Whether you use supermarket fuel, branded unleaded petrol, diesel, or one of the “super” fuels, the chances are you’ve sometimes wondered about the quality of the liquid you’re feeding into your vehicle.
Our recent survey, conducted towards the end of last year, certainly raised many queries from members regarding fuel quality, especially in reference to the differences between supermarket and “name brand” petrol and diesel. Many of you were also very curious about the real-life benefits of paying extra for “Super” fuels instead of sticking to the cheaper standard options.
In response to the hundreds of queries we received, we decided to help out and find you some answers, based on in-depth research and expert opinion. While we suspect that some of our findings may prove controversial, we hope we’ve managed to distil the current “conventional wisdom” on these issues – so read on to find out more.
How we approached our study?
When we sat down to discuss this study, one of the PetrolPrices.com team pointed out that he had a friendly scientist in his extended family – a specialist in biochemistry. Speaking to him seemed a good place to start.
He told us that fuel science is essentially centuries old and very well researched, and was able to point us to some good sources of information. He also provided us with his own view on the controversial topic of supermarket fuel – so let’s start there.
Supermarket Fuel vs. Branded Fuel
Our friendly scientist was very clear on his view regarding supermarket fuel. He said the following:
In the UK, all pump gasolines and diesels are governed by various national and international standards – notably European and CEN Standards. These require vehicle fuels to conform to minimum world-agreed quality and performance standards… so in Europe, supermarket fuel is as good as any.
We can already hear the sharp intake of breath from some readers, because this is a fiercely debated topic. Just look at any article or forum thread on the subject and you’ll hear people passionately arguing that supermarket fuel is inferior.
We were curious about just how common this view was amongst UK drivers, so before completing this article we carried out a quick Facebook survey asking whether people think supermarket petrol is inferior. The results of our survey suggest that around 40% of drivers really do suspect that there is something “less good” about supermarket fuel.
However, our friendly scientist is far from alone in his opposite opinion. A recent study in The Telegraph on the same subject cited spokesmen from both The RAC and The AA saying much the same, with the AA representative stating that “petrol and diesel fuel quality is governed by the same European standard, whether it is sold at a supermarket in Manchester (or) an independent outside Mevagissey.”
This seems pretty conclusive, and is backed up yet further by plenty of anecdotal reports online from consumers who have witnessed supermarket and name-brand tankers both stocking up at the same places.
However, there is a little more to this. As explained in a report in The Express, all petrol and diesel is made up of a base fuel and an additive mix. The additives the supermarkets and the various other brands choose to use will not necessarily be the same. The differences shouldn’t be significant enough to effect fuel economy or the “quality” of the driving experience, but this factor could have some part to play in the fact that some individuals are utterly convinced that supermarket fuels are in some way “different.”
This aside, we have to conclude that there is absolutely no scientific basis on which to assume that supermarket fuel is “bad” or unsafe. Around half the fuel powering the cars on Britain’s roads, right now, came from supermarket pumps – so if there was something wrong with it, we’d know by now. Even so, we’re ready for the inevitable debate!
Super Fuels vs. Premium / Standard Fuels
The other big question our members asked when we conducted the survey was what the real difference is between standard fuels and the “super” versions we see on forecourts for more money. At the time of writing, these come in at around 10 to 12 pence per litre more – so choosing to use them instead of their standard equivalents is a fairly pricey decision.
The first matter to clear up is any confusion between “premium” and “super” fuels. Standard 95-octane unleaded petrol is sometimes called “premium unleaded,” so we mustn’t confuse this with the more expensive “super” fuels, which are 97, 98 or even 99-octane.
Some examples: BP offer “Ultimate” unleaded, Esso call theirs “Synergy Supreme Plus,” and even Tesco have a “super” petrol of their own called “Momentum 99.”
So, do these fuels make any difference to how your car runs?
It seems that in many cases, the answer to this question is indeed “yes.”
We had a look in the instruction manual for one of the PetrolPrices.com team’s car – a 2.0FSi Seat Leon. The manual actually specifically recommended using “Super” unleaded, at 98-octane. It turns out that many car manufacturers make the same recommendation, especially when it comes to performance cars.
Let’s look at the science: The octane rating of petrol (or the cetane rating, in the case of diesel) describes how efficiently a fuel burns when used in a combustion engine. The higher the octane figure, the higher the efficiency. As per this report, a higher number can mean better performance and / or better fuel economy – though whether you’ll notice it on your daily commute will depend much on your driving style, your vehicle, and your attention to small details!
