I'm sad enough to check what MPG my motors use, there does seem to be a slight vareation between brands but I think what I do with the vehicle that perticular tank full makes the most difference, meaning despite 2 years worth of records I don't have many identical sorts of readings.
How to kill high efficency, obveous, drive in a hilly area with passengers/load.
Anyway, I try and work things out in terms of pence per litre as its most relivent, good MPG on expencive fuel can then compete farely with cheep stuff.
Texico has given good MPG in the past, other times average, its expenive though so useally gives poor ppl.
BP, simular to Shell, but a bit more costly.
Esso, same as BP.
Shell, one of my favorates, goes well and is cheeper than most other top brands.
Sansburys, I like it, had some of my best figues from Sansburys.
Asda, tescos, morisons, all prittly simular, rather like shell! You don't get supermarkets owning refinerys so they must just buy from whoevers offering it at a good rate that week. Probubly a given brand surplying a certain region, they might just add their own adatives if they want. Maybe thios regional vareation I put down to hills is actully down to regional fuel surplys? You can't do much about it so its pointless thinking too hard about it!
Biodiesel - this is what I'm really interested in recording, the 2.25D seems to give poor MPG on biodisel, meaning at the price its sold at here it doesn't actully save me any money in the ppl figure! Especally if I have to drive across town to get it.
Basicly I use supermarkets or Shell if I get the choice as they are probubly the best prices you'll find in a given area, and thats what makes the most difference. Big MPG changes are affected by what you are carrying and where, I drive places because I want to go there and I carry what I need when I get there so I can't really affect that other than driving sensably.
Got tricked into putting shell V power diesel (didn't know it existed, I just used the black pump) in the syncro once but other than being 5p more expencive than normal stuff (why can't they call it just diesel or normal diesel? "Diesel extra" makes it hard to workout whats the normal stuff and whats the ripoff stuff) the van clearly wasn't bothered by what it was running off - MPG didn't change.
Interesting point about foaming, in the landy (filler under seat) I always watch the fuel going in and some brands do look more foamly and creamy, in the van on the otherhand sometimes it doesn't fill to the top of the guage despite being cut out on the pump and leavel - never thought this was related but maybe it is. I do find it anoying as the syncro is hard to get a consistant fill - its got a big tank and I haven't had it a year so not much fill ups recorded eather. The landy racks up the miles though so I know what that does, and fill it to a marker so its accurate.
