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AlanNancy

Which Fuel should I use?

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I was on a site in France a few months ago and got onto the subject of which fuel I should use. I run a diesel Volvo XC90. The chap (a Brit) said that I should not use fuel bought from Tesco or indeed any supermarket as they do not have the necessary additives that are added to the more expensive fuels - Shell V Power - etc.

Is he right? Is it worth paying the extra?

Alan   

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No, they all have the "necessary additives", though not necessarily those used in branded fuel, and not all those in premium fuels.

If you do low mileages, shorter journeys and are not inclined to "gun it", then IMO using Premium could be wise.

I use them for a month preceding the MOT, then it is whatever is the best offer where I find myself driving past. I guess this means 75% of the stuff used is a branded "regular", with no company finding particular favour.

 

 

 

Edited by JTQ

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Opinions differ! All the fuels on sale contain all the "necessary additives", but the  premium and special varieties contain more and different additives.

In theory, these contain more detergents to keep engines cleaner and I have no reason to doubt this claim.

However , from my own experience over the years, the only engine trouble I have had has been after putting one of the "extra" fuels in  engines that have done fairly high mileages on regular fuels. In one case it was increased oil consumption and in the other a stuck EGR valve.

In both instances I suspect, but have no proof, that the extra detergents dislodged carbon deposits that were doing no harm where they were. 

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Tesco's for me.  After a similar thread I tried one of the 'super fuels' Shell V I think.  Yes I could tell the difference.  Slightly smoother and more powerful.  However, even with a fractional increase in mpg it was far from worth the increased price.

 

John

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I reckon that I get better MPG from the premium Diesel.

   John.

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5 minutes ago, Leedslad said:

I reckon that I get better MPG from the premium Diesel.

   John.

 

I thought that if a Diesel injection system supplies X amount of fuel via a injector to the cylinder would it alter if it has different addictive fuels ?

 

 

 

Dave

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1 minute ago, CommanderDave said:

 

I thought that if a Diesel injection system supplies X amount of fuel via a injector to the cylinder would it alter if it has different addictive fuels ?

 

 

 

Dave

I think the logic is:  If the resulting explosion is greater then you need less acceleration therefor less fuel.  But I found the increase in mpg to be minimal.

 

John

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Working with my son with a highly stressed engine on a dyno we switched between shells optipower or whatever it was called and morrisons finest. In each case the engine was mapped to get the optimum power from the fuel in use and the difference? none.  People claim better MPG etc but a small change in driving style can do that, even a change in the weather.  There is some argument about them burning cleaner which is good for longer engine life, how many of us wear an engine out? I have done high mileages on Morrisons finest without issue many hundres of thousands of miles without any engine issues, not worth the extra money.

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IMO,  the bigger diesel issue than "wear" is "gunging up", be it the injector nozzles, the turbo hot end nozzles, the EGR and the DPF

Here  the use  of premium diesel fuel  could well be beneficial  and underlies my use of it annually pre MOTs.

 

 

 

I  suspect  they improve the burn stability  at low crank speeds,  making for a bit more refinement and possibly  improve the mpg in some engines.

I used to find that with  the old VW PD 1.9  litre diesel  Mk4 Golf, but more recent engines I fail to notice any improvement in either refinement or mpg.

 

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I have recently started using the premium diesel and think it does make a small difference.  The computer on the car is showing a small decrease in fuel consumption.  Engine is definitely quieter. 

This is from a former member who is no longer with us.

 

This topic reappears every so often, but in essence I'll quote my answer about diesel fuel - and petrol is pretty much the same story:

As the UK Representative to CEN WG9 (European standards committee for all motor vehicle fuels) all pump fuel in Europe is produced to meet the relevant EN standard - which you will see written on the pump body.
The major difference between the supermarket fuels and the branded fuels is the exact nature of the additive pack added to the fuel when it leaves the refinery - common rail pump lubricants, injector cleaners, etc.
Synthesised Diesel
The exception to this is the new "synthesised" diesel fuels, such as BP Ultimate (actually researched by Aral in Germany), Shell V-Power (may be called something else in the UK), and Total Excellium. These fuels are manufactured in the refinery by joining simple petroleum hydrocarbons into an exact diesel fuel - you'll need some experience of university level Chemistry to follow what they do - so just accept that they are better - higher cetane rating, better additive pack, etc.
Normal Diesel
This is a straight distillation fraction from crude oil, produced by the nearest refinery to the fuel depot - so for instance, diesel refined by Shell may be sold by any of the other retailers close to that Shell refinery. The major difference is the additive pack - which is brand specific - and any specification difference imposed on the refinery by the other retailers - and the addition of bio-diesel.
Bio-diesel
Another one of our EN committees, pump bio-diesel is a blend of normal refinery diesel (95%) and (5%) of pure bio-diesel. This is an EN standard and all EU countries will be (or are) selling this bio-diesel as a direct replacement for normal diesel. All the car manufacturers have accepted this 95:5 blended fuel, and we are working on specifications for a 90:10 blend.
Pure bio-diesel is manufactured by mixing and heating vegetable oil with methanol (methyl alcohol) and sodium hydroxide (caustic soda). This splits the vegetable oil into glycerine and fatty acids, which immediately reacts with the methanol to form a "fatty acid methyl ester" or FAME (bio-diesel).
FAME is perfectly fine as a diesel fuel, it has very good lubricating effects - and replaces the lubricant additive in a normal diesel fuel - except that it is not as stable as normal diesel - it tends to go "sour" or "rancid", which is why the car manufacturers don't like you to run a car on pure bio-diesel. Not a problem as a 95:5 blend.
Vegetable Oil
Reasonably OK for an old (pre 1995) diesel engined car - except that the car won't start on cold vegetable oil, but once the engine is running it's OK.
Other problems are that vegetable oil quickly turns in a gummy glop (like the linseed oil that artists use) and the car's fuel system and that the engine needs a lot more maintenance - blocked injectors, gummy residue in pumps and cylinders, etc.
After market additives
After market products like Millers improve the cetane rating of standard diesel, but only when the engine is cold - interestingly it doesn't help a hot engine - so cold starting is usually quieter but no difference to a hot engine - and Millers does provide good, additional pump lubricity.

Self Tuning Engine Computer
So, if your diesel engined car "self tunes" then try Shell V-Power, BP Ultimate, Total Excellium - I see between 3% and 5% improvement in fuel consumption. My Mercedes C270 returned 52.8 mpg driving from Rotterdam to Wendover yesterday - on Dutch Shell V-Power - 320 miles at speeds of around 60, 70 and 80 mph depending on the country / road speed limit - using the electronic speed limiter.  If not, stick with the regular diesel fuel, and add Redex or Millers at the recommended dosage level - adding more won't improve the performance. And don't be dismissive of supermarket fuel, it can and often is identical to branded fuel.
And if you add Redex or Millers or switch to a branded fuel, then any change to the cleanliness of the injectors won't show itself for quite a few hundred miles, but pump lubrication and maybe a higher cetane rating will show an effect much sooner - depends how much old fuel was in the tank and fuel lines - and how much the old fuel dilutes the action of the new fuel.
So is there a difference between supermarket and branded fuel ? - there can be - but often there isn't.
How can you tell if one fuel is better than another?
To compare the fuel consumption, you need to exactly reproduce two journeys - exactly the same speed, exactly the same acceleration and braking, and under identical conditions:
Atmospheric Pressure
A one percent change in air pressure has an identical effect on power and torque - so driving on days with high pressure makes the engine generate more power
Temperature
Driving on hotter days reduces engine power.
Humidity and Rain
Driving on days when it is humid or raining significantly improves engine power - water injection is used in truck racing and sucking in damp air has a similar effect in increasing power.
These produce percentage level effects on mpg - making it difficult for the driver to make comparisons. Driving on a cold, damp day may see an improvement of 3% or more compared to a hot, dry day.
Even more important are the effects of different traffic levels and the inability of drivers to EXACTLY reproduce a journey on UK roads, for instance:
Speed
A 1 mph increase in speed (say 60 instead of 59) will make about a 2% difference in fuel consumption - rolling friction and wind resistance increase exponentially - on top of the extra fuel need to spin the engine that bit faster.
Unless you drive everywhere using an electronic speed limiter or digital cruise control then it's impossible for most drivers to reproduce even a constant speed.
Acceleration and Braking
Big percentage differences here - and unless you are driving on an empty test track - the effects of other traffic, let alone how you drive the car, have effects at least as large as the difference attributed to different fuels.
Summary
There is a reproducible improvement of between 3% and 5% by buying the synthesised diesel fuels - BP Ultimate, Shell V-Power, Total Excellium, etc - compared to the standard branded diesel fuels.
There are smaller differences between supermarket and standard branded fuels - sometimes they are physically the same fuel - sometimes they differ only by the additive (cleaner) pack - and sometimes they are different.
Day to day variations in the weather, driver reproducibility and traffic make it very difficult for drivers to reproduce journeys.
Comparing two fuels
If you do want to make a comparison, drive your car until the fuel tank is almost empty, then fill the tank and after you have driven 200 miles (any old fuel should have been used up), drive at a fixed speed on a motorway for 10 miles and record the fuel consumption.
Then the next time you fill up, repeat the exercise with a different brand of fuel - but remember to test on exactly the same section of motorway and on a similar day.
Checking your fuel consumption over normal driving, in stop start traffic, over a period of weeks - just tells you that you have had to driven differently.
And don't forget the placebo effect. Robert