The octane or cetane ratings are not the end of the story. “Super” fuels also usually come with a more “luxurious” additive mix to deliver better performance or economy. For example, Esso’s Synergy Supreme Plus contains “double the detergent additive” compared to Esso’s standard fuel. Shell’s V-Power Nitro+ Unleaded apparently forms “a protective film on metal (to help) prevent corrosion.”
Once we get down to these additives, it’s all a little like comparing shampoos and toothpastes. There are probably some motoring enthusiasts who swear by a particular brand for a particular reason. However, the octane or cetane rating of a fuel is a more scientifically relevant way of comparing “standard” to “super.”
So should you use “super” fuel in your vehicle? Well, we’d suggest looking in the manual for your car to begin with, just like we did. If your manufacturer points you in the direction of high-octane fuel, you may want to stick with their advice.
However, unless you have a performance car or a “hot hatch,” you’re probably fine to stick to the standard stuff. This is a view supported by Matthew Minter, the Editorial Director for Hayne’s Maintenance Manuals, who says that “99% of cars will work perfectly well on 95-octane standard unleaded fuel.”
If you choose to defy the advice of your manufacturer, it has to be your own decision. For what it’s worth, that Seat Leon we mentioned above has worked just fine with standard 95 petrol, but our inclination is to go with the manufacturer’s advice – particularly as there is science to back up the use of higher octane fuel.
What About Fuel Additives?
Another option open to you is to use a third-party fuel additive such as Redex. These often claim to improve both performance and miles per gallon, and are an inexpensive “treat” for your car.
Essentially, these products perform the same kind of function as the additives in “Super” fuels – primarily keeping engines clean and lubricated.
However, as far back as 2009, Auto Express reported on a Which? study that described such additives as “a waste of money.”
There are sure to be some drivers and mechanics who use and trust these products, but the science doesn’t seem to agree. One thing Auto Express seemed very clear on is that they certainly don’t offer any kind of octane boost to rival that of a “Super” fuel.
Supermarket Fuel and “Super Fuel” – Our Conclusions
Our research into these fuel quality questions has produced some fairly clear answers. However, we suspect, based on the voracity of some of the motoring enthusiasts who frequent the forums, that plenty of people will still debate our findings.
In brief, our research throws up the following conclusions:
- There’s no scientific evidence to suggest that supermarket fuel is inferior to its brand-name equivalent.
- There are some proven benefits to using more expensive “super” fuels, but these benefits are only really pronounced in sporty vehicles.
- Third-party fuel additives don’t seem to stand up to their bold claims when tested. However, some people state additives work well for them. You could try them for yourself to see if they make a difference, as they cost just £5 a bottle so may be worth trying – if only once!
I drive a MK4 Golf GTI 1800 turbo 180bhp and up to recently I used Sainsburys normal unleaded.
After reading the handbook to check something I noticed that VW recommend higher RON for this engine, so gave it a go. Filled tank with Super and the difference was vast, it was really better, smoother, better throttle response,more willing to rev. All round improvement………..
The premium petrol not only has higher knock resistance but it burns in a more sustained way. That means rather than the piston crown effectively being dealt a hammer blow, they are being pushed downwards.
As your engine is new enough, it would benefit from a remap which you could have specifically for higher octane petrol. You could still use regular petrol though as your engine will have knock sensors. These are not there to protect the engine but to retard the ignition to lower the production of oxides of nitrogen (NOx) which happens before maximum permissible advance is reached.
The upshot is a good remap from someone who specialises in Volkswagen remaps (see owners clubs or forums) would produce more power, better driveability and better fuel economy even for an engine designed for high octane fuel. I wouldn’t say it was essential though and it would produce less improvement from a smoothness point of view than the switch to 98RON yielded.
I think your description of the octane/cetane rating is misleading. Efficiency suggests a relationship between the fuel input and the energy output. The octane and cetane ratings actually relate to the reluctance of a fuel to detonate; the higher the rating, the more compression the fuel can withstand without combusting. This is the reason why manufacturers recommend a higher octane rating for high performance cars – because they often have a higher compression ratio. Using a lower octane rating may result in ‘knocking’ or pre-detenation.
I have until recently always filled up my car at the local Tesco garage. About 3 weeks before Christmas I filled up with Jet petrol as I needed petrol and I was near the garage. It was more expensive. That week I did my normal journey and half way through the week I thought my gauge was broken as I had only used half a tank of petrol usually would have used 3/4 tank. Filled up as usual in Tesco and thought nothing of it. Until just after Christmas I filled up at Sainsbury’s and again the petrol lasted me almost twice as long. I went to Sainsbury’s again the following week, and now will never go back to Tesco. Their petrol is obviously on poorer quality.
