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We were running our VW transporter on tesco fuel since we bought it in APril this year.  It is a 2008 model, and the manufacturer's instructions state it should not use biodiesel.

We found the van was not really running well, and we switched to Shell.  What a difference!  I am told that the branded stuff has more additives to aid performance and cleaning of the engine.

The difference is incredible, and I dont intend using Tesco fuel vouchers again

Any thoughts?

our mondeo ran like a bag of S**t on the last lot of tesco diesel.sluggish through the gears , smoky and mpg down at around 48 mpg.it seems to vary in quality, sometimes its ok .  the last £20 went in at asda and it goes like hell now so cant weigh it up.probably comes from the same place anyway

tesco is nearer for us and of course the clubcard points and 5p a litre off is the carrot to get you to fill up there

personally i rarely use supermarket fuel as it has too much cleaner etc in it, use either esso or shell but usually twice a year shove a bottleful of Wynns injector cleaner in the tank and that cleans out any crud from the system

only had to use this stuff once and that was on the old proton http://www.youtube.com/watch?v=cY1YndLmbXQ

Petrol has an octane rating, depending on where you get it (main dealer or supermarket) depends on the octane rating and that will efect the car!

Petrol's octane rating is a measurement of the fuel's ability to resist engine knocking. Knock occurs when the fuel-air mix in the cylinder explodes instead of burning in a controlled way. This shockwave moves within the combustion chamber, and creates a metallic 'pinging' sound.

An octane rating is often referred to as an 'anti-knock index'. If fuel has a high octane number, it will have a higher resistance to engine knocking.

Usually, there are three different octane numbers associated with all petrols. Petrol's Research Octane Number (RON) is measured under simple test conditions. Petrol's Motor Octane Number (MON) is measured under tougher test conditions and at higher engine speed and temperature.

The average of these two values is what becomes related closer to actual driving conditions. This value is known as the Road Octane Number, and is what should be used in filling stations.

Occasionally, some filling stations will confuse these different octane numbers in a bid to embellish on their octane rating claims, and advertise their fuel's Research Octane Number, which is higher than the Road Octane Number. In many European countries, the Research Octane Number is advertised on pumps, so a much higher octane value is common when travelling in certain countries.

Hope this helps!

Quote: Originally posted by gaz mc on 14/12/2009

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Saw my next door neighbour at the weekend with a bottle of what looked like orange juice in his hand, he told me it was the dieso he had filled his kia up with the previous week from tesco and had another 50 odd litres of in storage at work what the mech had drawn off, it knackered his car for the week did what ever knows damage and cost him nearly £500 pounds to repair and also the cost of the so called dieso, he was taking the sample to the tesco where he had purchased the dieso after speaking to them once he had got things sorted. I wont be using them again not taking the risk

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Is there anyone who actually knows the truth about branded fuels and supermarket ones?

This had been discussed so many times before so there must be someone who knows if there is a difference??????

Preferably a tanker driver!!!!!

I think it was Fifth Gear that did a series of tests of different fuel grades from a supermarket, Shell and another source. The conclusion was that for normal family cars, all of the fuels were the same, in terms of economy and performance (they didn't mention anything wrong with the running of the car).

The only time it would be better to use a higher-graded (high-octane) fuel, they said, was if you had a serious sports car (they had a Scooby - sorry Subaru Impreza). Then they found one of the branded fuels (Shell, I think) was better than the others, in terms of BHP measured on a rolling road.

PS: they only tested petrol, not diesel.

Didn't they have a contamination issue with Tesco fuel last year?  I think it coudl have been in the South east.

If all fuels come from the same refinery, why no more smoke and better mileage when filling up at a branded fuel station, i.e. BP, Shell etc?

Doesn't all fuel have to conform to British Standards? And do the supermarkets own or run any refineries?  At least at Tesco my Channel Tunnel crossing is paid for with Clubcard points!