Premium Diesel Long Term Test

[RobGy]

I am planning to do a long term test on the effects of using various premium and regular diesel fuels in my 2014 Octavia MkIII 1.6 TDI 110 Elegance Estate.

This will be a very nerdy thread which I intend to update as time goes by with results and observations.

 

I have only owned the car a few weeks and just done my first brim to brim test, albeit at a different fuel station which can make a difference due to the sensitivity of the pump shutoff.  I used 44.49 litres over 490 miles giving 50.7mpg.  OBC read 53.  That was on Costco diesel at 124p a litre.  Brim to brim done by filling to first click, waiting 10 secs, filling slowly til second click.

 

I have just filled it with BP Ultimate at 139p a litre.

 

My commute, which comprises about 45% of my annual mileage, is a 34 mile round trip of mostly A roads and a bit of dual carriageway.  I cruise at 40 on the A roads and 60 on the dual carriageway for the most part and get around 60-65mpg depending on various environmental factors.  I do a fair bit of urban driving for work hence my average being lower.  That has also been due to getting a new car and giving it a thrash a few times to see what it'll do.

 

I will at some point be taking it on some long motorway cruises but it just so happens none have cropped up yet.

 

I plan on running it on BP Ultimate for probably 2-3 tankfuls and then reassess what to do next. 

 

I'll update here with quantitive and qualitative assessments of how it's going.

 

Anyone got any thoughts or experiences to share?

[shyVRS245]

Although I run a petrol Vrs I am currently doing the opposite experiment to yours. Having used 99 octane Shell V-Power since new in August 2017 and over 25,000 miles at £1.429 per litre with an overall average of 40.55mpg. Over the last 3 tanks I have used 95 octane BP standard unleaded at £1.279 per litre over 1,183 miles using 125.87 litres (27.69 gallons) for an average of 42.72mpg. Incidentally the OBC is showing 41.7mpg and has always under read.

[Gerrycan]

I wish you luck but there are a lot other factors that need to be taken into consideration.

Traffic variations on standard commute eg long term road works, school holidays. Effective average speeds. Temperature variations summer/winter/diurnal and aircon use. Seasonal fuel formulation variation. Amounts dispensed from different pumps. Precipitation, road surface consistency, tyres summer/winter/size/brand/etc.

Weight of goods and passengers in vehicle.

I am sure there are lots more but that is are a few to think about.

 

This is why experiments are mainly run on rolling roads in enclosed labs with known and measure fuels and people still complain about their accuracy.

 

I will still be interested in following the thread though. 

Edited 7 October, 2019 by Gerrycan

[threadbear]

I run a 1.6tdi 110 SE Hatch and have a 28 mile round trip commute which is mostly motorway and regularly get 60 mpg without really trying. I haven’t been to a supermarket in years for fuel and predominantly use BP diesel, mainly because they have the most sites in my part of Kent. I’ve never been very scientific with my fuel calculations but if I get 490-520 miles out of a tank, I’m happy. 

 

My Octavia is the most economical car I’ve ever owned. 

Edited 7 October, 2019 by threadbear

[wyx087]

Interesting thread, do keep us posted.

 

But as said, it will be difficult to remove all variables. In tests like these, be careful of your placebo effect, it's better to do a double blind test. Eg. get someone else to fuel up for you.

 

 

 

My Octavia is also the most economical fossil fuel car I've ever owned......... until I started commuting with an EV. Now my Octavia only get used when we need a second car, because fossil fuels are expensive.

[TDIum]

What difference are you expecting to see?

I don't believe you will be able to observe any difference in consumption/economy. You won't be able to measure the amount of sulphur in your soot. 

[ScoutCJB]

I've had my Scout nearly 2 years, i have only ever put Shell in since purchasing and thats about 75k  --- no idea what it was run on prior to me buying it obviously.

Whether std diesel and Vpower and didnt see any difference in standard mpg - it goes up and down dependant on regens etc but my normally journey that takes about the same amount of time, at same speed etc ... no difference

 

What i would say is on my old scout i ran various fuels but the worst was a supermarket brand diesel and the car ran badly for the duration of a number of tanks.  A few tanks of shell and the issue went away ..Not scientific, just real life experience

[TDIum]

Even the crudest supermarket slop will meet the relevant standards that all Euro cars are specified to run on. 

[RobGy]

5 hours ago, Gerrycan said:

I wish you luck but there are a lot other factors that need to be taken into consideration.

 

 

You're absolutely right, hence my warning about a nerdy thread and the need for qualitative assessment as well as quantitive.  I'm not expecting to get a scientific, conclusive proof one way or another.  But I am intrigued as to whether there is any human-appreciable difference once I have done this over a long period and tried as best I can to account for the many variables. 

 

This won't be a "I got x mpg on super vs x mpg on reg" thread, it will be a boring old fart from Yorkshire grumbling about spending extra pennies and discussing traffic volumes, luggage load and weather conditions.  EXCITING HUH?!