Can we be clear about the role of additives please? Certainly, all fuel sold in the UK (whether a premium brand or a supermarket fuel) has to meet a minimum standard, Does that standard calibrate simply the quality of the fuel alone or the combined quality of the fuel plus additives? If the latter, then surely there are two questions. 1. Is it worth paying for higher octane (petrol) or cetane (diesel) rating if the handbook does not specify this? 2. Is it worth paying for supposedly better quality additives or not? If the additives in even cheap, own-brand fuels keep the engine clean through their detergent effect, is there evidence to suggest that the extra detergent power of super fuels also removes previously-accumulated grime? Shell’s marketing suggests that it does. It would be useful to know whether any such additional detergent benefit is derived from constant use … or whether periodic fill-ups with super achieve the same effect?
I don’t agree with the biochemist’s conclusion. I know my own car runs better on branded fuel and even my sister can tell every time whether her car is running on Shell or not. Seriously and that is only by sitting in the passenger seat.
There used to be good reason not to buy supermarket fuel but now it seems even branded fuels contain alcohol based ethanol rather than pure petroleum methanol. Bio diesel is no better either. Ethanol separates and turns to water. It goes off much faster too. My experience with a bus company suggests that biodiesel jellifies readily when the temperature fluctuates greatly around zero degrees. It blocks fuel filters, causes driveability issues, brings on the MIL indicator and is probably the greatest cause of breakdowns. It also means the fuel filters must be changed far more often than the manufacturers service recommendations.
My guess is that Fubra will not support this. After all, they readily support Greenergy who brought us the rubbish biofuels in the first place. Unfortunately, I believe that there is probably no way to avoid fuels with bio content due to lower taxation. However, engines run worse, they cause internal corrosion and cause often necessitate increased servicing costs.
As a side to that, I believe the premium fuels do not contain bio matter. That is precisely a reason to use them if the engine benefits. If it doesn’t, then in the case of a petrol engine, a performance remap to take advantage of the extra knock resistance is a good idea. It is a good idea anyway as these fuels have a more sustained pressure on the piston crown which anyone with even slight a engineering grasp will realise is a good thing.
As a side to all this and I state I am in no way connected with Shell or any part of the oil of petrochemical industry, nor indeed do I have shares in such, I did notice during mg years as a mechanic that the cut price dealer serviced cars had much dirtier (gum and varnish) engine internals than specialist or reputable independent serviced cars. There was also a greater chance these cars inflicted with cut price servicing were the ones which needed major engine repairs. Again my belief on that is often attributable to poor quality fluids which do not do what the are meant to especially with regard to internal corrosion protection.
I have a motorhome and I keep a record of the mpg I get every time I fill up. Clearly there are a variety of factors that will affect mpg including the prevalent wind, the types of roads being driven and the nature of the terrain (i.e. flat or hilly). I normally use branded diesel and I average 28.9mpg; this being over 25,000 miles. A couple of years ago whilst travelling in France I thought I would try supermarket fuel to see if there was a difference. Within 2 fuel fills my economy was down to 25mpg and I reverted to branded fuel and within 2 fills my economy was back up to 29mpg. Last year I was again in France and tried using premium fuel (it is only 4c a litre more than standard fuel). After about 4 fills I found it was making no difference whatsoever and reverted back to standard fuel.
Likewise with petrol. A few years ago I had a scooter and again I only used branded fuel. One day I was getting low on fuel and the only available source was a supermarket. I filled up and set off and within a few hundred yards my wife, who was riding pillion asked what was wrong with the scooter. It was the supermarket fuel. It took 2 refills of branded petrol before my scooter was running smoothly.
The safest bet is to spread the risk and use all fuel brands, oil brands, oil filter brands. If one brand is deficient in some way it will be averaged out and unlikely to cause an issue over the life of the car.
Surely it would have been more beneficial to speak to an expert in petrochemistry rather than “a specialist in biochemistry” for this study??
I have a 2010 Toyota Rav4 diesel and I have stopped using supermarket fuels as there is definitely a difference. I have been monitoring fuel consumption very carefully over the last year, by use of the onboard computer and by doing brim to brim calculations. Firstly, taking into account the variables, using Shell or Esso, consumption is improved by up to 3 – 4 mpg – it will drop whenever I use a supermarket or one of the cheap brands; secondly, I notice a definite improvement in smoothness and engine noise when using the more expensive ultimate blends. When I filled up at the village service station, which has some mickey mouse brand I had never heard of, the car became noticeably agricultural. I belong to a SUV forum and the general consensus of opinion is that supermarket brands are definitely inferior. An additive called Millers seems the favourite and I shall be trying it when I have used up my stock of Redex. Just a bit more boring information – I know someone who will travel miles to buy the cheapest diesel and will not used additives. He has just forked out over a grand for a new set of injectors – an isolated example perhaps, but I rest my case and will continue to use Shell with one fill up every four of the V power or whatever name it goes by.
