Superspark is dead right with his comments. Years ago, supermarkets were guilty of selling rather raw petrol and diesel, it would burn but was very dirty. The OEM's had a meeting with the supermarket people, some time in the 80's. I can't remember exactly. Anyway, the supermarkets agreed to supply fuels to an acceptable standard, to stop the OEM's putting a note in car handbooks that supermarket own brand fuel was not recommended.
I was involved in fuel and oil additive development then, as a tester, not a formulator.
And so it came to pass, that supermarket fuel became much better, and you can use it safely.
There was still no additive package as good as that used by Shell though, and now I have retired from that work, I have no reason to doubt that it has changed.

Dave wrote:

ad210358 wrote:

where as yesterday at Todhills £1.31.9 but BP on the south side £1.36.9 how can two garages opposite vary so much

Hmmmm, they were £132.9 on sunday when I stopped to fill up

They're also different prices coz southbound is BP, and northbound is Shell

I bet you were gutted over that
What carriageway has nothing to do with, if BP were northbound and Shell southbound the BP would be more expensive, BP is consistantly the most expensive of all the branded fuel  p****d off with a Digital Keyboard Warrior

I suspect it's down to the additives. Supermarkets will sell to the minimum standard, and better additives will increase the cetane raqte of diesel and therefore the mpg. By the time you've got all your loyalty points the supermarkets are much cheaper, but if you want the quality you have to add your own additives - Millers, or the famous 2-stroke oil. Oddly enough my current tank is giving me almost my best ever consumption - 41.7mpg after 450 miles according to the computer, and that's Morrisons at Morpeth with a shot of Morrisons own 2-stroke.
Btw regarding an earlier post, higher octane petrol is less flammable. That's why it doesn't knock.

Considering some people run their cars on old chip shop oil, I think supermarket diesel is the least of the problems!

But the people who run on chip oil don't normally check the mpg. And although it's fine ina TDi please don't put it neat in your FL2 - it won't like it. Biodiesel properly made from old chip oil has a higher cetane rating, so will give you better mpg. And probably won't f*** up your engine. Probably.

Fair enough, but with all the mayhem and disasters in this world, I aint gonna be loosing a lot of sleep over Supermarket v. branded diesel.

As with all oil based fuels there are harmful depoites that will build up in your engine from the moving parts of the fuel pump to the high presure injectors. The only safe way to help keep moving parts of pumps and fine spray injectors is to add your own additive.
This will help to keep parts in tip top condition. These additives work by desolving the deposites that build up, A cleaner if you like. Where injectors are concerned, the tolerances are very precise and it want take much to upset the balance causing miss fire in extreme cases and more expence for you in the long run as you will get less miles per tank. Boats have the same problems when fuel is stored in the inboard tanks for 12 month or more so there are additives to stop the fuel from braking down and gumming things up.

Sorry Past Master thanks for bringing that to my attention...I got completely confused when I was writing it! Mine: 2012 Golf GTI Edition 35
Family's: 2009 Freelander 2 HSE TD4 Auto, Stornoway

Yorkshire - God's County

You're welcome. And I wasn't trying to score a point - a lot of people genuinely don't understand that one (burns slower, goes faster wtf?).

Unless things have changed in recent years, I can tell you how it is. (Or at least was )

All the fuel originates from a chain: refinery -> tank farm -> tanker -> fuel tank. At the tank farm tankers from supermarkets lift oil from the same tanks that Shell, BP etc do. No difference.

IMO anyone who buys from Shell or BP or whomever rather than cheaper supermarket stuff (sometimes it isn't cheaper!) is just wasting money.  Brian

MY11 FL2 SD4 GS
Extras to same spec as XS apart from the Satnav, plus Xenons.
Ipenema Sand, Ebony.

Talking to one of the major fuel supply tanker drivers when he was delivering I asked about the difference between fuels for supermarkets and Shell, Esso, BP

"you are given a bucket with some additive to pour into tank before filling and it depends on which brand as to what you get"

This was 10 -12 years ago. possible more scientific by now. All FL2's (3) Gone
2011 Mercedes C180 CGI Gone
FL2 GS Auto SD with heated leather, factory tints, alloy spare and a few other bits.

I seem to get the best value out of 'cherry'  freelander 2 SE black and beige - now sold

s7gpt wrote:

I seem to get the best value out of 'cherry'

its 65p/l plus vat  At work
At home

"I can't always believe facts I read on the web" - Charles Dickens

winner by default of the tractor vs caravan race

I have been told (an inside source) that supermarket fuel pumps are calibrated to very very minimun allowed.
Trading standards check pumps regularly and there is a tolerance within which you must fall. This may also be the reason for lower comsumption figures.
You are NOT short measured just receiving the neatest ammount allowable. All FL2's (3) Gone
2011 Mercedes C180 CGI Gone
FL2 GS Auto SD with heated leather, factory tints, alloy spare and a few other bits.

From Leics Trading Standards site "By law the pumps are required to meet stringent requirements for accuracy to ensure that any errors in the amount of fuel dispensed are within certain tolerances. This means that a petrol pump can deliver up to 10ml extra per litre of fuel and is only allowed to deliver 5ml less per litre of fuel - and bear in mind that a teaspoon is approximately 5ml."

That's +1% and -0.5 % allowed..... which should mean MPG calcs have the same tolerance.

Trading Standards regularly check the pumps all over the country.