[RobGy]

1 hour ago, ScoutCJB said:

..Not scientific, just real life experience

 

That's what this is intended to be a long term real life experience, but this thread will become a semi-structured record (largely for my own purposes, but if there is someone nerdy enough to find it useful then great) of my completely non scientific observations.  I will report on both OBC and brim to brim.

 

Someone asked what am I expecting to see.... not much other than my wallet get thinner faster!  But let's see.  Some claim the engine runs smoother, less DPF regens, better consumption.  Others say it's snake oil.  I have very few preconceptions.

[KenONeill]

5 hours ago, Gerrycan said:

This is why experiments are mainly run on rolling roads in enclosed labs with known and measure fuels and people still complain about their accuracy.

You're confusing repeatability with relevance to the real world.

[Ootohere]

@RobGy

Are you aware that around the 15th October Winter Grade Diesel will be starting to getting delivered to filling station tanks in Scotland and the North of England.

?

When will it be delivered in Standard Diesel or Premium Diesel to where you buy your fuel?

[Guest]

A nerdy thread? I don't think so, it'd be great to find out if one fuel is better than the other.

 

A pointless thread? Well probably. The problem you have and that of every other test is no two journeys are the same, especially this time of year when daily temperatures differ enormously. Looking outside right now I see strong winds - so are all your journeys going to be in to a headwind or tailwind? Will it be when the temp is 3C in the morning or 16C in the afternoon?   What I'm saying is you can never create an equal playing field.  The only way to conduct a reasonable test is to conduct it say over a year using one fuel and then over a full year using another.

 

The tests I'd like to see is:

 

1: take two brand new cars and drive them both over same route back to back. No motoring hack seems to have done this.

 

2: The other test I'd really love to see is for those who swear one fuel is better than the other - you get more mpg, better performance etc.  Take a dozen folk, the magazine pays to fill their cars say for one month using one fuel and the other using 2nd fuel.  Of course you could play dirty and only use the one fuel-type for both months but tell them one month was ordinary fuel, one month was premium and then ask them which fuel is which. I'd really love to see the answers from those 'experts' who think they can tell the difference.

 

I'd bet there's no difference, that it's all mind games. Perhaps scientifically there's a difference but it'll be too small for Mr Average Motorist to tell.

Edited 7 October, 2019 by Guest

[RobGy]

1 hour ago, Scot5 said:

A nerdy thread? I don't think so, it'd be great to find out if one fuel is better than the other.

 

A pointless thread? Well probably. .....

 

I'd bet there's no difference, that it's all mind games. Perhaps scientifically there's a difference but it'll be too small for Mr Average Motorist to tell.

 

That's kind of what I'm expecting, very little noticeable (or, more importantly, attributable) difference.  All the variables you and others have mentioned, environmental conditions, difference in pumps, temp when filling up, traffic, road conditions, blah blah blah. 

 

This will be very unscientific, I don't doubt that.  Let's see how long I can be bothered to keep it up for.  The longer the better, to reduce margins of error, not that I will ever reduce them to a point of it being a reliable test.  But let's see!

 

Ultimately this "test" will cost me about £5-7 extra per tank, which is every couple of weeks, assuming there is no increase in mpg.  We will see how long it takes before the Yorkshireman in me demands that I stop and buy the cheapest diesel I can find, or whether I end up convinced it's worth the extra.

1 hour ago, Roottootemoot said:

@RobGy

Are you aware that around the 15th October Winter Grade Diesel will be starting to getting delivered to filling station tanks in Scotland and the North of England.

?

When will it be delivered in Standard Diesel or Premium Diesel to where you buy your fuel?

 I'm in the north of England.  It will be here soon.

[MarkyG82]

I've just crunched some numbers based on the following assumptions which should cover a number of members on here:

 

Standard diesel = 132ppl

Premium diesel = 145ppl

Annual mileage = 15k

Base mpg = 50

mpg increase due to premium = 5% (52.5)

 

Annual cost of fuel using standard is £1800

Annual cost of fuel using premium is £1977 (assuming same mpg)

Annual cost of fuel using standard is £1883 (assuming gain in mpg)

 

So, premium fuel costs just under £200 extra a year based on a relatively high mile user and no increase in economy.

Based on an increase of 5% yo pay only £83 more.  I've also just put 10% in and it comes out £2.48 cheaper over a year using premium fuel but an increase of 5 mpg is not likely ime.  More likely 2-3% if anything.

[Ootohere]

Standard diesel right now at ASDA / Tesco etc 125.7 - 127.9 pence.  Much cheapness.

Branded 130.9 pence a litre plus and add 10 pence plus a litre from Premium.

 

 

@RobGy

Good, 

get your scores on the doors now then, and you might notice a difference with tanks of the Winter Formulation.

 

I find an instant improved economy in my 2.0 TDI SCR as the good stuff (winter diesel / cheapest price) arrives at the filling station i use as it is just usually much the same weather 2nd week October & the week after, and i do the same trips time after time and know the ranges i get.