I recall being instructed not to use fuels from Morrisons or Tesco a few years ago. Is there a suggestion standards have improved since then?
There is a difference in consumption when I have used Tesco’s petrol as against Sainsbury’s Petrol with Sainsbury’s coming out slightly better! I also tried Tesco’s Higher Octane against their regular. There was a difference in consumption, but calculating it out per mile it worked out about the same
Speaking to a biochemist about fossil fuels is like speaking to a florist about a dental problem. It is completely barmy.
Sorry to double post. Modern petrol engines have sensors to advance the timing (increases power output) until ‘pinking’ would just start to occur. Pinking is uncontrolled detonation of fuel and is a bad thing. The higher the octane the further the ignition system will advance the timing and in theory lead to a higher power output. All petrol engines have this system as far as I am aware and not just ‘hot hatches’. There is no such feature in diesel engines.
I recon to get between 5% and 10% better mpg when using Shell Standard Diesel than Tesco which is 3% cheaper. Can’t you do a rolling road test to take out the road, wind and driver conditions?
I have a ten year old Hyundai Getz that I have run on supermarket fuel from new. As an experiment, I tested my MPG on a mostly motorway/dual carriageway run I do nearly every week.
With supermarket fuel the best I got was 38.3 over several weeks. I then filled up with Shell Premium and it felt almost instantly to run more cleanly.
In the following couple of weeks I have achieved a maximum of 41.8 on the same route, so there is definitely something in it.
I’m converted for now, if the price fluctuates too much I would switch back
Whilst you may be OK with supermarket petrol, save for a little loss in performance, there is no doubt whatsoever that supermarket diesel is a case of getting considerably less than what you’ve paid for. There are many apocryphal tales about for sure, but there is also a myriad of evidence from within the motor trade, linking fuel line, injector and other issues, directly to cheap supermarket diesel.
Have been using Esso and Shell super brands in my classic cars and find they run better for
it.
They are a 1965 Humber Hawk and a 1968 Wolseley Hornet.
My 1.9 Citroen ZX leader diesel ran perfectly well on Tesco fuel.
Tesco, cooking oil I might add.
I kid you not.
ASDA diesel has no detergents and the wax deposits clog up your fuel filters……….stay clear!
Well iv been using sainsburys diesel for the last 3 weeks in my Insignia ,and kept getting Diesel clatter when driving off especially when cold ,so as an experiment I ran the tank down then filled up with BP diesel , and believe it or not there is no clatter apart from a but when engine is cold ,so it worked for me and I shall be using BP fuel from now on
Interesting debate!
Personally I spend £500-£600 a month over my two recent model ‘E’ Classes….and feel that by getting between 50>64 mpg [from 2.1 ltr diesel engines], from 100% supermarket fuel (95% being from Tesco), I really do not believe I am getting a bad deal.
I have an ex-motor trade friend who would never use supermarket fuel; normal reasons …compounded with the fear “of Tesco taking over the world” type attitude!!
This sdide…I wonder how much fuel the air filtration unit’s – aside of the pumps, on virtually all forecourts – actually return from vapour, fuel back into their main filling station tank…and re-sell!! Is that adebate for another time??
I run a 1.6dci Renault Scenic. I had the previous model before a 1.9 dci, which pulled from low down revs. The newer 1.6 is a great engine but suffered low revs, had to be careful pulling out in second gear below 1300rpm and generally lethargic at lower revs. The point of this is that that was on supermarket fuels. With Shell (especially) and BP their standard fuel makes a crucial difference, to me there’s more bang. The V Power/Ultimate fuels seem to make the engine smoother still but the price difference, is it worth it.
I’m converted, supermarket fuel only if I have to, there maybe variable quality out there, but I convinced the additives in Shell/BP/Esso make a difference and matter to me with my style of driving, with the knowledge the engine maybe being looked after better too
I have been adding 2stroke oil to my diesel for the past two years as I drive a 2002 audi TDI and a 2005 Audi A2 the 2stroke replaces the reduced sulphur content of the diesel that lubricates and cleans the system the results a quieter running engine and 10% improvement on fuel consumption both using sainsburys standard diesel.
