I was recently very disappointed with some Tesco diesel that I bought when I was given a 5p off per litre receipt at the checkout. There are a lot of conflicting reports on here, some say that supermarket diesel is cr@p, others say there is no difference between it and branded stuff since both conform to BS EN 590. Anyhows this is my experience -

On Friday I drove 210 miles from Northampton to Sunderland with half tank of Tesco's finest :-) Winds were westerly and light, ambient temperature about 10degC. I drove all the way with cruise at 70mph and stopped once. By the end of the journey my trip computer showed a disappointing 63MPG average.

On Sunday I drove back, with a full tank of Shell 'fuelsave' diesel. Winds were the same, temperature was a slightly warmer 13degC. Again I drove back with cruise at 70mph and stopped once. At journeys end my trip computer showed 74MPG average!

I'm open to interpretations :-)

Difficult to say whether it was totally down to Tesco's finest as there are so many variables, but could have contributed nonetheless.

I often split my fuel between Morrisons and BP (standard diesel) and have never really noticed a difference. My old Octavia, at first, hated the supermarket stuff as it developed a flat spot/stutter around 1,600 - 1,800 rpm

Just shove some Miller's Diesel EcoMax in to boggo supermarket diesel, has much the same effect as BP Ultimate or Shell V-power but it only cost about a quid extra a tank.

Well, I was never a big believer that supermarket fuel was any worse than branded fuel until a few years back when I owned a Vectra SRi 150 (2.2l petrol). The difference in the car's performace depending on what brand of fuel was in it was very noticable. It HATED Tesco petrol which made it quite sluggish and gave terrible MPG (Morrisons and Asda weren't too bad though surprisingly!), Shell and Esso however made the car run really well, quite responsive and gave good MPG. I tended to avoid BP as it was a bit middle of the road performace wise in the vectra and for the extra cost involved I didn't think it was worth it.

I slipped back into using supermarket diesel when I got my Fabia vRS as I didn;t notice any real difference in performance but I have now developed a bit of a stuttering problem which a lot of people on here are saying could be dirty injectors. See my post "Fabia vRS stutter (no, not that stutter, a totally different one)" if you are interested in the details. So I'm now avoiding supermaket diesel like the plague!

I did ask my aunt who used to be the manageress at a Safeway petrol station if different brands of fuel were actually different and she said yes, each brand will use different additives and detergents so I'm guessing Tesco are probably scrimping a little.

Never really noticed any difference between supermarket & branded ,except for the price .

I only use branded stuff, shell or esso.

No difference but then I drive an SDI and put veggie oil in as well.

Its obvious innit. Just look at the globe. Uphill all the way there and downhill on the way back.

I've noticed the same, about 50 miles less to a tank on tescos fuel compared to bp ultimate

I really wouldn't get too hung up on what the trip computer says as far as MPG is concerned.

Get the calculator out...

Its obvious innit. Just look at the globe. Uphill all the way there and downhill on the way back.

I'm not good with sarcasm so I'm sorry if I have this wrong but is this supposed to be a joke or you seriously suggesting if you travel north your therefore driving uphill? Haha Isaac Newton was wrong all those years.

Neither have myself diesel or petrol branded or supermarket

I was recently very disappointed with some Tesco diesel that I bought when I was given a 5p off per litre receipt at the checkout. There are a lot of conflicting reports on here, some say that supermarket diesel is cr@p, others say there is no difference between it and branded stuff since both conform to BS EN 590. Anyhows this is my experience -

On Friday I drove 210 miles from Northampton to Sunderland with half tank of Tesco's finest :-) Winds were westerly and light, ambient temperature about 10degC. I drove all the way with cruise at 70mph and stopped once. By the end of the journey my trip computer showed a disappointing 63MPG average.

On Sunday I drove back, with a full tank of Shell 'fuelsave' diesel. Winds were the same, temperature was a slightly warmer 13degC. Again I drove back with cruise at 70mph and stopped once. At journeys end my trip computer showed 74MPG average!

I'm open to interpretations :-)

AFAIK trip1 only averages "up to" the last 50 miles of a journey. Unless you zeroed trip2 it won't have averaged the whole journey.

You can't really compare outward to return legs.

Though IMO, Sunderland (at the seaside) I'd expect at a lower altitude than Northampton, could be wrong there though.

if you travel north your therefore driving uphill? Haha Isaac Newton was wrong all those years.

If you travel North, From London, up the East Coast your on the Down and if you travel from York, South to London, your on the Up

You have it the wrong way round, North is down, south is up

So you are going up on the down and down on the up

Understand??

Not even remotely accurate, brim it and drive up then brim it and drive back to compare. It's not that I disagree with you but 'half a tank' is pretty subjective. By brimming it you have a fixed point (unless you vent the fill and even then as long as you do the same on the way back it'd be fine). For reference I generally get lower mpg from Asda fuel than I do from Shell, this isn't statistically proven but the last 8k on a tank by tank basis shows an improvement above the running average with Shell and a fall below the average with Asda.

AFAIK fuel is fuel, Asda doesn't have a refinery, neither does Sainsbury's or Morrison's or Tesco's. They all source fuel from the 'local' refinery. If you ever happen to spend any time outside one you'll notice that many different branded tankers come out and go in and you'll also notice that they don't have hundreds of different storage tanks for regular, premium of each fuel. That's because the fuel comes from the same source, the only difference is the additive and detergent package that's included and this is selected by the use of a card given to the tanker driver. He swipes the shell card, he get's fuel and the shell additive package, he swipes Asda's card and he gets fuel and the Asda detergent package. The exception to this is V Power which last I was told they stored on it's own.