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At home, I use Asda diesel almost all the time, because it's cheapest, but with regulart doses of Millers - occasionally I use Morrisons which I perceive runs slightly smoother - on our present holiday, one fill was Tesco which was definitely smoother and two fills were Esso which was no different to Asda.

 

Despite using brim-to-brim rather than the trip computer, I can't get any repeatability of MPG as the usage pattern within each fill can vary so much - without that repeatability any claims of MPG improvement are suspect.

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I would be very surprised if any of the major supermarkets or other budget suppliers did anything other than buy, by the tankerload, or hundreds of tankerloads, the cheapest fuel available, subject to conforming to the appropriate EN standard.

On any given day, different branches of the same supermarket may be selling fuel from different refineries and supermarkets of different brands may be selling fuel from the same refinery.

Likewise there is no certainty that one supermarket filling station will be selling fuel from the same refinery from one month to the next.

 

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29 minutes ago, Stevan said:

I would be very surprised if any of the major supermarkets or other budget suppliers did anything other than buy, by the tankerload, or hundreds of tankerloads, the cheapest fuel available, subject to conforming to the appropriate EN standard.

On any given day, different branches of the same supermarket may be selling fuel from different refineries and supermarkets of different brands may be selling fuel from the same refinery.

Likewise there is no certainty that one supermarket filling station will be selling fuel from the same refinery from one month to the next.

 

 

The same applies to the big brands - in any one locality, all regular fuel come from the same storage tanks at the local distribution depot with brand-specific additives added at point of delivery to the filling station.

 

The EN standards specify a minimum additive specification - how much any brand exceeds that isn't known as chemical formulae are never published.

 

Believe marketing hype at your own risk.

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It was BBC watchdog or Rip of Britain the other day said the gung in the fuel station was a thing to worry about.

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On 18/10/2019 at 17:25, AJGalaxy2012 said:

without issue many hundreds of thousands of miles without any engine issues, not worth the extra money.

+1. I sold my last taxi (VW Passat 1.9 TDi 2005) when I retired. It had 306,000 miles o the clock without ever having the "benefit" of premium fuels. Normally, I would fill up at Sainsbury's or Tesco, with an occasional stop at Asda. I saw the car a year later; still in use as a taxi with, probably, another 50,000 miles on it. 

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2 minutes ago, David 38 said:

It was BBC watchdog or Rip of Britain the other day said the gung in the fuel station was a thing to worry about.

 

That's why high turnover supermarket filling stations  have much to recommend them.

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Gunge is certainly a problem nowadays. The Govt. decreed that bio fuel be added to raw diesel.

I think that it's around 7% at present. Reactions take place and this is what produces gunge.

Depending on your regular fuel source, it may be prudent to change the fuel filters more frequently.

With super diesel, you must do your sums to ascertain if it's worth the extra cost or just add a can of fuel line cleaner now and then.

What I found with super diesel was that it gave me a little more power when towing the big tin shed, especially on hills, as I run somewhat under powered.