This trial i did after reading that Mercedes often add 2stroke when using inferior diesel when carrying out trials abroad. I use only semi-synthetic super 2stroke from esso or mobil service stations, it can also be obtained on the internet at half the price. 150ml to 45 liters does the trick.
I’ve owned so many cars from basic Fiat Punto to my favourite Honda NSX. I tried all fuels from different stations and set the mileage counters every full up. Not any difference could I find between the fuels used in any car basic out sporty. I choose the cheapest every time. That’s my own test however I still speak to taxi drivers that swear paying more per liter is better for them.
Additives from established makers liken Redex claim to “clean” the fuel system, not boost power. It removes carbon deposits. By merely cleaning a system you boost the power. In a clean system it does nothing. This was not mentioned in the article. Some more expensive petrols do have a higher octane, but some have more detergents, the sort in Redex. For those who think Redex is snake oil Toyota also make a an engine cleaner that you pour in the fuel tank every 5,000 miles.
So, what is the best petrol to pump in the tank that keeps your fuel system clean? The article never covered that. I use Redex every now and then especially before taking the car for an MOT.
I was given a complimentary ride home by a Taxi firm based in Manchester paid for by a car servicing company (possibly the largest taxi firm as they have contracts with many major firms) and the taxi driver told me that his boss (a multi millionaire) would instantly sack any drivers using his cars claiming fuel from any supermarket as “the fuel is inferior and would lead to damage to his cars and result in lower second values”.
Refer to “stompie” comment. I drive a 14 month old e220 with 61k on the clock. Only driver from new. Working for a prestigious London chauffeur co. Properly serviced. Average mpg between 52 & 58. This includes central London driving in peak times. I only use Tesco Diesel. Problems NONE
I have a mercedes diesel 220 and I fill up at shell reason is the wife noticed the difference i filled up one tank from the supermarket and she complained the drop in power or responsiveness of the car.So I filled up with shell diesel
and she’s happy btw I didn’t tell her the diesel was from the supermarket but she knew………… So now it’s shell standard or or shell nitro diesel…..
Car :VW Golf GT 2.0 TDI MK7 manual. Worst performance in my personal experience ASDA. Next Best Esso or BP. Best, Shell Standard. Night and Day at least from my particular fill up station. Like a pocket rocket with the Shell, with hardly any turbo lag. Almost as much fun as a 2.0 petrol without the jaw dropping fuel bills.Don’t know if it’s down to additives or if the fuel itself is of a different quality? Surely fuel grades are regulated?
I run a Smart Forfour Brabus and use 98 octane unleaded as recommended by the manufacturer. The car runs better and achieves slightly better MPG over standard unleaded, but the difference is marginal.
To off-set the increased cost per litre, for the last 2 years I have cycled for all journeys of 10 miles or less. After the initial outlay on proper clothing for all conditions and pannier bags to get my shopping home, I have dramatically reduced my spend on fuel and maintenance, lost over a stone in weight, feel (and look) much better and have no parking problems. On top of that, I may even have saved a Polar Bear!
My 2004 corsa 1.4 has its fair share of power, but this falls of after a while. I have found that adding redex to the tank now and again makes a difference, and if I do it just before a long run after about 30 miles I can feel the difference.
Its not just me I have used it without telling my wife, and she always says that she notices he difference.
Years ago I would use redex to clean the carburett’er and it would wipe off the varnish like deposits so easily.
Its worth a try.
Have owned a late 2007 Seat Leon FR diesel since it was 6 months old. Less than 1000 miles after we bought it, the DPF clogged up and Seat dealer had to do a DPF regeneration. As a result, we started to use Shell V-Power Diesel and whilst the MPG only increased very slightly, the engine feels smoother and perhaps a tad more responsive. On 2 separate occasions several years ago, we had to fill the tank with standard diesel as we couldn’t find V-Power (or BP Ultimate as a fall-back) diesel when on holiday in Cornwall. BOTH times after we returned from those holidays, within days the DPF had clogged, the DPF filter warning light came on & despite following all instructions to try to get the engine to self-regenerate, the car had to go back to Seat for them to “force” regenerate. Thankfully V-Power availability in Cornwall is much improved, so our holidays no longer give us car worries! Coincidentally, 2 weekends ago we felt the car perform a DPF “self” regeneration (fairly intense heat in car cabin coming from front end & slightly lumpy engine for around 20 minutes on high speed road), so we know it’s capable of DPF self regeneration IF the filter’s not too badly clogged by using standard diesel…
Also, SEAT did a recall on this particular model to replace the diesel injectors due to a design flaw. We had it serviced at the same time and when I went back to the dealer to collect the car (50k miles on it at that time), their chief tec. came through to reception to ask me which diesel I used. I was worried & asked why he wanted to know & apparently, he & another tec. were very impressed with how clean the original injectors were & how smoothly the engine ran when the car was road tested. That proved to me that paying the extra per litre was well worth the cost!
