Supermarket Fuel, Facts Please

[Exige77]

I happily run my performance cars on Tesco 99.

It’s my preferred fuel. Never had any issues.

On continental excursions, happily run on Shell 100 Octane. I can’t say I’ve noticed any difference.

[yakka]

Had to fill a non dpf Astra with Morrisons finest and after a steady run of 30 miles at about 60 it blew nations of soot out when I booted it.
Never seen that with Shell.
Is there a reason for more ash?

[Willy Nilly]

RobM77 said:

I'm a bit perplexed by the cynicism shown here towards different fuels.

The differences are easily tested and I'm sure we've all seen the results of such tests. As I'm sure many people here have, I've done my own tests for my very repeatable and quite long commute and I get 10% better mpg on Shell V Power diesel compared to standard Shell diesel. Every single time I do a comparison test I get pretty much the same result - it can't be the same fuel or anywhere near. Shell std vs BP std is a different and more subtle question of course, and I doubt it's one I could usefully probe in the same way, but surely others have?

I'm particularly confused by the attitude of 'it all comes from crude oil, therefore it's all the same', because surely there's a long road between a crude oil refinery and the forecourt pump, involving various additives?

Most bizarre is the "it all meets the standards, so it's all the same" attitude, which surely is like saying that because a McLaren Senna passes the same MoT as a Ford Fiesta, they are the same car?

I doubt your tests are anything like scientific

[Heaveho]

TooMany2cvs said:

<shrug>
Then perhaps don't whine that your engine will "blow up" at the first sign of "piss", since you clearly made the conscious choice that it it wouldn't take 95...

...of any brand...

You can't read. I didn't whine about it. I explained why I don't use it. I would try 99 R0N from any supermarket if they all sold it, as it is, only Tescos do. I don't lump that in with my general description of supermarket fuel, as it clearly is decent stuff. I monitor knock in the modified car, and it is no different to Shell in that car. Many vehicles have an ECU set from the factory that is able to cater for the poorest fuel they are likely to contend with, but can advance settings when fed something better. In my experience some cars will need some time to learn the difference, so if you just bung one tank of more expensive fuel in, you may not see any immediate benefit.

I notice a difference on most of my cars, the Boxster being the exception. It seems to make no difference on that performance wise, haven't checked the mpg.

[Cyder]

So 12 pages and no facts yet?

FWIW I run the 350Z on Tesco 99 with no issues and it's so much cheaper than V-Power.

[GIYess]

I have no Tech no how on the matter of fuel. I had a remapped Vectra that was run almost exclusively on supermarket diesel from 62,000 miles to 150/160,000 miles. Never had any injector issues. (I did have a water pump failure but if fuel caused that then I would be worried.)
But.....
I'm scared to run my Mondeo on Tesco fuel because I definitely do not want to change another set of injectors. Do the additives not care for the injectors? My mechanic says.... (I know) that the Pezo crystal injectors in the Mondeo are sensitive to fuel choice. What do you think?

[TooMany2cvs]

GIYess said:

But.....
I'm scared to run my Mondeo on Tesco fuel because I definitely do not want to change another set of injectors. Do the additives not care for the injectors? My mechanic says.... (I know) that the Pezo crystal injectors in the Mondeo are sensitive to fuel choice. What do you think?

Neighbours of mine are just scrapping their 53 Mondeo diesel for a number of reasons, including shagged injectors leading to excessive emissions. I think it's on about 180k. It definitely won't have been run on premium fuel while they've had it, just whatever's available easily - no supermarket stations around here, though. Two of the three stations within ~20 miles are Texaco, one's an off-brand indie.

[bitchstewie]

So what's the view on ethanol please?

Seems to come up especially around Momentum and I find my M140i feels zippier on that (I can often hear a little more of a "rasp" if I put my foot down with Sainsbury's Super).

Read some things they all have ethanol in them, read other things and my fuel lines will disintegrate by teatime.

[TooMany2cvs]

bhstewie said:

So what's the view on ethanol please?

Simple fact: The current European unleaded spec is max 5% ethanol, and hasn't changed since unleaded was introduced. 10% may be coming soon, but 5% will remain available alongside it as "protection grade".
Simple fact: 10% is common in other European countries (nearly a decade in France), and has been the default in the US since the 70s.
Simple fact: All new cars sold in Europe since 2011 must be E10-safe.

[Mr2Mike]

RobM77 said:

I'm a bit perplexed by the cynicism shown here towards different fuels.

The differences are easily tested and I'm sure we've all seen the results of such tests.

Indeed, and these tests show that for most average cars the difference is negligible amd often with experimental error.

[RobM77]

Willy Nilly said:

RobM77 said:

I'm a bit perplexed by the cynicism shown here towards different fuels.

