What do Tesco do to their fuel??

Moto2

timbo58 wrote: »

I also agree with Moto2 that only a decent JASO specification 2 stroke oil is worth having although 'horses for courses' an older classic bike really only needs [strike]a quality semi synthetic oil[/strike] Castrol R

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Joe_Horner

The additives are a red herring though.

When they design a car / engine, the only thing they can rely on about fuels are the various standards, nothing more and nothing less. Just like in my earlier analogy, the only thing a TV company can rely on about an electricity supply is the standard in terms of voltage and frequency. That's why they're known as "standards".

It's also what the car makers use to tell owners what fuel is acceptable - check your handbook and you'll see that it tells you to use fuel meeting EN (petrol or diesel as aplicable).

If a manufacturer designs an engine that is going to suffer premature faults, run poorly, or (in the case of excess smoke) quite possibly break legal emission requirements, if it's used with fuel that meets the standard they specify then that's a bad design.

It doesn't matter whether or not it runs better on other fuel - it has to run according to their stated performance on that minimum standard fuel.

In which case, if it suffers flat spots and excess smoke on that fuel then that's how they designed it and I'd strongly suggest buying a different car next time rather than different fuel!



eta: Incidentally, Euro fuel standards are far higher than those in many other parts of the world where these same engines are happily used on whatever local muck is available.

DigForVictory

Tesco have form for something nasty in their fuel - they didn't have to pay out a couple of years back by accident.

A mate who works for HMRC in the Road Fuel Testing Unit won't use Tesco fuel. He says it's like really cheap teabags - you get the "scuff off the floor as well as the remaining scraps of tea". So there are standards, and apparently Tesco skirt just above the very bottom of them.

Me, I don't use them as the local pump is 6 pence more per litre than another supermarket on the commute to work.

Joe_Horner

DigForVictory wrote: »

So there are standards, and apparently Tesco skirt just above the very bottom of them.

But the whole point of standards is that they're an objective test. Something either meets them, in which case it's ok, or it doesn't, in which case it isn't.

"Skirt just above the very bottom" still equals "meets the standard", so a car sold as requiring fuel that meets that standard standard should not play up when it's used.

If it does play up then it's a design problem with the car, not a quality problem with the fuel.

bigjl

Lets not forget that vehicles can adapt to poor fuel, such as when travelling to countries in Europe that have inferior fuels such as some Eastern European countries.

The reason for lack of power is likely down to the vehicle itself reacting to the poor quality of the diesel used and knocking back the power to protect the engine.

As far as 2 stroke oil in diesel goes apparently it is best to use semi synth or conventional as there is no benefit to using the really pricey stuff.

200:1 is the point when benefits tail off.

And also it must be low ash.

Don't forget that Mercedes Benz did an expedition with several diesel vehicles and one thing they did do was add 2 stroke to help avoid issues with poor quality diesel fuel.

Joe_Horner

bigjl wrote: »

Lets not forget that vehicles can adapt to poor fuel, such as when travelling to countries in Europe that have inferior fuels such as some Eastern European countries.

The reason for lack of power is likely down to the vehicle itself reacting to the poor quality of the diesel used and knocking back the power to protect the engine.

Hadn't forgotten that but you still seem tobe missing the point.

Say, for example, Wolkswargon Car Company produce an engine. In the specifications they say it produces 350BHP in UK spec. They also say that you should use fuel to EN standard.

No mainstream maker recommends using fuel that exceeds that spec because they'd have to specify which parts of the spec should be exceeded and by how much.

Even if they did specify "exceed" and by how much, BP, Esso, etc don't publish technical details of what areas of the spec their fuels exceed, which means you'd never know whether the fuel you're using was ok for that car or not.

So, provided you use fuel to EN standard, then the specified output (give or take manufacturing variations) is what you're entitled to expect. It also must meet emission requirements - including smoke / particulate limits - on that fuel or it would never have gained type approval.

You may get better performance using fuel that exceeds the standard in some way, and you may get reduced performance if you travel abroad and fill up with donkey wee. But that's entirely different to the car running "poorly" on the specified fuel.

GolfBravo

bigjl wrote: »

Lets not forget that vehicles can adapt to poor fuel, such as when travelling to countries in Europe that have inferior fuels such as some Eastern European countries.

And how are their fuels inferior? They must meet the same standards: EN 590 and EN 228.

missusjen

Water. If there is water in your fuel then your car behaves like that. It happens occasionally, but it's a real pain.

Richard53

I've had this debate too many times, so I'm not up for an argument here, just to relate my experience. 2006 Mk 3 Mondeo Tdci. I normally fill it with Murco (close to home, convenient, nice people, only 1p/litre more than supermarket) but occasionally I fill up in Tesco. Sometimes the car runs rough for the whole tankful and I lose 3-5 mpg on the fuel readout. When I fill it again, within a few miles it is back to normal. Here's the facts: it doesn't happen often, and it doesn't happen every time I fill up at Tesco, but every time it has happened has been on Tesco fuel. It has never happened on other fuels. There's enough evidence there to make me think that the Tesco fuel is to blame *when* it happens. I reckon the arguments about standards and additivies are missing the point. I'm sure the fuel and whatever they put in it are complaint with the relevant regs. Water or other contamination seem a much more likely cause. But I avoid filling up at Tesco unless I am desperate.

Westmead_Fan

whats the difference between Tesco petrol stations & the Esso with Tesco express stations because i thought they are supplied by the same people?

someone told me that the difference between Tesco fuel is that its older fuel, but who knows if this is true.