I run a small transport business & for the vans always buy the cheapest available diesel. HOWEVER, I add REDEX diesel treatment virtually every time I refill. Depending on which van, I have never experienced DPF issues and have only ever had to have one EGR valve replaced (on a van I bought second-hand with 70k miles already on it), so compared to other contacts in the industry that run similar vehicles, my vans do seem to experience fewer fuel system/exhaust management related issues & therefore cost me less in “down time” and repairs, but of course at the expense of REDEX at around £2.49 + VAT per 500ml if it’s on special at COSTCO or around £3.00 + VAT per 500ml if not on offer. Since vans have bigger diesel tanks than cars, one 500ml bottle of REDEX treats around 3 refills whereas a car would get around 4 refills.
I worked for 20 years at an oil refinery as a fuel analyst, Petrol is all very much the same as one brand to
another. “Super” fuels are higher octane which will benefit high performance engines which run at high
compression ratios or turbo etc boost.
“Redex” and the like are high performance lubricants. They can assist with keeping valve gear, valve stems etc
clean. “Upper Cylinder Lubricant ”
I remember a pal a long time ago with a old Ford V8 Pilot….very knowledgeable with engines.,
“running a bit rough……some valves sticking” put a couple of gallons of petrol plus a “Long” shot of “Redex”
and 200 yards down the road it cleared its throat and went like stink as the valves “unsticked” also
good medicine for piston rings.
I put “redex” in my CitiGo and keeping a log of mileage on a full tank to full tank I think see an improved
mpg of about 1-2% but it is difficult to be objective bearing in mind all the other variables like traffic
weather, temperature barometric pressure etc.
Perhaps you just drive better when you have given the car a treat ?
Hello David,
Thanks for your article. It made the difference and I have to agree with you on the weather, temperature barometric pressure etc. traffic etc.Before the Mulitronic A4 TDI I had a 6 speed manual version. Had I chose the right time and cruised at 70 Mph without overtaking HGV’ s I know I would of bettered my MPG. There something in that hot stuff that makes the difference. I had one DPF event in my manual car in two years. I’ve had none in this one because the Mulitronic gearbox speaks directly to the DPF via the engine management. Its just increases the revs and cleans it out before I need to take drastic action.
Again Many thanks the Car runs like a dream!!
Regards
Nigel Henry
Hi Nigel, just wondered how you can drive at 70 mph without overtaking any HGV’s ?
My last job was working for a fuel storage company, and I can confirm that all fuels in the UK come from exactly the same storage tanks. The additives are added later by the companies, but the base fuel is exactly the same.
As far as diesel additives are concerned, I’ve seen a number of tests that show that Millers Diesel EcoMax significantly improves performance and fuel consumption, if used regularly. The others are pretty much a waste of money.
I have a 2015 Audi A4 TDI 150 Bhp. Only 11000 miles on the clock. I always used the cheaper supermarket diesel.After reading your articles and looking at Audi’s recommendations, I tried the Shell V Power diesel.
I took a 450 Mile round trip up north. It was more responsive and it was smoother and definitely more powerful. The revs do not lie.I was wondering why I am overtaking slower cars like they were standing still and still basically doing 2000 revs?.I done 211 miles on a quarter of a tank. I cleaned the exhaust while I was up north, it was black and sooty. When i got home it was light black.
Its done its job in cleaning out the engine.There’s definitely something about the hot stuff. The extra detergents in these fuels are definitely a factor, especially in these newer cars.
My conclusion is:-
If times are hard, use the cheap stuff. But occasionally, give your car a treat. Its beneficial. Is it worth the extra 10 pence a litre…… Yes
I’m converted now
Id like to call BS on this article.
The whole ‘no evidence to support 911″..sorry “supermarket fuel is inferior” is a pointless statement when time after time, DIESEL users especially see a difference immediately from the extra cetane… then, long term they see benefits of the cleaning THIS IS ULTIMATELY NEVER TESTED on TV programs/youtube and the like
They never take into consideration the
a) MPG benefits LONG TERM
b) the cleaning of the engine LONG TERM
c) the quietness of the running of the engine (and day to day living with rev drops), and in cold weather
d) They use new, clean cars opposed to a ten year old gummed up vehicles that will show the benefits
e)They don’t use 5 tanks worth, just a single one and measure BHP increase
f) The amount of soot given off which will kill EGR and DPF filters
In all these tests, with the ECU having time to learn the new cetane levels, will make perfectly obvious a difference in the quality to a driver who is experiencing this first hand.