The differences are easily tested and I'm sure we've all seen the results of such tests. As I'm sure many people here have, I've done my own tests for my very repeatable and quite long commute and I get 10% better mpg on Shell V Power diesel compared to standard Shell diesel. Every single time I do a comparison test I get pretty much the same result - it can't be the same fuel or anywhere near. Shell std vs BP std is a different and more subtle question of course, and I doubt it's one I could usefully probe in the same way, but surely others have?

I'm particularly confused by the attitude of 'it all comes from crude oil, therefore it's all the same', because surely there's a long road between a crude oil refinery and the forecourt pump, involving various additives?

Most bizarre is the "it all meets the standards, so it's all the same" attitude, which surely is like saying that because a McLaren Senna passes the same MoT as a Ford Fiesta, they are the same car?

I doubt your tests are anything like scientific

As a former scientist, I'm well aware of that. However, in practise, if you do the same test for something this simple ten times and get the same result +/- <10% every single time (for example, results could be: 10%, 9.5%, 10.2%, 9.7% etc), statistically that's fairly conclusive (if there is no other plausible reason why you'd get those same results). To minimise the latter, I've measured the mpg in two different ways and guess what? same results again. The likelihood of me achieving those results by chance is vanishingly small. I've even done it for two different cars and yes, same result again. As I allude to above, my primary point was actually referring to the many tests done by others in a more scientific setting and the secondary point was how one's own tests mirror these findings. Your criticism is valid in many contexts, but not in this context - this is a very simple test of how much fuel is used per mile driven, it's not rocket science!


Edited to add: Let's be clear about this and restate what I said above in my first post: for more subtle issues such as Tesco fuel vs Shell fuel I think anecdotal evidence is indeed next to useless, especially when we're looking at reliability, rather than a simple number such as mpg. I agree with you there.

Edited by RobM77 on Thursday 23 August 11:46

[TooMany2cvs]

Again, we're heading way off topic, but less so than the octane question. But could somebody please explain to me what actually is the difference between superdiesel and vanilladiesel? Petrol, it's easy. Point to octane numbers, knock resistance. Job jobbed.

But AIUI diesel's nowhere near the same simplicity...

[NickGRhodes]

TooMany2cvs said:

Again, we're heading way off topic, but less so than the octane question. But could somebody please explain to me what actually is the difference between superdiesel and vanilladiesel? Petrol, it's easy. Point to octane numbers, knock resistance. Job jobbed.

But AIUI diesel's nowhere near the same simplicity...

"One characteristic of V-Power diesel is that it is a lot clearer and odourless than normal diesel, mainly due to the synthetic GTL component.

The fuel is slightly less dense than regular diesel so, per volume, the unit energy is actually lower than regular diesel. This is offset, as the fuel tends to ignite more readily (and thus has a higher cetane rating) than regular diesel, and a side benefit of this is that it tends to produce less soot during combustion"

https://en.wikipedia.org/wiki/Shell_V-Power#V-Powe...

[Peter3442]

I used to work on a site where fuels and lubricants were developed. In those days, there were probably more possibilities for differences in refining and blending as more refneries were operated by the big oil companies. I don't know how that is handled these days. However, the more important factor was the effect of additive packages. For fulels, Tthese have (or had) several objectives:
- keep the fuel system clean and reduce deposits in the combustion chamber and exhaust port.
- improve 'ignitability'.
- reduce/modify knock characteristics of gasoline
- protect valve seats
.....

Overall, the intention was to improve some measure of performance and engine life and most definitely not do any harm to the vehicle

Developing and testing additives and proving an effect that you can honestly advertise is a long, slow process.

[tuga2112]

the urban myth is really simple to explain

supermarket fuel is cheaper than branded
people who are trying to save money buy cheapest available.

vehicle maintenance is (in most scenarios) a cost that you cannot see the benefit.
people who are trying to save money avoid vehicle costs for as long as they can until its impossible to avoid (weird noise from wheel? its still spinning its ok... sometime later hub falls to bits when initially it was a straight bearing swap job)

people are not willing to accept responsibility for their negligence
supermarket fuel gets the blame.

the fact that theres regulations and inspections of those tanks and pumps on a regular basis (which were lobbied by the petrol brands) assures ME that the safety and quality of the fuel has a minimum standard that is acceptable for the government (note that the politicians also have cars... in fact cars more expencive than ours)

im confident that considering how corrupt the system is.. it actually works out to our advantage in this specific scenario.... now dont get me started on housing market... thats one where it clearly doesnt work for us...

with all that said.. i been filling up at morrisons and tescos pumps for more than 10 years. none of the problems i have encountered in my cars were anywhere near or related to the fuel delivery system of the car.

