I've seen it mentioned on here before about needing a tankful or so to adapt, but have also read here that it's more or less instant. I can't see why they'd bother trying to adapt to a difference in fuel if it takes a tankful.

It'll be a while before I see any difference as I have only done 3 mile trips since filling up and the engine hasn't even got warm by then.

I admire your determination guys at adding various stuff into tank on a regular basis etc, I used to make a 80% veg oil / 20% isopropanol mix and add about 1l-2l per tank to the 1.9 Octy to quiet down the injectors (and it did improve low end operation somewhat, due to higher injection pressure).

But nowadays, I just fill up the cheapest fuel in the area that's coming from a large chain of supermarkets/oil companies/petrol stations (large companies only in case I need to go back and claim). I miss 100% biodiesel fill-ups though, they cleaned the engine nicely every year, but it seems all stations I used to visit, stopped selling B100.

The only thing I still do add to the tank (once or twice a year) is 99%pure isopropanol, about a pint per full tank, and that's only if I leave the car in the car park in mainland Europe in winter for over a week, and it's below -10degC. Stops me worrying about water content and wax in fuel, though the car would probably be just fine without it.

Lately I have been using Asda in the UK, Carrefour in France, Tango in Netherlands, Shell in Germany, BP in other countries. The last 2 because they happen to be convieniently located for where I want to stop. Saves a considerable amount of money compared to motorway services. E.g. on West-East autobahn A10, the diesel price difference Total Michendorf vs Shell Ludwigsfelde is 6 cent per litre, no queues at Ludwigshof, compared to 100% busy Michendorf, even at 4am. In France the difference between supermarket and services can be 15-20 cents/litre easily. £10 in your pocket every time you fill up, and usually also 5min-10min time saved, just by stopping in a different place along the route.

116k injector and pump trouble free miles say fuel quality is good enough, especially that I tend to burn it at 20l-26l/hr for half of the mileage. That is the beauty of the old 2.5TDI IP engine, it really is not that pickish about fuel (compared to PDs and especially CR), and will take just about anything that does not have much water and/or sulphuric acid in it (from bleaching agro fuel ).

Edited 28 February, 201313 yr by dieselV6

CR engines are like women... impossible to please hehe

I have made home made B100 and run my v6 on it, I swear it ran better on the pump diesel afterwards as methyl esthers are very powerful detergents. It was equally happy on neat bio. Need to make some more when the weather warms up. Carrefour all the way I say in France. In Germany/Austria I usually come off the bahn and full up in nearby villages as the savings are astronomical up to 20 cents a litre. That more than pays for my Vignette. I agree the vp44 is mechanically very tolerant.

Edited 28 February, 201313 yr by oh_superb

I fill up with asda petrol all the time and other day I filled her up with Bp ultimate diesel. I have noticed that the engine runs a lot smoother and is a bit more quiet too. Not noticed more poke cause your probably on talking 2-3 bhp on a standard of engine