Other will say Winter Diesel gives worse economy, and maybe on short trips with more de-icing, defrosting, longer to get oil up to temp etc they do.

I drive 27 miles before filling up though and am then doing another 130 miles plus before stopping and the same average speed camera roads.

Same again before refilling.

 

October 2017 and the first winter fuel was going in the tanks.

Greenergy is supplying a lot of the Diesel in the UK, to Tesco, Esso and others.

Edited 7 October, 2019 by Roottootemoot

[TDIum]

31 minutes ago, MarkyG82 said:

mpg increase due to premium = 5% (52.5)

 

 

Citation needed 👨‍💻

Engine doesn't know the difference between one fuel and the next. Engine cycle the same. Energy content of fuel the same. Consumption the same. 

[ChoonDoode]

I appreciate the benefits to running premium diesel over standard aren't going to be necessarily as noticeable as the 95 ron and 99 ron equivalent tests................HOWEVER................ for as long as I can afford to put the, so called, 'premium' diesel in, then I will.

 

I've said on other threads about my uncle and his taxi coming up to testing time and how giving it an Italian tune up with 'regular' doesn't cut the mustard, but as soon as you throw a tank of the 'premium' in, the car runs better, sounds better and hasn't an issue going through the test.

 

So based on those real world tests which I've seen first hand, I'm of the opinion the snake oil in the 'premium' must be doing the engine some benefit.

Edited 7 October, 2019 by tunedude

[MarkyG82]

4 minutes ago, TDIum said:

 

Citation needed 👨‍💻

Engine doesn't know the difference between one fuel and the next. Engine cycle the same. Energy content of fuel the same. Consumption the same. 

 

No citation needed.  It was an assumption* and I showed the result of no increased mpg as well as increased mpg.

 

* finger in the air guess.

[MarkyG82]

43 minutes ago, Roottootemoot said:

Standard diesel right now at ASDA / Tesco etc 125.7 - 127.9 pence.  Much cheapness.

Branded 130.9 pence a litre plus and add 10 pence plus a litre from Premium.

 

46 minutes ago, MarkyG82 said:

I've just crunched some numbers based on the following assumptions which should cover a number of members on here:

 

Standard diesel = 125.7ppl

Premium diesel = 135.7ppl

Annual mileage = 15k

Base mpg = 50

mpg increase due to premium = 5% (52.5)

 

Annual cost of fuel using standard is £1714

Annual cost of fuel using premium is £1850 (assuming same mpg)

Annual cost of fuel using standard is £1762 (assuming gain in mpg)

 

So, premium fuel costs just under £136 extra a year based on a relatively high mile user and no increase in economy.

Based on an increase of 5% yo pay only £48 more.  I've also just put 10% in and it comes out £31.86 cheaper over a year using premium fuel but an increase of 5 mpg is not likely ime.  More likely 2-3% if anything.

 

I've quoted my post with the change in fuel prices you have.

Edited 7 October, 2019 by MarkyG82

[Ootohere]

When the diesel has no difference in the cetane then it can only be the detergent package really making the difference.

As to taxi's not getting through UK Mots, that will likely be the difference of a tested while the car / engine hot or not, or right after an Italian Tune Up.

Hard to have a Diesel Taxi fail on emissions in the UK, and if they only get 'Special Fuel' come test time all the more reason to do roadside tests and catch out the smokers...

 

Tests done at stations where the car is not even present or the probes are not in the right tail pipes are still a UK Scandal.

 

 

I had a wee smile at the fact the cop cars engine was ticking over all the time, no worries about emissions for them.

 

Edited 7 October, 2019 by Roottootemoot

[J.R.]

15 minutes ago, TDIum said:

 

Citation needed 👨‍💻

Engine doesn't know the difference between one fuel and the next. Engine cycle the same. Energy content of fuel the same. Consumption the same. 

It certainly does, all engines from 1995 have been equipped with a knock sensor which will run the maximum ignition advance = maximum economy without detonation causing engine damage, its why high performance vehicles can run either 95 or 98 Octane and will perform better on 98.

[KenONeill]

4 minutes ago, J.R. said:

It certainly does, all engines from 1995 have been equipped with a knock sensor which will run the maximum ignition advance = maximum economy without detonation causing engine damage, its why high performance vehicles can run either 95 or 98 Octane and will perform better on 98.

Which is irrelevant to a diesel, as per the OP.

[Ootohere]

Relevant to the post that the reply was to. As to diesels not.

[TDIum]

46 minutes ago, MarkyG82 said:

 

No citation needed.  It was an assumption* and I showed the result of no increased mpg as well as increased mpg.

 

* finger in the air guess.

 

Ok, but to the casual reader, it may seem that the 5% increase is a reasonable assumption, and not just a made up number for a made up phenomenon. 

 

 

 

Knock sensor on petrol engines yes, but this makes very little difference to fuel consumption. 

Edited 7 October, 2019 by TDIum