Edited by blondchaser

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Years ago I convinced myself I was obtained better fuel consumption and power using Shell or BP in my Audi A4 and Honda CRV's, then I brought a Ford Kuga Diesel on lease, now I only use so called cheap supermarket fuel and too be honest all those years I have been kidding myself it does not make the slightest difference.

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15 hours ago, Black Grouse said:

At home, I use Asda diesel almost all the time, because it's cheapest, but with regulart doses of Millers - occasionally I use Morrisons which I perceive runs slightly smoother - on our present holiday, one fill was Tesco which was definitely smoother and two fills were Esso which was no different to Asda.

 

Despite using brim-to-brim rather than the trip computer, I can't get any repeatability of MPG as the usage pattern within each fill can vary so much - without that repeatability any claims of MPG improvement are suspect.

Taking into account the cost of Millers surely it is just as cheap to use a branded fuel.  If supermarket fuel is so good why use Millers?

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The Rip Off Britain wasn't just diesel, it was water in petrol as well.... 

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15 hours ago, Black Grouse said:

 

 ......  The same applies to the big brands - in any one locality, all regular fuel come from the same storage tanks at the local distribution depot with brand-specific additives added at point of delivery to the filling station....

 

 

 

I think you'll find that the only example of 'doping' at the point of delivery at the filling station is Costco.

 

Other than that the distribution system up to and including the last point of bulk storage does indeed contain 'un-doped' fuel. The doping takes place as the fuel is loaded on to the tanker vehicle at the distribution depot. The equipment used to dope fuel allows for extremely precise control of the additives (as you would hope and expect) and records the activity providing trace-ability for ever vehicle compartment that is loaded.

 

 

 

Edited by jetA1

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21 hours ago, Black Grouse said:

At home, I use Asda diesel almost all the time, because it's cheapest, but with regulart doses of Millers - occasionally I use Morrisons which I perceive runs slightly smoother - on our present holiday, one fill was Tesco which was definitely smoother and two fills were Esso which was no different to Asda.

 

Despite using brim-to-brim rather than the trip computer, I can't get any repeatability of MPG as the usage pattern within each fill can vary so much - without that repeatability any claims of MPG improvement are suspect.

 

I've always found Tesco to be the best and Asda the worst, but Asda is usually the cheapest where i live, the other two i use when they are fuel discount offers or when convenient.

 

 

19 hours ago, Oscarmax said:

Years ago I convinced myself I was obtained better fuel consumption and power using Shell or BP in my Audi A4 and Honda CRV's, then I brought a Ford Kuga Diesel on lease, now I only use so called cheap supermarket fuel and too be honest all those years I have been kidding myself it does not make the slightest difference.

 

You will get more MPG with the expensive fuels such a V-power, but the cost offsets any savings.

 

 

6 hours ago, Durbanite said:

Taking into account the cost of Millers surely it is just as cheap to use a branded fuel.  If supermarket fuel is so good why use Millers?

 

Never used Millers, it no advisable to use it IMO as the handbook usually says fuel additives can harm the emission system fitted. 

 

 

Edited by xtrailman

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8 hours ago, Durbanite said:

Taking into account the cost of Millers surely it is just as cheap to use a branded fuel.  If supermarket fuel is so good why use Millers?

 

100 ml of Millers every 1,000 miles costs a fraction of the price differentioal for premium fuel

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I may have missed this in one of the replies but my understanding of the v-power type fuels is that they contain more "energy" per litre and that for performance cars, this is indeed noticeable.

 

I didn't think it was about mpg although if there's more energy per litre then that's going to result in an increase of mpg or more importantly the performance of your super-car...

 

 

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6 minutes ago, PandR said:

I may have missed this in one of the replies but my understanding of the v-power type fuels is that they contain more "energy" per litre and that for performance cars, this is indeed noticeable.

 

I didn't think it was about mpg although if there's more energy per litre then that's going to result in an increase of mpg or more importantly the performance of your super-car...

 

 

Energy per litre and fuel consumption are inextricably linked.

At full throttle, the more chemical energy and oxygen that can be crammed into a cylinder the more power comes out. Under constant power conditions (cruising at constant speed!) the more energy per litre the less fuel is needed. 

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