Be Excellent To Each Other

Yay! This saved me lots of typing, thanks. I'm quite sick of being asked if I have a nectar card. No, I don't, and if you ask me tomorrow as well I'm going to start paying for everything in 5p coins. I don't care what the policy is, we both know I don't have one of your stupid cards.

The short version is that virtually always it's the same petrol. When I worked at Tesco we saw Texaco lorries as often as Tesco ones for example, franchises of Shell and the like just buy local petrol. The Tesco problems were confined to 1 single depot in Essex, which also supplied Morrisons in the area.

That said, I have 3 BPs right next to each other here near Hammersmith, and a Tesco near my parents in Amersham, once I get my car back I'll try both on the next two fill ups.

I vaguely recall from the internets around the fuel protests that all the petrol/fuel/whatever comes from something like two refineries.

The difference in the fuels comes when the companies add their own additive packages- the stuff that make Michael Schumachers tropical fish swim faster, or clean your engine etc.

It's like the companies trade/buy each other's fuel in different countries etc. I guess that saves a lot on transport costs.

I know it's supposed to be the same stuff and everything, but I remain convinced that there's "something" a bit different between Tesco and BP petrol.
We tried it with a Honda Insight recently. The Tesco fuel gets between 5 and 10MPG worse per tank. Repeatedly, over the same commute cycle.
Not that there's necessarily anything wrong with it, it just doesn't seem to let the car stay in lean-burn as well.

I would like to know what the difference is.

Mr Dave, what kind of car have you got?

Volvo 440. I'll ask my uncle (who used to work at BP) what the difference is. All he's said to me is that there was one when he worked there, but that they weren't really supposed to talk about it much.

As I said earlier, it's quite capable of consistently doing an extra london->Bristol length journey with Esso petrol over the sainsburys stuff. And I am not the only person I know who has found this.

But *why* would they bother doing this?

Beats me.

It's what they don't bother doing that makes the difference.

The theory here is that there are some additives that the expensive petrol stations add to their fuel that makes the car rum better that the supermarkets don't both with. I am extremely unconvinced, for the same reasons that I know all fuel pills and suchlike are scammy rubbish: there is basically not much you can put in petrol that does drastically effect how the car runs, certainly not on the "noticeable MPG higher" level that people claim to observe. Here is some interesting reading around this.

Perhaps it is actually rum rather than petrol.

I used to scoff at the idea that there was any practical difference myself, and I still think you'd be unlikely to notice it in a normal car. But as I say, it's repeatable and definitely a big enough difference to notice on the Honda above normal variation, looks like at least 6 or 7 %.

"The US consumes 20.8 million barrels of petroleum a day. A barrel of oil costs about $100 now I believe, go with that as it's a nice round number. In the US alone, a 5% improvement to fuel economy is a saving of $104mill PER DAY. If we assume the US uses, oh, 1/5th of all petrol then worldwide a 5% improvement in fuel economy is an approximate saving of $189.8 billion per year.

If you had the secret of magic things you could put in fuel that would improve fuel economy by 5% you'd be rich enough to hire Bill Gates to dress in a monkey suit and follow you around carrying your Nobel prize.

There are a lot of snake-oil products for fuel, but octane boosting additives, for example, are used and with measurable effect.

I don't think it's bizarre for the fuel companies to understand petrochemicals enough to add more ingredients to standard gasoline or whatever to make it work better. They already have different octane fuels besides.

Umm, what do you think fuel octane is? It has nothing to do with power output. Edumacation here.

Employ a person at every gas station to ensure everyone's tyres are inflated to the correct pressure. 5% improvement to fleet mileage.
Where do I get my prize now please thanks?

Seriously though, fuel economy is taken so un-seriously in the US, that pretty much any measure would have a dramatic effect. The point you are missing is that the oil and car industries and the government *DO NOT WANT* to reduce their oil consumption. It would not be a "saving" to them, so it is not in their interests to do it.


On the fuel difference thing, I'm not making it up, really. I didn't believe it, then I tested it, now I'm asking why there's apparently a measurable difference. Do Tesco heat their tanks or something?

edit:


So it's probably just that, right? Tesco gets a slightly lower blend from the refiners for a slightly lower price. Nothing to do with additives.

did I mention power? I don't think so.

Prevailing speed of traffic, traffic light cycles, air temperature, wind direction/speed - all vary slightly. As does the exact formulation of the petrol between batches - or possibly even the top and bottom of the underground tank, which will never be completely empty. Petrol does go off, so if it's been there for a long time it might be slightly less useful. A quieter station will probably have a dirtier tank too, so you might be getting more water/other contaminents in your tank too.

It might not vary so much that you'd notice day to day, but potentially enough to have a noticeable effect over the course of a tank of fuel.

You'd need a hub dyno running in a temperature and pressure controlled room and electronic control of the throttle to even get close to accurately measuring differences between fuel from two tankers.