[23dft]

There seems to be an ongoing debate about whether supermarket petrol is bad for an engine or not. There is obviously a reason why the supermarket is charging less than Shell/BP/Esso, so it is reasonable to assume that they're not putting in the same level of additives that the major brands do.

Personally I normally use 'premium' grade petrol at 97+ Octane - including Tesco, who's premium fuel seems to be well regarded. But I will also use the cheap stuff if that's what's around - and haven't noticed any real difference in smooth running despite, alledgedly, my car needing to be adjusted to run on lower octane fuels.

An elderly relative had an old Escort (15 odd years back) and ran it on cheap petrol. Just before their MoT I'd give it a once over for them, and used to tip Redex down the carb inlet. The smoke this generated from all the rubbish being burnt off was phenomenal!

Is it worth paying the extra for better quality, or put anything in it and service it well?

[Snowball]

This is a recurring myth. First of all, Redex. I had petrol vehicles, before supermarket fuel stations existed. I have poured Redex through the carb., and it always produced an abundance of white smoke, so forget the supermarket fuel connection.

When supermarkets began to supply fuel, I started to buy my petrol from these outlets, and have continued to do so since I changed over to diesel so some 17 years ago. My present VW Touran has consistently run on supermarket City Diesel, mainly from Sainsbury's pumps, is now over eight years old, and there has never been a problem or any reason to suspect any downside.
My previous Touran, now 12 years old and now owned by a family member, has spent much time in France as well as England, has run on supermarket diesel both there and in the UK, and is still running perfectly OK.

Supermarkets can buy their fuels cost effectively because of the collectively massive amounts of fuel they purchase. Also, they can afford to cut prices to attract customers to continue on into their stores which boosts sales. Furthermore, under the sale of goods acts and EU directives, fuel quality has to meet stringent standards.

Still sceptical? Well, at our Fosse Park Sainsbury's, close to M1/M69 junction, police vehicles can regularly be seen to be filling up here. Considering the hard life of these vehicles, and reliability requirements, do you think the police would use supermarket fuel if there were any doubts about its qualities? When I read these spurious tales about supermarket fuels, I simply laugh at them and carry on!

[Spannerdemon]

Well put Snowball. We invariably use supermarket fuel, and will continue to do so in our new Skoda.
Unless you have some highly tuned car that needs the higher octane fuel, its always been a lot of nonsense.
To my way of thinking, if you want to use the higher octane fuel from supermarkets without requiring it, then carry on..... You've got too much money. Doesn't bother me.

[Santa]

I have seen many discussions about supermarket vs branded fuel over the years. Most people seem to have a firm idea of what is best and no argument will shake them. What I haven't seen in recent years is people insisting that their car won't run on cheapo two star petrol. Maybe it's like your GF insisting on mink, when rabbit would keep her just as warm.

Whatever car you drive you should look up the manufacturer's recommendation and use that. My Mk5 Mondy runs happily on 95 Ron (with up to 10% ethanol).

[Snowball]

I agree. One should always follow the car manufacturers' guidelines - almost invariably found in the handbook. For standard production cars, the grades at the fuel pumps are satisfactory because they have to meet DIN standards. My own VW Touran TD does have a warning in the handbook concerning bio-fuels.
It is significant, when branded fuel suppliers make claims about the advantages of any additives which promote savings in mpg., they always carry the rider that performance "depends on driving habits". To me, my take on this is that most drivers, when trying to convince themselves that a particular fuel is giving extra mpg, the truth is that they are probably subconsciously adjusting their driving habits, and the same improvement would occur regardless of which fuel they filled up with providing the DIN standards were the same.

[smudger]

I have filled my car with both supermarket and brand name petrol, and never noticed any difference at all?

[23dft]

Santa - I agree there seem to be two firm views. I sit somewhere in the middle, although I verge towards branded fuel. Perhaps I could try a month or so running cheap fuel and see if it has any effect.
Regarding your comment about cars running better on particular grades, I think that these days this is less relevant. In the days of two star or four star, the ignition timing for a different grade of fuel could only be adjusted manually. Nowadays, I believe that this is part of the function of the increasingly sophisticated computer control units, which means that the car will run as best it can on the fuel it is given.
If the 'star' system were still in use, the modern standard unleaded would I believe be equivalent to 3 star - the premium stuff is equivalent to 4 star.

Snowball - I did read in one online article a statement to the effect that modern supermarket petrol is equivalent to what was generally available 30 years ago, and that the branded stuff includes all the additives etc. Supposedly, the sales of petrol additives (Redex and the STP stuff amongst others) has fallen, as the petrol now includes it anyway.
Regarding economies of scale, surely the likes of BP, Shell have larger distribution networks than the supermarkets? That being said, your point about dragging people into the store is probably the case. I'm sure that there is a great attraction to being able to do everything in one place, including fill up, and many of the supermarkets offer pay-at-pump options for greater speed.

