Quality Fuel vs Supermarket fuel - what's the real truth?

[The_Laird]

There was a question on this in the motoring pages of the Sunday Times yesterday and the reply was adamant that supermarket fuel was just as good as the premium fuels from Esso and BP, with only Shell giving more mpg. They were also adamant that all the fuel comes from the same depots and only the additives make it different.

BUT... in a conversation recently with the guru of all things motorised (sometimes known to we mortals as Ben) he suggested that supermarket fuel is often close to its sell-by date and nasty stuff is added to make it meet the required standards. And the nasty stuff is bad fior your engine.

So, is the truth with Ben or The Sunday Times - anyone have inside knowlwdge?

[Zip]

My father is ex 36 years with Shell, so you would argue is maybe slightly biased....

However, wisdom holds that fuel only "goes off" when it's sat in the tanks under the forecourts for too long - I understand that the octane rating actually drops over time as stuff evaporates. The majority of supermarket fuel is turned around very quickly, and hence, is perfectly "fresh".

Yes it is all shipped from the same depots - my father ran Stanlow refinery in the late '80s. And was a shift managed at Buncefield Depot in the 70s.

It is, as you say, all about the additives - and Shell is (currently) doing it better than anyone else.

Zip

[ainarssems]

One thing is additives used like cleaning agents.
Other thing is that good stuff like shell is supposed to contain higher percentage of light hydrocarbons which evaporate faster and more easily making fuel to ignite and burn faster improving efficiency reducing emissions and carbon buildup in engine. Also helps in cold starts.

I have done some testing back around 2001-2002 when I was living in Denmark comparing regular stuff to Shell optimax and did feel increase in low and midrange torque and fuel consumption went down a bit making the costs around same in the end. I have only used Shell optimax and now v-power since.

I have done a fair deal of blown head gasket jobs for friends and a couple on my cars some bought with blown head gaskets to fix and sell for a profit. Normally You get quite a bit of carbon build-up in the compression chamber on the head and piston. I have taken apart also my S8 engine due to loss of compression in one cylinder ( it turned out I did not have to take head off because it was down to 2 damaged compensating pieces for valve clearance adjustment causing 2 of the valves not to shut properly but that's another story). I do not know what fuel have been used in it before me but I have done around 8000 miles using shell v-power before taking it apart and there was no carbon build-up at all. Piston tops and compression chamber were only brownish colour with out any build-up. There was some in exhaust ports and manifolds like You normally get. This have increased my confidence in shell fuel.

[christhompson]

Here in France the difference between supermarket diesel and Total Excellium is [minimum] €0.08 per litre and often more - so a little less than 10% extra. I reckon to get around 5-6% better mpg and the car behaves much better throughout its power range, but particularly low end torque. I also don't bother to put in fuel system cleaner any more, so I guess it comes out about even.
Also - if you're a member of Club Total they give you 15 days breakdown insurance for each fill of a minimum of 30 litres. Easy!

FWIW the Daily Telegraph's motoring correspondent, Honest John regularly recommends Ultimax

and item 4.12 of this article http://miniwww.tripod.com/gasoline.htm#9 seems to offer an answer