A question of petrol?

Back in the early 1970s there was a real threat of petrol rationing and, consequently, lots of advice about how to conserve fuel and get the best mpg out of the allowance.

Fortunately rationing never came in, although a blanket speed limit of 50mph did which is why many of us who were around then will say, when asked, that that is the current speed limit on single carriageway roads!

But I digress.

One piece of advice was to mix brands of petrol at each fill up and not to stick to one single brand.

For some time, in a 2012 Nissan Micra, I have been getting around 55mph on the journey between Manchester and London on Motorways using solely Shell Fuelsave as that happens to be what my local garage sells.

Having to travel around more recently, I have been filling up wherever petrol is cheapest and the tank now contains, in varying proportions of course, a mixture of Tesco, Asda, Morrisons and Shell and on a return trip between Manchester and Penrith, again on Motorways, I averaged 61mph driving in my "normal" style.

Does this prove that the old advice to mix brands was correct or is this merely the result of other external factors such as weather, hills encountered, etc.?

Are some fuels better than others (if so which) for mpg or is it all hogwash and they are all, to all intents and purposes, the same?

Thanks in advance.

My motor has a right hissy fit with BP fuel the 97 RON stuff and normal unleaded, in fact she has a hissy fit at anything other than Tesco Millenium 99/100 RON / Shell Optimax 98 RON.

.......and I always felt my van had more ooomph with the better diesel and smoked less when flat out.

as regards to mixing fuels, thats a new one on me, surely everyone mixes fuel unless they stick with one brand only!

Petrol's are not all the same.... differing levels of refinement and as above the RON/OCTANE varies too.

My former motor had to have minimum 98 RON according to manufacturer and if I didn't bother you could tell..
it didn't like supermarket petrol either even if the correct octane !

the amount of small capacity bikes that i get paid to 'fix' as they get really sluggish, hard to start then eventually dont start at all.
first question i always ask is where was the bike filled up? - if the answer is supermarket fuel station, all i do is drain it out and refill with BP fuel (as we have a BP at the end of our road) and the bike goes back to how it should be

That's funny coz I thought all fuels wher refined in the same place from the same oil .
and only the additives where different .

yeah, as far as i know they are refined in the same places but is 'graded' - supermarkets just buy the low grade fuel and dilute with more stuff (like ethanol)

Thanks for the responses - still no definitive answer about the efficacy of mixing fuels!

ViSaGe: as regards to mixing fuels, thats a new one on me, surely everyone mixes fuel unless they stick with one brand only! indeed fuels are mixed unless bought at the same chain. My Old Man, alas with us no more, back in the 1950s and 1960s would only ever fill up with Mobil (or MobilOil as it then was) as he believed that that was the best petrol. I generally always fill up with Shell FuelSave because that happens to be what my local garage sells but when I was travelling for work I filled up with whatever was available when I needed petrol and I had no brand loyalty. I know of neighbours who only ever use Tesco as there is a large supermarket nearby. I'm not sure that mixing fuels is the norm, but then I have no evidence for saying that.

Still no answer for you, but I do remember a few years back when I used to fill up in either a Shell or a Morrisons.
The car used to struggle with the Morrisons petrol, it happened every time for it to be considered anything else!

Now days I try to only put BP into the car, mainly for the Nectar points over anything else.

Quote:

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Originally Posted by iBozz

For some time, in a 2012 Nissan Micra, I have been getting around 55mph on the journey between Manchester and London on Motorways using solely Shell Fuelsave as that happens to be what my local garage sells.

Having to travel around more recently, I have been filling up wherever petrol is cheapest and the tank now contains, in varying proportions of course, a mixture of Tesco, Asda, Morrisons and Shell and on a return trip between Manchester and Penrith, again on Motorways, I averaged 61mph driving in my "normal" style.

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That's your answer.

Personally I stick to the Shell stuff - the FuelSave diesel has a higher cetane rating than the V Power Nitro which makes diesels run smoother. The car definitely feels perkier and is more free revving on V-Power, but on the motorway I seem to get better economy out of the Fuelsave stuff. I did have the car remapped when it was full of V-Power so not sure if the timings were adjusted taking that into account?

In terms of petrol the Shell V Power petrol and Tesco 99 were the best fuels you could get in the UK. BP had their version too but it may only be 98 RON - I haven't driven a petrol for years so I'm a bit out of touch with what is out there now, but again my old car had issues on anything below 98 RON but it was a Jap import.

On a standard normally aspirated car with no forced induction (i.e. no turbo or supercharger) I don't think it makes so much of a difference - just the better fuels with extra cleansers keep the internals in a better state. If you're not keeping the car for long it probably wouldn't make much difference tbh as the issues with shit fuel would raise their head after you've got rid.

This gives you an idea and was done by Pete at Thor Racing (I bought his other half's shopping car years ago which was about 350bhp :) )

https://www.youtube.com/watch?v=4boT3iwgZKI

I was under the impression that all the fuel comes from the same place and is delivered by the same tankers, there is talk of some places using additives in the petrol station tanks but who knows. I just use Esso now, on a long run I will use the higher octane stuff to blast the engine but it always seems like my mpg is worse on the higher octane fuels.

Used to know a morrisons tanker driver, all fuel is the same to begin with from the local refinery but it gets the additives added as the tanker fills. Different places have different 'blends' but always same fuel mix in the same tanker.

I remember running an old diesel (for years) on Rapeseed oil .. with a few litres of diesel just for the additives.. (stops it freezing / going sludgey in winter)
It used to be win win.. I would buy huge drums from Makro then all of a sudden cooking oil prices rocketed and if you now notice they are almost inline with petrol/diesel (most likely a government thing)

e.g. Cooking Oil in shops is about £1.50... used to be about 50p

The car did smell like a chip van but never had any problems, drove same and at time was about a quarter the price .......