It is definitely a confusing debate with many opinions. I think I will have a month of buying only bog-standard supermarket fuel, compare the engine performance and mpg figures, and see if any difference emerges.

[alan1302]

Originally Posted by 23dft

That being said, your point about dragging people into the store is probably the case. I'm sure that there is a great attraction to being able to do everything in one place, including fill up, and many of the supermarkets offer pay-at-pump options for greater speed.

That's why the supermarkets can sell the fuel cheaper - it's not the only thing that they sell so can cut the profit margin on it - which is already very thin - and encourage you into the main store.

From what I understand from reading on other forums petrol at supermarkets and branded petrol stations is the same stuff from the same refinery. The only difference is the additives put in when the particular station is being filled up.

[Santa]

Originally Posted by Snowball

It is significant, when branded fuel suppliers make claims about the advantages of any additives which promote savings in mpg., they always carry the rider that performance "depends on driving habits". To me, my take on this is that most drivers, when trying to convince themselves that a particular fuel is giving extra mpg, the truth is that they are probably subconsciously adjusting their driving habits, and the same improvement would occur regardless of which fuel they filled up with providing the DIN standards were the same.

When I was a fleet manager, we were regularly offered so-called fuel saving devices. We were part of Thorn EMI which had a fleet of several thousand cars and we decided to put the claims to the test. In short, we tried six different devices on a variety of different cars and without exception they all worked. Well, it looked as if they did anyway. Of course it was a proper scientific double blind test, so we had ten of each device on ten different cars and ten dummy devices as well. Over the three months of the test, we found that the dummy devices did just as well as the, sometimes quite expensive, devices. Clearly a placebo effect.

A while later we experimented with LPG and really did find savings - in some cases dramatic savings. We discovered that some people were using company fuel in their own cars. They couldn't do that with company gas. :D

[Motman]

I notice an improvement in mpg when using top grade diesel compared to supermarket stuff in our Evoque. Also noticed it in our Freelander 2 before that but as has been said, that could be the placebo effect. One thing that is undeniable though between the two fuels is the diesel clatter that is noticeable with the cheaper fuels, particularly when the engines are cold.

[Snowball]

Based on using supermarket diesel, both in the UK and France, I am convinced that there is no significant difference.
What concerns me more is the excitement by local councils over the prospect of being able to put punitive charges on diesel owners if they dare to venture into cities. And revenue will reign over practicalities and ethical considerations.
The only fair and reasonable way to deal with the nitrous oxide problem (which I believe is being over stated to achieve effect) is to rely on natural wastage and technical development.
Surely it isn't beyond reach to develop scrubbing equipment that can be retrofitted to diesel-engine cars to obtain an earlier solving of the problem. I would rather pay for this than be penalised with a tax that raises revenue but does not actually improve air quality.
It needs to be remembered that a wide variety of vehicle use demands the power/cost ratio that only diesel can provide.
I am a caravanner, and have a 1.9-litre diesel car. To go over to petrol, it would need to have a 3-litre engine and, being my only vehicle, for the greater majority of the time I would then be driving a gas-guzzler with unnecessary power.
And motorhomes are almost exclusively diesel powered. I met a couple with an American-built motorhome that was petrol powered - and did 8 mpg. A cavalier approach to the situation could kill off a whole section of the economy to the detriment of GDP.
Sorry for the drift, but seemed worth mentioning.

[Santa]

It isn't just the NoX problem but the particulates as well. Modern diesels already have cats and filters, and many use AdBlue as well (VW's sneaky trick notwithstanding). All of this adds to the complexity of oil burning engines and as we have seen many times in this forum, expensive problems when it all goes wrong.

Petrol engines have come on in leaps and bounds in recent years as have gearboxes. I would have no hesitation in towing a large caravan across the Pyrenees with my 2 litre car with it's six speed, computer controlled gearbox.

As a society, we really must do more to clean up the air we breathe. My sense of smell is poor, but when I go into town and stand by a set of traffic lights, I can smell and taste the exhausts. For sure, buses and taxis are the worst offenders, but vans and cars beat them in sheer numbers.

It is better for cities to restrict diesel use (making taxis switch to electric would be a big step forward) than for the government to put a blanket tax increase on diesel fuel or cars with diesel engines. At least you have to option to Park-and-ride.

