Premium diesel - more MPG?

[motacyclist]

A couple of posters have said on another thread that using premium diesel makes a significant improvement in MPG.

Has anyone else tried it?

It sounds like it's worth trying a tankful or too, so if anyone wants to give it a go, let us know how you get on and we'll see if the extra cost over normal diesel is worthwhile.

 

[snowy55]

I tried a couple of tank fulls but couldn't see any difference in MPG or smoothness, but others swear by it.

 

[WelshGas]

Personally I think it is wishful thinking.

 

[johnyboy]

I used to do 30k miles a year in a Discovery 3 - this gave me the opportunity to get geeky on Diesel MPGs

Worst - Supermarket
Middle of the road - branded BP, Shell, Esso
Best MPG (usually by at least 10%!): Shell V Power, BP Ultimate.

At the time the cost difference between premium and regular was such that it made more sense to run on it all the time. I was genuinely suprised that there was a difference a) between supermarket and branded fuels and b) the premium

 

[jeff]

She'll v-power 36mpg constant. Normal unbranded diesel 32mpg never used supermarket diesel .

 

[MadMechanic]

I work in tech for Audi and this is discussed a lot on other forums.

The main thing to remember is you MUST use premium fuel from brand new , if the vehicle is pre owned or was previously filled with supermarket fuel you are wasting your money by switching to premium.

Also, don't take any notice of the OBC, you need to work out your calculations manually.

 

[motacyclist]

I work in tech for Audi and this is discussed a lot on other forums.

The main thing to remember is you MUST use premium fuel from brand new , if the vehicle is pre owned or was previously filled with supermarket fuel you are wasting your money by switching to premium.

Also, don't take any notice of the OBC, you need to work out your calculations manually.

Too late for me then

 

[Maud]

The main thing to remember is you MUST use premium fuel from brand new , if the vehicle is pre owned or was previously filled with supermarket fuel you are wasting your money by switching to premium.

Hi MadMechanic,
Could you explain why this is the case please? I am not very technically minded!
Thanks,
Maud

 

[F5 JNR]

All about the cetane conten, boosters and cleaning agents. Supermarkets allegedly buy bulk deals of chips, milk, eggs etc from wherever they get the best bulk buying power, their fuel deals run the same. one day you can fill diesel from tesco and its from a tanker of bp ultimate, next it might be lower grade for commercial vehicles and hgv. Its roulette thats why is a few pence cheaper. From research think its safe to write that your engine drinks a less varied diet if using premium branded fuel, which is better for the ecu which can focus on optimum fuel efficiency rather than spending confused time adjusting to different fuel every time you refuel.

 

[SimplyDubs]

Similar to a couple of comments above...

I run the T4 Multivan on either supermarket or VPower.... Supermarket (Tesco I get 38 to the gallon consistently, VPower I get 42)

It feels smoother, and quieter but without measurement this may well be a perception thing.

All other vehicles I run Tesco... the 16 or so pence per litre we currently get off with points makes it more than worthwhile.

Never had an issue with filters, DPF etc on any of the diesels we run.

Have run Diesel Rhino in the T4 for a while... made a significant difference after a couple of weeks, but personally didn't ultimately think it worth the hassle.

 

[zennorboy]

I use SHELL V-Power all the time and like to think the engine runs smoother, quieter and provides more miles per litre.

My best run to date is from The Lake District to Southampton, two adults and fully loaded with awning and other assorted camping stuff on an engine with 140,000+ miles on the clock, achieving 44mpg overall worked out with arithmetic and (more or less) supported by the on-board computer...it was all downhill of course!

My local VW Van Specialist recommends it and on occasions when I have used supermarket stuff I don't think it runs so sweet and I'm reasonably sure I don't get the same mpg.

Annoyingly, SHELL don't provide diesel V-Power at all of their outlets.

 

[aileron346]

Yes...I think it does make a difference. Feels smoother, quieter to me and I reckon does improve mpg between 10-15% especially on long motorway drives. Just rough guess because in real life how can you ensure the driving style, road terrain, queuing etc etc are all comparable. I don't worry if I can't get the premium every time, but definitely reckon it makes a difference. Certainly there are different opinions out there though.

 

[Bearonwheels]

The Consumers Association, which is funded by its members (and not the oil giants or motor manufacturers or indeed anyone else) found there was no discernible difference between these premium fuels and standard ones in relation to mpg or performance. Other factor such as properly inflated tyres, driving style (how heavy footed you are) and the type of journey are all much more significant. So Asda's finest it is for me.