As far as I an see, no REAL WORLD test has EVER been done, just one off, single tank, bhp figures
Petrol, Ive only ever felt was a boost in octane rating from premium fuel, and so it drives lovely on the v6 and slight better mpg but not enough to justify. Diesels on the other hand you really have to do your homework and test various fuel stations (and time of the week/day) as they are DIRTY and have lots of failure points.
Quote “In the UK, all pump gasolines and diesels are governed by various national and international standards – notably European and CEN Standards. These require vehicle fuels to conform to minimum world-agreed quality and performance standards… so in Europe, supermarket fuel is as good as any.”
A completely illogical statement – yes they all meet a minimum standard, but how does that translate into “they are all equally good”?
Maybe they are – but the fact that they all meet the same minimum requirement doesn’t prove it. You need a new friendly scientist.
Good point.
I recently part exchanged my x type jaguar 2.0 diesel sport with 203,000 on the clock still on original injectors and fuel pump and every single tankful was ASDA diesel (i live less than 150yrds from an ASDA selfservice 24hr forecourt. Ran like a dream. Had injectors calibrated at 29,000 miles and did not touch them again.
For goodness sake just try a couple of tank-fulls and draw your own conclusions. Simples! My cousin recently tried Esso’s jungle juice in his humble Punto Evo 1.4 and was truly taken aback by the improvement …and he’s a mega-tight yorkshireman! Always used V Power myself. Small (warm hatch) turbo engine suitably benefits/do less than 6k a year, why on earth use a lesser fuel? Simply read up ‘Honest John’ on the subject. End of story!
I drive a MK4 Golf GTI 1800 turbo 180bhp and up to recently I used Sainsburys normal unleaded.
After reading the handbook to check something I noticed that VW recommend higher RON for this engine, so gave it a go. Filled tank with Super and the difference was vast, it was really better, smoother, better throttle response,more willing to rev. All round improvement………..
The premium petrol not only has higher knock resistance but it burns in a more sustained way. That means rather than the piston crown effectively being dealt a hammer blow, they are being pushed downwards.
As your engine is new enough, it would benefit from a remap which you could have specifically for higher octane petrol. You could still use regular petrol though as your engine will have knock sensors. These are not there to protect the engine but to retard the ignition to lower the production of oxides of nitrogen (NOx) which happens before maximum permissible advance is reached.
The upshot is a good remap from someone who specialises in Volkswagen remaps (see owners clubs or forums) would produce more power, better driveability and better fuel economy even for an engine designed for high octane fuel. I wouldn’t say it was essential though and it would produce less improvement from a smoothness point of view than the switch to 98RON yielded.
I think your description of the octane/cetane rating is misleading. Efficiency suggests a relationship between the fuel input and the energy output. The octane and cetane ratings actually relate to the reluctance of a fuel to detonate; the higher the rating, the more compression the fuel can withstand without combusting. This is the reason why manufacturers recommend a higher octane rating for high performance cars – because they often have a higher compression ratio. Using a lower octane rating may result in ‘knocking’ or pre-detenation.
I have until recently always filled up my car at the local Tesco garage. About 3 weeks before Christmas I filled up with Jet petrol as I needed petrol and I was near the garage. It was more expensive. That week I did my normal journey and half way through the week I thought my gauge was broken as I had only used half a tank of petrol usually would have used 3/4 tank. Filled up as usual in Tesco and thought nothing of it. Until just after Christmas I filled up at Sainsbury’s and again the petrol lasted me almost twice as long. I went to Sainsbury’s again the following week, and now will never go back to Tesco. Their petrol is obviously on poorer quality.
Can we be clear about the role of additives please? Certainly, all fuel sold in the UK (whether a premium brand or a supermarket fuel) has to meet a minimum standard, Does that standard calibrate simply the quality of the fuel alone or the combined quality of the fuel plus additives? If the latter, then surely there are two questions. 1. Is it worth paying for higher octane (petrol) or cetane (diesel) rating if the handbook does not specify this? 2. Is it worth paying for supposedly better quality additives or not? If the additives in even cheap, own-brand fuels keep the engine clean through their detergent effect, is there evidence to suggest that the extra detergent power of super fuels also removes previously-accumulated grime? Shell’s marketing suggests that it does. It would be useful to know whether any such additional detergent benefit is derived from constant use … or whether periodic fill-ups with super achieve the same effect?