[smudger]

I can't help but think about how pointless all this "ommisions pollution" by us here in the U.K. doing all this, when the third world countries are pumping out thousands of tons of pollution into the atmosphere every day?............................... America seems to be dragging its heels as well, and they are one of the worst offenders? ............It seems to make all our efforts pointless really.

[alan1302]

Originally Posted by smudger

I can't help but think about how pointless all this "ommisions pollution" by us here in the U.K. doing all this, when the third world countries are pumping out thousands of tons of pollution into the atmosphere every day?............................... America seems to be dragging its heels as well, and they are one of the worst offenders? ............It seems to make all our efforts pointless really.

What's the alternative? Just give up?

It's should be about what's best for our own environment whilst talking and negotiating with other countries to improve what they do. You can't really tell other countries what they should do whilst not doing it yourself. The UK should take the lead rather than waiting for others.

[98selitb]

China, one of the worst offenders in recent decades, is now actually taking a decent stand environmentally, unlike the US.

[Snowball]

In reality, the only way forward is for governments to put pressure on manufacturers of pollution-causing infrastructure to use technology to its fullest ability to resolve issues, and for governments to promote the positive gains without adversely 'tilting' the economy. A sensible time scale needs to be put in place. Just punitively taxing diesel cars will not make the problem go away - financial constraints will force owners to continue to operate them, and the extra expense will force owners to take longer tp upgrade than might otherwise be possible. No brainer, really!
Two things worry me - (a) the overstatements by environmental lobbyists and (b) governments taking knee-jerk responses.

For example, the government have indicated an impending action regarding diesel cars. But they seem not to have considered diesel buses, diesel HGVs or diesel-electric trains. Because of the great difference in mpg between cars and large commercial vehicles, I would bet that cars in isolation produce less pollution than heavy commercial traffic. Also, because heavy commercial vehicles have longer lives than most cars, these more fuel-hungry vehicles have the majority of older, pollution-causing engines.

[Santa]

Diesel buses are a problem I agree. Diesel lorries on the other hand are very strictly regulated. London has the LEZ (Low emission Zone:

The LEZ covers most of Greater London. To drive within it without paying
a daily charge, your vehicle must meet certain emissions standards that
limit the amount of particulate matter coming from its exhaust. Particulate
matter is a type of pollution which can contribute to asthma, heart and lung
disease, other respiratory illnesses and even early death.

The EU has been driving standards up for years and new regulations (for instance the latest lorries can't be left idling for more than a few minutes) are pretty stringent. The railways are switching to electric power as fast as they can, and there are new regulations about leaving engines running when not actually moving.

I am not so sure that hauliers keep lorries longer than private car users either. The vast majority of lorries that you will see on the road are under five years old. Hauliers want to be seen as smart and up to date, as well as running the most efficient vehicles. Many of them lease their trucks for a five year term.

Lasltly, I fail to see any kind of "knee jerk action". These changes have long been heralded and there is nothing much going to happen in the short term.

[wagolynn]

The manufacturers will not make changes unless they are pushed.

Look at what happened with the most recent EU regulations for diesels, the manufacturers agreed, and were given plenty of time to develop solutions (I think about 10 years) but when the regulations were to come into force they went back, and said it was not possible to meet them.

It is possible but it will add cost, and they fear that people will just stop buying diesels which in a way solves the problem.

In the short term I think the way to go is direct injection petrol with turbo charger. This gives high torque, relatively flat torque curve so reducing the need for many gears, and good fuel consumption.

This would bridge the gap until practical batteries are developed or a way of producing Hydrogen which is both, economical, and low emission is developed.

[Santa]

Originally Posted by wagolynn

The manufacturers will not make changes unless they are pushed.

Look at what happened with the most recent EU regulations for diesels, the manufacturers agreed, and were given plenty of time to develop solutions (I think about 10 years) but when the regulations were to come into force they went back, and said it was not possible to meet them.

I do not follow this. We are currently in the sixth stage of EU regulations. This is what the VW scandal was all about - them trying to sidestep the rules.

Euro 6 is the sixth incarnation of the European Union directive to reduce harmful pollutants from vehicle exhausts. The Euro 6 standard was introduced in September 2015, and all mass-produced cars sold from this date need to meet these emissions requirements. The aim of Euro 6 is to reduce levels of harmful car and van exhaust emissions, both in petrol and diesel cars.

This includes nitrogen oxide (NOx), carbon monoxide (CO), hydrocarbons (THC and NMHC) and particulate matter (PM), which is basically soot from diesel cars. The knock-on effect of reducing these pollutants can also mean improved fuel economy and lower CO2 emissions.

