Supermarket fuel

[mike(liverpool boys)]

My girlfriend drives my 1.2 clio to work 5 days a week every week. Its,around a 64 mile round trip per day.

She has always filled it with morrisons supermarket fuel for almost a year now and always averaged around 46 mpg, but a couple of weeks ago I read in a magazine that supermarket fuel can be of a lower quality. So I noticed that the ESSO garage next door to the supermarket was at the same price so asked her to fill it there and see if there was any difference.

So,3 tankfulls later and the onboard computer is now giving an average of just over 50 mpg and my maths on the last tankfull came up with 51.2 

My question is,can supermarket fuel really make that much difference??? And why would anyone have a diesel when a petrol can do that kind of mileage for 5p a litre less???

[Steve Pyro]

....which is why Shell / Esso / BP etc 'ultimate' fuels are generally rated as being better for your engine by the likes of http://www.honestjohn.co.uk/ etc.

It used to be a case of you get what you pay for, but now there's not much of a cost difference between supermarkets and the majors.

Mrs B runs her Monaro on 97 or 99 octane Shell or BP and gets over 30 mpg - from a 5.7 litre V8!  (and she drives it like she stole it).

[landman]

I've had my S-Max now for 2.5 years and have tried every fuel permutation.

The engine is the Volvo B5245T2 unit [5-cyl 20-valve 220 bhp] unit similar to the Focus ST's unit.

To my mind there's no difference between supermarket brands & "known" brands, and indeed no difference between 95 RON and 98 RON.

By way of example I filled up at Auchan in Cherbourg this year & got a tank of 98 RON fuel at "only" £1.15/litre.

Drove to LM & back, a distance of 380 miles.  I averaged just under 27 mpg with 3 pax onboard & a full-ish boot.  Kept pretty close to the speed limit, so nothing to draining on the MPG.

Frankly I'd have expected more like 30 mpg under those conditions and reckon that 95 RON would have given me the same returns.

The only fuel my car doesn't like is Esso, it pinks like mad.

So my answer is that mebbe the Renault doesn't like Morrison's fuel, and will perform better with [almost] anything else.

As to the diesel question that's very simple.  If you drive <12,000 miles a year you should not buy diesel.  You'll never get your money back. 

The slavish adherence to "must buy diesel" mantra is false in the UK. 

I know people who have bought diesels in Jersey and wonder why they have problems with the Diesel Particulate Filter.  The DPF needs constant speeds to work, something not possible on Jersey!  They bought diesel because they holiday in France once a year!!!

Just remember that petrol emits CO2, which will affect the quality of your life, whereas diesel emits NOx, that will shorten your life.

[Nordic]

The increase in MPG may be as a result of more careful driving, if you start watching for mpg then you will find it gets better.

You need to do a blind test, just fill the car up and dont say where you got the fuel then check the results.

We did use to have a Zafira that had ecu problems that was fixed under warranty. The Vauxhall garage blamed the the fact we used Tesco fuel.

[Lorry]

Supermarket fuels are believed by some to have low octane issues.  If your car can cope, the better bang of lower octane will give better power and MPG, until the anti knock sensor surrenders (if you have one).  Many Subarus went straight on to limp home mode, and some engine experts like SBD say don't go near the stuff.

They all keep quoting RON, but never "calorific value" - its a cover up because it varies.

I hear that French fuel has more bio in it, and opinions vary as to whether you get more bang per buck.  Again, I think it varies

Tesco 99 does seem to have more power, but I can't yet see that 99 RON race fuel is much different

[Grand_Fromage]

Petrol is bought and sold as a standard commodity. The petrol at any given forecourt could be from a number of sources. It all meets a specified minimum quality and that is about it. The premium grades have very small quantities of additives that the oil companies use as an excuse to hike the price.

The bottom line is that the forecourt-to-forecourt quality variation in fuel from one supermarket chain is likely to be as great as that between one name brand and another. They buy fuel from the cheapest source of the moment, and in a given area of the country all the fuel sold on any forecourt often comes from the same depot whatever it says on the side of the tanker.

Bottom line is that discussion of the benefits or hazards of fuel of different brands is a fairly pointless. One thing that I would say though is that the tanks in supermarkets tend to be younger than those in long established filling stations and consequently less time has elapsed for the accumulation of contaminants.

GF

[6 Euros - JD]

This article is worth a read.

http://www.thorneymotorsport.co.uk/tuning/Fuel_Test_Results_Update.shtml

Interesting findings especially as regrads storage time.