When I had my Freelander 2 which I bought at 4 years old but with 132,000mls on it I tried BP Ultimate in it for a few tankfuls compared to my normal Sainsburys "city" diesel. I found my MPG which was normally around 44mpg (Manual gearbox) had dropped back to around 42mpg and i wasn`t getting the same miles from a tank as i would normally. Another annoying issue was that at idle the engine would hunt and was prone to stalling. Going back to the cheap city diesel and the MPG went back up and the idling went back to being smooth as it had previously! Go figure as they say!

Don't modern engines and ECUs calibrate/tune themselves for different fuel quality? Although I wouldn't have thought that it took a couple of tank fulls do it? 3 x FL1 2 manual + 1 auto
5 x FL2 4 manual + 1 auto
Now Discovery Sport P250 MHEV SE

Its all a bit like those of us who are into detailing and buying lots of expensive cleaning products. If it makes you feel good then why not. Nothing wrong with all that and yes its nice to have a clean and shiny vehicle.

But when Ive come to sell my cars, nobody has ever asked me how and with what Ive washed them.

Buy expensive fuel if you want and it makes you feel happy - it wont do any harm. But as far as I can see there is no evidence to say it will reduce the risk of expensive bills and I doubt any future buyer will care what fuel you've put in it even if you save all your V Power receipts.

In the past Ive tried 2SO (bought a load of it) in both my BMW and Fl2 - saw no short term benefit and didnt keep either car long enough (only 60K miles) to see a long term gain so gave up carrying it around.

Ive tried a catch can too on an Octavia VRS tdi. The car's oil separator did its job very well and as far as I could tell 99% of "caught" stuff was dirty condensed water not oil. Maybe on old cars with worn piston rings and valve seals you get more oily blow-by but on a modern car the catch can seemed a waste of time and would not have much effect on inlet port cleanliness. Jules

My understanding is that diesel fuels have cleaning chemicals added to them. V-Power may have some extra powerful cleaner added but even so it would only clean the fuel lines, fuel pump and injectors.

Interestingly some petrol cars have direct and port fuel injection and so its possible the fuel could clean the inlet track and inlet valves too. Jules

dorsetfreelander wrote:

Don't modern engines and ECUs calibrate/tune themselves for different fuel quality? Although I wouldn't have thought that it took a couple of tank fulls do it?

jules wrote:

Nodge68 wrote:

Whoever wrote that doesn't have a clue about how a diesel works...
Yes I agree - the motoring press is full of unreliable information


As to the question of premium fuel being better? Well it depends on how the engine is being used.

Diesel fuel is dirty stuff when it's burnt, so does produce lots of carbon fouling, especially in the combustion chamber and exhaust system. This is especially so when the engine is used at low power outputs, for extended periods of time, motorway cruising being an example of that. Under these conditions, the gas velocity through the combustion chamber and exhaust is low, which gives the carbon deposits (soot) a chance to cling on to surfaces, and slowly build up. In this instance, premium diesel fuels help as they normally have decarbonisation additives to reduce this build up, which helps maintain engine efficiency and power.

If however the engine is used at full power for much of its operating cycle, then the gas speeds through the engine are higher, which prevents the carbon fouling, and actually cleans out carbon built up in a previous low power operating cycle.

Thats interesting - you are saying the speed of diverted exhaust gases through the EGR unit is what keeps the EGR unit clean. I always thought a diesel produced more soot when under load because in order to to produce more power, more fuel is injected and the fuel to air ratio increases which in turn produced more carbon particles as combustion is less complete . Conversely at light loads the fuel to air ratio is low so combustion is more complete and less carbon is produced.


During the monitoring of my EGR valve Ive noticed that it opens most when I accelerate. When cruising at motorway speeds its not open much at all. It seems to me that more EGR occurs in stop/start town driving than motorway cruising.

I would occasionally use BP Ultimate in my FL2 diesel and it 'seems' to give better fuel consumption, but I haven’t really compared like with like, i.e. the same journey but different fuels. However prior to the FL2 we had two petrol Volvos - a C70 2.3 high pressure turbo and a V50 2.5 low pressure turbo. With the V50 there was absolutely no difference between BP Ultimate and Tesco regular but with the C70 the difference was very noticeable. The engine was much more responsive and smoother, and it regularly gave 10% better fuel economy. We don’t have Shell fuel over here in Norn Iron but the BP Ultimate is comparable to V Power I would have though.

I used, Shell V Power for a couple of years, 30.2 MPG. I have now just gone on to the standard Shell 30.2 MPG.
I will not, unless under extraordinary circumstances use, Super Market diesel.

I thought my 36 mpg average reading was low , but you must really be booting yours to get thirty.

I find the diesel from Costco is good. We've swapped a couple of years ago to it and at the time we had a Hyundai Terracan, which ran noticeably better with it. We've stuck with it ever since. The other advantage is that it's cheaper too!

Coming late to the party.
I too only use premium fuels. In fact there is a premium fuel coalition and quality bar that must be met. Cannot remember the name just now.
Whether it be a diesel or petrol engine, over the long term the benefits are clear (lol, pun intended). Fuel systems, combustion chambers, turbos , cats are cleaner. And that leads to less troubles on starting and running.
Even my lawn mower runs better.
As does the Volvo diesel in the boat. Starts like a charm after 30 years.

As a result I have not ever had the need for a cleaning/additive service.
For any of you that have ever performed a carburetor service, there is quite the mess left by dirty fuel. Guy Pensa
Cars with Personalities
Getting itchy. What's next?
2014 Land Rover HSE Lux (blend of practicality and aggressiveness)
2007 XKR (Jaguar Racing Green) (woo hoo!)
2004 XJR (Jaguar Racing Green) (deceased)
2002 S-Type R (British Racing Green, of course)
1951 Riley RMD (Black, time for that restoration)

Not directly related, but I don't use independent outlets anymore. Not sure if that's the same as your supermarket brands, but they broadly comprise anyone outside the big brands.
A small independent in my village was caught selling souped up heating oil as diesel - caught after a semi trailer engine was destroyed. That was a very expensive bill before being tracked to the retailer when his tanks were dip tested.
Now it's BP, Shell, Caltex (soon to be Ampol). I do prefer the premium diesel - get a bigger discount at Caltex too. MY11 SD4 SE Auto

There are several issues here.
1) Are big name branded fuel stations better quality managed than large chain supermarket fuel stations or small independents.

In the UK we have very good fuel quality as a rule. Occasional disasters due to mis-filling of the underground tanks or sediment ingress are rare and I believe randomly spread across filling stations brands. However I personally avoid small independent "village" filling stations as they generally have a low turn over and that makes the chances of me having a fuel problem, before the issue is noticed, more likely.

2) Does branded "performance" fuel offer any benefits over branded standard fuel.
Show me credible evidence. The manufacturers are very loose on their assertions so they cant be held up for false advertising.


Fuel quality can vary considerably around the world so the issues may vary between countries. My opinions are based on my UK experience. Jules

When I was at work (eight years ago now) our sites had there own fuel tanks. When the Bio Diesel was introduced we had problems with black organic stuff actually growing in the tanks. I don't know if fuel stations have the same issues. 2007 TD4 XS The work horse that earns its up keep
2013 SD4 HSE The posh one for towing the caravan
1973 Triumph Stag I bought in 2009 and restored.

My experience with supermarket fuel is with petrol, I have had two motorbikes go around the clock using ordinary unleaded supermarket fuel with no issues. 
Hung like Einstein, smart as a horse.