[anonymous-user]

tuga2112 said:

the urban myth is really simple to explain

supermarket fuel is cheaper than branded
people who are trying to save money buy cheapest available.

vehicle maintenance is (in most scenarios) a cost that you cannot see the benefit.
people who are trying to save money avoid vehicle costs for as long as they can until its impossible to avoid (weird noise from wheel? its still spinning its ok... sometime later hub falls to bits when initially it was a straight bearing swap job)

people are not willing to accept responsibility for their negligence
supermarket fuel gets the blame.

the fact that theres regulations and inspections of those tanks and pumps on a regular basis (which were lobbied by the petrol brands) assures ME that the safety and quality of the fuel has a minimum standard that is acceptable for the government (note that the politicians also have cars... in fact cars more expencive than ours)

im confident that considering how corrupt the system is.. it actually works out to our advantage in this specific scenario.... now dont get me started on housing market... thats one where it clearly doesnt work for us...

with all that said.. i been filling up at morrisons and tescos pumps for more than 10 years. none of the problems i have encountered in my cars were anywhere near or related to the fuel delivery system of the car.

Man connects to keyboard via brainwaves?

[RTB]

It's a diesel..... just make sure you filter the worst of the batter bits out of the vegetable oil before you fill up and you should be fine.

[Limpet]

The problem here is that the hard data to support any sort of definitive conclusion are not accessible, which is why after pages of debate, nobody has put anything concrete forward. You'd need to know statistics for breakdowns and component failures against the litres of fuel used by specific suppliers, and that data simply doesn't exist anywhere that I can think of. For fuel consumption, you'd need the results of back to back tests in the same vehicle, under identical tests, in laboratory conditions, which may exist somewhere, but I CBA to look.

I've run countless cars on supermarket petrol and diesel over the years with no ill effects, but I also service my cars to the manufacturer's recommendations. I suspect the latter has a far greater effect on performance, economy, reliability and longevity than the retailer the fuel is purchased from.

My personal belief is that there is a difference between 95RON and 97/99 RON (Super/Momentum/V-Power) that certain engines will be able to take advantage of, but beyond that, all road fuels sold in the UK meet BS EN x standards, which is an adequately rigorous test that ensures the quality of the fuel is at a level where your engine won't self destruct on the way home. My M140i sounds and feels just as happy on Momentum as it does on V-Power. If I ever strip the engine down in 100,000 miles time, I might think differently, but at the moment, nothing about the way the car drives on it comes even close to justifying the 15p per litre premium over the V-Power I used to run it on.

It's all guesswork, but octane rating in certain cars aside, I believe how you treat and maintain your car has a far greater impact on the way it drives and performs than what fuel you put in it.

[GAjon]

I’m not a scientist but did have some white paper disposable overalls once, so that’s just as good.
Now on Friday last week I went on a track day to Rockingham with my race car and took 2 ten litre cans of fuel, one V Power one Tesco 99 Ron.

In the morning I was on V power and was lifting on turn one.
In the afternoon I used the Tesco and didn’t lift at turn one.

Proving absolutely definitely scientifically that Tesco fuel is faster.

Or was it Tesco first? ?

Edited by GAjon on Wednesday 29th August 09:20

[996TT02]

RobM77 said:

As a former scientist, I'm well aware of that. However, in practise, if you do the same test for something this simple ten times and get the same result +/- <10% every single time (for example, results could be: 10%, 9.5%, 10.2%, 9.7% etc), statistically that's fairly conclusive (if there is no other plausible reason why you'd get those same results). To minimise the latter, I've measured the mpg in two different ways and guess what? same results again. The likelihood of me achieving those results by chance is vanishingly small. I've even done it for two different cars and yes, same result again. As I allude to above, my primary point was actually referring to the many tests done by others in a more scientific setting and the secondary point was how one's own tests mirror these findings. Your criticism is valid in many contexts, but not in this context - this is a very simple test of how much fuel is used per mile driven, it's not rocket science!


Edited to add: Let's be clear about this and restate what I said above in my first post: for more subtle issues such as Tesco fuel vs Shell fuel I think anecdotal evidence is indeed next to useless, especially when we're looking at reliability, rather than a simple number such as mpg. I agree with you there.

Edited by RobM77 on Thursday 23 August 11:46

Here's the problem with your testing Rob. For starters, I am not doubting your results - I will 100% take your word for them, that you noticed a 10% reduction in consumption on "better" fuel.

The problem is that you were testing, you knew it, and you possibly believed, had an expectation of achieving the result you obtained. This, to cut a long story short, would have affected your driving, even if you were not deliberately making any effort to skew the results - you were chasing the result, and since driving habits have a humungous effect on economy, you obtained it, albeit possibly for the wrong reason.

For such a casual inherently imperfect test to be worth anything at all (apart from being repeated a large number of times) the driver must not be aware of what is in the tank, and ideally nor that a test is being undertaken.