[23dft]

Supposedly, TfL are mandating that all buses in use in central London will soon be hybrids. I know somebody who works on the buses and they apparently have certain routes where the hybrid buses must be used. Apparently, the way the contract is set up, if one of the hybrid buses breaks down and the only substitute is an older diesel bus, it is less hassle for them to simply cancel the journey than it is to put the older bus on.

Delivery vehicles are certainly something which should be looked at, and I know that some electric vehicles are now being used. One of the things which strikes me as odd is the plethora of companies operating in this sector. Our loading bay at work will see a Transit pull up from one firm, deposit five parcels, then go. Ten minutes later, another Transit from a different firm appears, dropping a couple of parcels off. In total, there may be a good 20-30 deliveries from small couriers per day - none especially time sensitive. Could traffic (and emissions) not be reduced by couriers having set areas they deliver to, thereby making better use of their fleet?

[Santa]

Originally Posted by 23dft

Delivery vehicles are certainly something which should be looked at, and I know that some electric vehicles are now being used. One of the things which strikes me as odd is the plethora of companies operating in this sector. Our loading bay at work will see a Transit pull up from one firm, deposit five parcels, then go. Ten minutes later, another Transit from a different firm appears, dropping a couple of parcels off. In total, there may be a good 20-30 deliveries from small couriers per day - none especially time sensitive. Could traffic (and emissions) not be reduced by couriers having set areas they deliver to, thereby making better use of their fleet?

An old hobby horse of mine. I used to do collections and deliveries around Birmingham for Palletforce. There are four or five similar companies all in competition with each other and I would see all of them many times a day in the various trading estates we served. With parcels, the problem is multiplied several times over.

The problem is that all these companies are in competition with each other on price and quality. Add to this that the company I worked for handled a lot of Irish groupage, and most of the competition did not.

[Sighn]

Sainsbury's BP

Sainsbury's obtains fuel out of BP tankers; they're seen within Sainsbury's petrol stations yet I never see anyone make any real comment about this prior to insisting that supermarket fuel is, without doubt, worse than the branded. Surely this means that whatever additives you'd find in a BP station is exactly the same as what you'd get in Sainsbury's.

The only way I could imagine that they're of different quality is if aforementioned BP tankers only attend Sainsbury's stores before going back to the refinery.

[wagolynn]

Well, yes, and no.

Some additives are put into the petrol as the tanker is loaded, the British Standard does not include additives.

The basic fuel is to British Standards, the questions becomes, do supermarkets pay for the additives?

On balance I think most of them do, as the cost of the additives is relatively low.

Diesel without the winter anti-wax additive would be unusable, in modern diesels, in cold weather.

[Sighn]

Surely, if a BP tanker is seen at sainsbury's, that supermarket is using BP fuel and therefore BP's blend of additive.

[Santa]

Not necessarily. The additives are added when the fuel is loaded into the tanker. At the depot, you can see all the different companies queuing up to load from the same source.

As well as that, a tanker can have as many as five compartments - each of which may contain different fuels.

[Sighn]

Ahh.. Makes perfect sense now, thanks.

[smudger]

Speaking of fuel, that TV advert for BP, where they say their fuel can clean the engine and give you an extra 20 miles from a tank...........................any truth in that?

[Beelzebub]

Originally Posted by smudger

Speaking of fuel, that TV advert for BP, where they say their fuel can clean the engine and give you an extra 20 miles from a tank...........................any truth in that?

They can't advertise something if it isn't true. In practice, this means that if someone raises a complaint with the Advertising Standards then BP would have to be able to substantiate the claim.

Since anyone (including competitors, and indeed your good self) can raise the issue, I imagine BP must be pretty confident of their claims. (Or at least of their ability to bamboozle the ASA).

[Santa]

Originally Posted by smudger

Speaking of fuel, that TV advert for BP, where they say their fuel can clean the engine and give you an extra 20 miles from a tank...........................any truth in that?

An extra 20 miles on a £60 tank of fuel is not a lot. If it didn't work for you, they would blame it on your driving.

[wagolynn]

It is possible to improve combustion two ways on a modern engine, the first is to clean out the injectors which in most cases will give better atomisation of the fuel, and therefore better cleaner combustion with more of the fuel being burned in the engine rather than in the cat.

If the inlet valves are cleaned as well this will slightly improve breathing with a small increase in power.

The other route, is to improve the combustion it's self, this is usually done by using an additive that adds oxygen or one that catalyses the oxidation of the fuel.

However, if you give most drivers extra power they will just use it, which will cancel out any improvement in mileage from the additives.

Short of putting an engine on a dynamometer. it is difficult to prove a small power increase, and just as difficult to prove no increase.