Premium / regular / supermarket petrol - what's the difference?

[nilagin]

I've personally not had a Petrol car, ever actually now I think about it, but I do tend to make a conscious decision to avoid supermarket diesel (more so now with the Mercedes), I certainly seem to get more miles out of Shell, BP or Esso fuel than my local ASDA or Morrisons.

A few years ago the percentage of biodiesel content in diesel fuel was increased, supermarkets sell the higher biodiesel content fuel whilst most of the big name fuel companies continue to sell the lower percentage fuel. The latter giving better mpg.

 

[Mr Bump]

I used to put loads of veg oil in my C3 1.4HDI when I had it, must be about 8 years ago.
you used to be able to get those massive 10l plastic containers full of it for buttons from makro.
me and my mate syd used to load up the boot every few weeks.
it didn't half smell crispy

 

[andya700]

I've personally not had a Petrol car, ever actually now I think about it, but I do tend to make a conscious decision to avoid supermarket diesel (more so now with the Mercedes), I certainly seem to get more miles out of Shell, BP or Esso fuel than my local ASDA or Morrisons.

If you make a conscious decision to avoid supermarket fuels, then how do you know that the fuel consumption is different?
To ascertain accurate fuel consumption, you have to use a certain fuel for a sensible amount of time in different conditions, which means using it regularly.

 

[chrism_scotland]

If you make a conscious decision to avoid supermarket fuels, then how do you know that the fuel consumption is different?
To ascertain accurate fuel consumption, you have to use a certain fuel for a sensible amount of time in different conditions, which means using it regularly.

Poor wording, I should have said that I now make a conscious decision to avoid supermarket fuels, after many many years of using supermarket and non-supermarket fuel

 

[FJ1000]

All 3 of my cars are remapped, and have to be run on 99 RON fuel. Running on lower octane fuel causes the ignition timing to get pulled, meaning less power and efficiency. Specifically on my RS4, it also begins to run a bit lumpy on the rare occasion I've had to put in some 95 RON.

Well known Audi tuners MRC tuning actually prefer Tesco 99 to the shell equivalent. These guys will know - they have an enviable reputation, and tune cars all day everyday - stuff like 900hp RS6's!