Thats not to say you can't buy poor quality diesel. If the underground tank is getting towards empty you will be buying the dregs at the bottom of the tank - so more water (this can come from condensation, tank leaks and even the fuel itself which contains some water too) than the stuff at the top when the tank is full and even some sediment. There is no way to avoid this.

From a psychological perspective there is a high degree of 'confirmatory bias' with these fuels - that is if you think something works, it will. Another name for this is the 'placebo effect' - which is why drug companies are required to undertake double blind randomised trials of new drugs - neither the proscribing physician nor the patient know if they are getting the real drug or a dummy (placebo). That way when the results are reported and the decision made as to whether the drug is an improvement on current treatments you can see whether or not it does. So next time have you better half fill up the Cali and make sure they don't tell you what its filled with….

 

[zennorboy]

With reference to F5 JNR's post above, is there at least some benefit in mpg and engine efficiency by using a fuel such as SHELL V-POWER, which one would assume has a consistent formula and chemical construction, over supermarket fuels which may vary in origin and quality?

I guess if you are not going to keep a vehicle for many years and many miles it might not matter that much.

I have seen any number of different delivery tankers in our local supermarkets and some years ago (with another vehicle) fell foul of what my local dealer said was the 'low tank' situation (at a local supermarket) when the whole fuel system had to be cleaned as it was full of what looked like a coppery sludge.

 

[Bearonwheels]

I think you are mistaking fuel source for fuel delivery.There are only a limited number of oil refineries in the UK - six I believe and not all of these produce diesel. Much is imported from mainland Europe. These refineries are owned by the usual suspects - the oil majors and companies like INEOS.

What you are seeing at supermarkets are different delivery companies - its a haulage contract, albeit a specialised one. There are myriad delivery companies but the fuel remains the same - it is produced to comply with the British / European standard for diesel - BS EN 590: 1997. The standard is exacting, setting out requirements for maximum water percentage (0.02%), cetane, sulphur and a whole host of other chemical substances. Since 2007 it is labelled 'Ultra Low Sulphur Diesel' at the pump (I hadn't realised that the bio-diesel component makes modern diesel fuel hygroscopic - so it will deteriorate over time - unlike diesel of old).

My understanding is that the premium fuels have various additives but they must still comply with the standard. Or else what are motor manufacturers to work with? Our vehicle only runs on BigOil super Seven fuel - which costs 25% more? There'd be trouble….

The low tank issue is just as as much of an issue with premium fuels as with standard ones - it just happens less often as no one is prepared to be pay!

 

[campandfly]

Wanting to keep my new Cali in top form, I try to look if there is any info at the pump as to what you are buying, there is not much available so far other that the BS En number.

Found this online for Shell VPower Diesel
http://www.shell.co.uk/motorist/she...tro-plus/shell-v-power-nitro-plus-diesel.html

After using the locator I think I will try a few tanks and see how it goes
http://www.shell.co.uk/motorist/station-locator.html

 

[briwy]

The advantage of using premium fuel is the life of the engine. Performance and mpg may not alter significantly (certainly not enough to justify the extra cost) but as already mentioned the addatives will prolong the engines lifetime and reliability.
We were camped at a Moto GP event in Spain last year next to a guy on a big BMW touring bike who turned out to be an ex CEO of Shell UK. Very interesting chat about premium fuels and he says Shell do back to back engine testing with other fuels and the long term results prove the benefits of a premium fuel. (Not just Shell incidently)

 

[GrannyJen]

On the grounds that I will probably be on my third cali before the engine on my first is knackered I think I will continue to plonk in standard fuel and spend the difference on s nice glass of wine

 

[Rob H]

To date having run diesel vehicles for last twenty years, biggest improvement in mpg I can identify, and this relates, especially on older diesels, to the simple induction system, comes from changing air filter more frequently than manufacturers recommendations, newer diesel engines with airflow sensors and sophisticated ECU's vary fuel injected to the air 'mass' they can initially 'suck' in through a blocked filter ? subject to your right foot, lower driver perceived power output leads to a subconscious heavier acceleration demand, I've found buying and self fitting quality aftermarket air filter from GSF and Europarts factors at lower price than main agents (air filters for what is a commercial vehicle are designed to be quick and easy to change), fuel saving more than covers the cost. With newer diesels, (Euro 5 engines), suspect fuel consumption varies as engine approaches its DPF automatic regeneration cycle but not easily possible to identify when this is going to occur, maybe 'add blue' systems migrating now from HGV's to newer small diesel engines have different MPG efficiency characteristics, ( and maybe even a reliability edge over sticking EGR's ) who knows where public opinion v new R&D will take us diesel heads ... lol ..

