Advice on petrol

[Len]

I use Red X injection cleaner. Far Better!

[mrwotto]

i used to use optimax, in my mk3 16v, but seen no difference at all, so i am now using the normal stuff from my local asda, which i must add comes from shell, as i live quite close to the refinery at slanlow, and see the tankers coming in all time to fill up.

[...joe]

optimax is the highest octane fuel you can get in this country without adding anything to it. it makes a hell of a difference to high performance cars but for day to day driving it is probably not worth the extra expense. it does burn out deposits and crap from your engine so if you've got a high miler it may do more harm than good as it can burn off carbon deposits round your valve seats that were sort of plugging gaps and make your car smell and smoke a bit. but if you want performance out of a well tuned and tight engine you will definately notice the difference. i know alot of people with caterhams and they all go out of their way to get it.
oh and i used to work for shell around the time they launched it so have read all their inside info and test reports on it and it is proven to make a difference. which is why people use it when they are doing quarter miles, or rolling road sessions as you can see the difference. it may take a few tanks before you notice the advantages.

[...joe]

Apparently Esso Premium 97 is the best, followed by BP Ultimate then Optimax.

other way round mate optimax (99 ron), then ultimate ( 98 ron) then esso (97 ron)

[rubjonny]

Apparently Esso Premium 97 is the best, followed by BP Ultimate then Optimax.

other way round mate optimax (99 ron), then ultimate ( 98 ron) then esso (97 ron)

I don't mean best as in how much Octane, I'm talking quality here!  This was from an independant fuel tester bloke, for whatever that's worth.  Its worth noting that Optimax will loose its Octane over time, not a problem if the station is popular and is refilled quite a lot...

[rubjonny]

OK I found the quote, make of it what you will:

I work with petrol companies, so i'll let you into some lesser known secrets.

Super unleaded is a fine fuel, but only if purchased from reputable dealers. Esso SUPER, like BP are about the best you can buy. Supermarket stuff is just 4 star without the valve additive, which itself is just 95 unleaded that has been octane boosted. AVOID AT ALL COSTS. Supermarket petrol is a very dirty fuel. Any engineer of their pumps will confirm that.
I have seen the results of their filters and you get everything from feathers to god knows what flowing through supermarket fuels. EVEN SAND.

All Super by law has to be 97 ron, but where its stable enough to hold higher octane, stations are able to advertise its octane as being higher sometimes.

Optimax has a variable octane rating, due to its structure its less stable, but leaves the refinery at 101 octiane.
Thats the equivalent to the old 5 star for those old enough to remember it.
By the time you buy it, its closer to around 97.
This is why its octane isnt always stated.

Normal 95 or 97 fuels wont lose octane, whereas optimax does, but used fresh, its the highest octane fuel you can buy.
 

All supermarket fuels come from either the Matex or Purfleit refineries for the south east. These only take oil from the eastern block. They are most definately NOT the same fuels as ESSO and such like.
They also remix contaminations for other companies then sell the fuel on via supermarkets as well.
On average, each 50 litres brought from a supermarket will have 8% contaminates, and 9 grams of grit.
I have got 2 test tubes sitting on my desk at work of both ESSO and Tesco regular 95 for simple comparisons when arguing these points with supermarket buyers.
There is a bead in both which on the Tesco tube floats in mid suspension due to the grittiness of its petrol.
The ESSO falls straight to the bottom.
These are random samples taken every few weeks, and the results are always the same.


Texaco is a subsidary of ESSO and both use the same petrol.

There are basically 3 companies which supply fuel to the UK. ESSO, BP, AND SHELL.

Each sells to all the other names you find.

JET, FINA, Q8 and a few other smaller outlets all use SHELL.

TEXACO and TOTAL use ESSO,

Supermarkets use Eastern Block fuels, which are primarily designed for the 91 Ron continent market.
These are upgraded in the UK to UK specs by using Butane gas.
Hence to avoid.

BP Ultimate is just its old Super grade cleaned up a bit.
IE. It goes through another filter at the refinery.
Not a bad fuel though, second only to ESSO in quality.
Its Diesel is the best in the world for all you Diesel owners.

OPTICRAP. Need i say more. All grades supplied by Shell.
Might as well fill from your local FINA station and pop a bottle of Halfarts octane super duper booster plus in.

ESSO 95 and 97 = If you want every pennies worth in quality petrol, look no further.
Get it at your local TOTAL, TEXACO or ESSO now :beer:

[gibby]

Thanks for all your replies, interesting how many different opinions there are on such a simple issue.  The upshot of all this is I'm non the wiser  I reckon normal unleaded might be the way forward for me as mines got 108,000 miles on the clock anyway but I liked the fact that Optimax is supposed to clean as it goes.