducted with a pair of NA cars: http://www.pistonheads.com/gassing/topic.asp?t=302977

The economy difference is not "massive", it is extremely minute, and only applicable to engines that are tuned or can be tuned to make use of the higher octane rating.

You're absolutely wrong when you say that premium fuels have more usable power per unit. They do not, as the octane rating is not a measure of quality, it is not a measure of energy content.

In fact, higher-octane petrol has slightly less power per unit than ordinary or lower-octane fuel, because the ignition-inhibiting ingredients and additives have a lower energy content, thus lowering the combined energy content. And all higher-octane fuel today is made by adding more ethanol to the petrol, since ethanol is both cheap, and it has an octane rating of about 110. Only high-octane petrol with MTBE is ethanol free, and it's very close to being completely outlawed, due to environmental and health issues, and good riddance.

Engines that can make use of higher-octane petrol by advancing timing or higher compression can make more power, but that is not an effect of a more powerful fuel. It is an effect of the more aggressive tuning of the engine being able to extract more of the total power of the fuel. If the engine is not tuned for it, you will see no benefit.

I've seen the Fifth Gear test and it's true that Turbo-charged or otherwise highly-tuned cars can see a benefit from higher-octane petrol. On anything else, the difference is either non-existent or so small as to be statistically insignificant. Most dynos have a margin of error much larger than the "differences" they found.

As for the Pistonheads test of NA cars, those are high-performance machines. The BMW M3 absolutely has a fuel and timing map that can take high-octane fuel into account, and I'm fairly sure the MR2 does as well, being a reasonably hardcore sports car. Still, the gains are rather minute. You need a minimum of a 10hp increase to even feel a difference, and the hyperbole in the article is just that, hyperbole for the sake of an article. Again, you will not see those kinds of increases on a normal everyday car, and even if you did get a 3-4hp boost, it would mean absolutely nothing against the added cost of the super premium high-octane petrol.

And then there's the detergent additives they have in premium fuel. Have you any proof to say they don't do anything?

Of course there are detergents and additives in premium fuel. Do you know why? Because they're in the ordinary fuel as well! They're mandated and have to be added to adhere to the standards. The very same standards that the engine in your car was designed for.

Peugeot et. al. don't design and test their engines using premium fuel, they use the standard fuel as mandated and available everywhere, in order to make sure their engines can be sold in all markets.

Oil companies claim that there are more additives in their premium fuels, but they have yet to prove that this makes a difference compares to the mandated amount of additives. All they can do is show us pictures of fancy red Ferraris driving fast and harp on about their connection to Formula 1 or whatever. They have yet to put hard facts on the table, showing us that their premium fuel is better for the engine.

and every branded item in a supermarket is exactly the same as it's own-brand value range equivalent as well...

In a lot of cases, yes. Own-brand products are produced at the very same factories as the name-brand products, usually to the same standards.

Of course there are exceptions (such as Corn Flakes, for some reason), but usually the only difference is in the packaging.