I guess what i'm saying is the fuel itself is no different, the 'extras' that are included are what makes it different, shell even marketed the fuel saver as having added ingredients that got you x miles more per tank and i've usually run shell fuel as on anything set up to use 98RON+ it tends to feel smoother.

The riddle master.

Grab a map and read on...

If you read LB123's post he looks to me to be suggesting that if you go north from Northampton to Sunderland as in the OP's question you are going uphill and south from Sunderland to Northampton you are going downhill. I was basically trying to say the compass (polar axis) does not dictate incline.

Not even remotely accurate, brim it and drive up then brim it and drive back to compare. It's not that I disagree with you but 'half a tank' is pretty subjective.

AFAIK fuel is fuel, Asda doesn't have a refinery, neither does Sainsbury's or Morrison's or Tesco's. They all source fuel from the 'local' refinery. If you ever happen to spend any time outside one you'll notice that many different branded tankers come out and go in and you'll also notice that they don't have hundreds of different storage tanks for regular, premium of each fuel. That's because the fuel comes from the same source, the only difference is the additive and detergent package that's included and this is selected by the use of a card given to the tanker driver. He swipes the shell card, he get's fuel and the shell additive package, he swipes Asda's card and he gets fuel and the Asda detergent package. The exception to this is V Power which last I was told they stored on it's own.

I guess what i'm saying is the fuel itself is no different, the 'extras' that are included are what makes it different, shell even marketed the fuel saver as having added ingredients that got you x miles more per tank and i've usually run shell fuel as on anything set up to use 98RON+ it tends to feel smoother.

I completely understand how innacurate the trip computer is. I use Fuelly.com and religiously fill my tank to the vented brim every time. Fuelly tells me that my trip computer is consistently 20% optimistic, so whilst not an accurate measurement of MPG it is still a usefull comparison between these two journeys.

For those who doubt my method I reset the trip computer (trip 2) before every journey.

ROFL about the upward northerly direction :-) In all seriousness though the journey from Northampton to Sunderland involves travelling downhill by about 30 metres - i.e. not very much over a 200 mile journey.

I've read all the posts previously about how all fuel comes from the same refineries, just with different additive packs added, etc, etc, But clearly for me the additive packs seem to have a positive effect. I'm pretty anal about my fuel consumption and i feel I have a keen eye for when the car starts to run poorly - clearly this time it did and I 99% believe it was down to the fuel.

Edited 21 May, 201214 yr by piggoy

I don't doubt the conclusion, just the accuracy of the figures quoted that lead you to it.

My last car was run exclusively on V Power, someone suggested Excellium (Tesco 99) would be worth trying so I did, and noted a drop in mpg, switched back to V Power and up it went again. I also noted the car was less 'smooth', similar story on my old Hornet with full race exhaust, I could run 95RON in summer OK but during winter it would backfire on startup like a shotgun and at 6am that wasn't popular. The compromise was either some Pro FST added to the tank or Sainsbury's 97RON as it was the same price as Shell 95RON.

I rarely get above 50mpg in mine. The only reason i've got an economical car is so i can drive flat out, and get the same mpg as my old astra driving like a grandad!! lol

I really wouldn't get too hung up on what the trip computer says as far as MPG is concerned.

Get the calculator out...

+ 1 on this, 74mpg at 70mph seems rather optimistic to me

If you travel North, From London, up the East Coast your on the Down and if you travel from York, South to London, your on the Up

You have it the wrong way round, North is down, south is up

So you are going up on the down and down on the up

Understand??

If you travel North, From London, up the East Coast your on the Down and if you travel from York, South to London, your on the Up

You have it the wrong way round, North is down, south is up

So you are going up on the down and down on the up

Understand??

likewise, on the west coast, going from Glasgow to London, you go up.From London to Brum ,you go down.

But then ,Mr Goldfinger ,he talk choo choo talk .

there could of been more uphill driving on the way there? saying that i only use branded fuel as i seem to get more miles for the litres i put in. plus morrisons uses something like 7% biodiesel in theres. ive been told that shell and big brands put more additives in to make the fuel better. hence why there always a little bit more expensive than the supermarkets maybe?

I try to avoid supermarket fuels myself as I tend to find it doesn't run as smooth or sluggish, both petrol and diesel. esso/shell for me is couple of p off at most anyway. £1 difference per tank isn't worth losing sleep on.

Surely your engine likes a consistent quality of fuel? I bought my VRS in September, since then I have put 6k miles on her. All with BP ultimate diesel.

When I first got the car it would smoke quite a lot when I booted it, but now I get barely nothing. The engine got smoother and smoother and my MPG's increased.

Constant switching of fuel quality/supplier will only throw off your ECU slightly? Don't they "learn" about fuel quality and climate to optimise the running of the engine?

AFAIK trip1 only averages "up to" the last 50 miles of a journey. Unless you zeroed trip2 it won't have averaged the whole journey.

You can't really compare outward to return legs.

Though IMO, Sunderland (at the seaside) I'd expect at a lower altitude than Northampton, could be wrong there though.

Trip 1 records constant unless the car is stationary for 2 hours then it resets itself, otherwise it keeps running regardless of miles