Rob H.

 

[Bearonwheels]

Well I for one tend to treat anything said, written, published or claimed by oil companies with a 25kg bag of salt. That thinking applies to research they pay for too, be it from universities, research companies or anyone else. He who pays the piper calls the tune (and writes the claims too). And I say again, the Consumers Association found no replicable evidence of ANY of the claims made by the oil companies re these fuels. And so for believing what CEOs say… do you believe what the CEOs of banks say?

As for the air filters, I can see the logic - but its beyond my knowledge. But correctly inflated tyres, regular oil changes and journey awareness (the AA and the RAC and some car dealers will out you off buying a diesel if you only do short journeys - you will destroy the DPF) all play a part.

Treat the oil company claims carefully - but there again it is a free country - spend you money how you will!

I'm with Granny Jen on this one…. spend the money on wine, for as Keynes said, 'in the long run, we are all dead anyway!'

 

[campandfly]

Trying to look after my Cali engine, will try and avoid short unnecessary journeys and like to give it a good run now and then.
My question is what constitutes a short journey?
eg. just distance related, irrespective of hills, speed or the engine oil reaching a specific temperature.
perhaps someone more knowledgeable on the subject can advise a newbie diesel driver.

 

[GrannyJen]

When my VW arrives on the scene with the manufacturer, who at a minimum guarantee's the working life for 3 years, tells me that to fill with chateau de crap diesel sans additive invalidates the warranty then I will believe in paying a premium price. Until then the lack of such advice from the manufacturer guaranteeing the engine speaks volumes.

My Cali will have done 60,000 miles when I trade it in. No one will ask me what I have run it on, I'm asked for no details of fulfilling the "right" diesel requirements, why should I pay 10ppl more just for the feel good factor?

 

[briwy]

Just to be clear. I too take what companies claim with a pinch of salt but what the Shell guy was talking about is the use of standard branded (not the super premium) fuels as opposed to the cheaper supermarket stuff. He agreed that the use of the super fuels is not really relevent in a diesel, more so for higher powered petrol vehicles.
Personally I'm not in a position to be changing our Cali every few years so am looking at it long term and having had bad experiences with supermarket fuels in the past I'm sticking with branded products. Locally there is no price difference anyway.
Re air cleaners. I agree completely. One of the first things I do on a vehicle is fit a K & N filter. better performance and cheaper long term.

 

[briwy]

Trying to look after my Cali engine, will try and avoid short unnecessary journeys and like to give it a good run now and then.
My question is what constitutes a short journey?
eg. just distance related, irrespective of hills, speed or the engine oil reaching a specific temperature.
perhaps someone more knowledgeable on the subject can advise a newbie diesel driver.

Well it's said that it takes an engine around twenty miles before it's fully warmed up, this is the actual engine rather than the the coolant temperature. On a Cali you can see the oil temperature in the display and this is probably a better indicator of engine temperature than the coolant temperature guage.
Diesels, being more eficient than petrol engines do take longer to warm up though.
As already mentioned regular oil changes will also help look after the engine.

 

[AndyFromTheBrac]

We all are creatures of habits and those habits do vary from person to person.

Most of us don't have the resource to conduct proper scientific research into whatever works best for us, but rather we have an opinion of what it is we like/want, then use that to try and fit whatever it is we need to do. Its mostly anecdotal.

How often, hand-on-heart, have you seen a car that you like the look of, then use the various reports and reviews to justify that choice. E.g. you know a Skoda or Seat is engineered in the same manner, uses almost identical components, is cheaper than a VW and makes perfect sense, but you go for the VW anyway "oh higher residuals". We can't all test drive every vehicle and make an objective choice. It makes us happy.

Same with fuel use - many branded outlets are franchised and run using slightly different standards to the next same-branded station down the road. Some supermarkets are better than others at keeping their sh*t clean. A little like the experience we have with different dealers.

It's all a personal choice and I think that if it helps to keep your blood pressure down and providing you're not doing something totally bonkers, then you just keep on doing what you're doing

PS I wouldn't worry about short trips unless that's almost all you're doing. Arguably it's better than letting it sit idle; it's a van when all is said and done. Just my opinion