I don’t agree with the biochemist’s conclusion. I know my own car runs better on branded fuel and even my sister can tell every time whether her car is running on Shell or not. Seriously and that is only by sitting in the passenger seat.
There used to be good reason not to buy supermarket fuel but now it seems even branded fuels contain alcohol based ethanol rather than pure petroleum methanol. Bio diesel is no better either. Ethanol separates and turns to water. It goes off much faster too. My experience with a bus company suggests that biodiesel jellifies readily when the temperature fluctuates greatly around zero degrees. It blocks fuel filters, causes driveability issues, brings on the MIL indicator and is probably the greatest cause of breakdowns. It also means the fuel filters must be changed far more often than the manufacturers service recommendations.
My guess is that Fubra will not support this. After all, they readily support Greenergy who brought us the rubbish biofuels in the first place. Unfortunately, I believe that there is probably no way to avoid fuels with bio content due to lower taxation. However, engines run worse, they cause internal corrosion and cause often necessitate increased servicing costs.
As a side to that, I believe the premium fuels do not contain bio matter. That is precisely a reason to use them if the engine benefits. If it doesn’t, then in the case of a petrol engine, a performance remap to take advantage of the extra knock resistance is a good idea. It is a good idea anyway as these fuels have a more sustained pressure on the piston crown which anyone with even slight a engineering grasp will realise is a good thing.
As a side to all this and I state I am in no way connected with Shell or any part of the oil of petrochemical industry, nor indeed do I have shares in such, I did notice during mg years as a mechanic that the cut price dealer serviced cars had much dirtier (gum and varnish) engine internals than specialist or reputable independent serviced cars. There was also a greater chance these cars inflicted with cut price servicing were the ones which needed major engine repairs. Again my belief on that is often attributable to poor quality fluids which do not do what the are meant to especially with regard to internal corrosion protection.
I have a motorhome and I keep a record of the mpg I get every time I fill up. Clearly there are a variety of factors that will affect mpg including the prevalent wind, the types of roads being driven and the nature of the terrain (i.e. flat or hilly). I normally use branded diesel and I average 28.9mpg; this being over 25,000 miles. A couple of years ago whilst travelling in France I thought I would try supermarket fuel to see if there was a difference. Within 2 fuel fills my economy was down to 25mpg and I reverted to branded fuel and within 2 fills my economy was back up to 29mpg. Last year I was again in France and tried using premium fuel (it is only 4c a litre more than standard fuel). After about 4 fills I found it was making no difference whatsoever and reverted back to standard fuel.
Likewise with petrol. A few years ago I had a scooter and again I only used branded fuel. One day I was getting low on fuel and the only available source was a supermarket. I filled up and set off and within a few hundred yards my wife, who was riding pillion asked what was wrong with the scooter. It was the supermarket fuel. It took 2 refills of branded petrol before my scooter was running smoothly.
The safest bet is to spread the risk and use all fuel brands, oil brands, oil filter brands. If one brand is deficient in some way it will be averaged out and unlikely to cause an issue over the life of the car.
Surely it would have been more beneficial to speak to an expert in petrochemistry rather than “a specialist in biochemistry” for this study??
I have a 2010 Toyota Rav4 diesel and I have stopped using supermarket fuels as there is definitely a difference. I have been monitoring fuel consumption very carefully over the last year, by use of the onboard computer and by doing brim to brim calculations. Firstly, taking into account the variables, using Shell or Esso, consumption is improved by up to 3 – 4 mpg – it will drop whenever I use a supermarket or one of the cheap brands; secondly, I notice a definite improvement in smoothness and engine noise when using the more expensive ultimate blends. When I filled up at the village service station, which has some mickey mouse brand I had never heard of, the car became noticeably agricultural. I belong to a SUV forum and the general consensus of opinion is that supermarket brands are definitely inferior. An additive called Millers seems the favourite and I shall be trying it when I have used up my stock of Redex. Just a bit more boring information – I know someone who will travel miles to buy the cheapest diesel and will not used additives. He has just forked out over a grand for a new set of injectors – an isolated example perhaps, but I rest my case and will continue to use Shell with one fill up every four of the V power or whatever name it goes by.
I recall being instructed not to use fuels from Morrisons or Tesco a few years ago. Is there a suggestion standards have improved since then?
There is a difference in consumption when I have used Tesco’s petrol as against Sainsbury’s Petrol with Sainsbury’s coming out slightly better! I also tried Tesco’s Higher Octane against their regular. There was a difference in consumption, but calculating it out per mile it worked out about the same