Technical BP Ultimate (Diesel)

[mally]

I tried a tankful of this in my JTD and the results surprised me.
Here's my mpg figures over the last few months using either bog standard shell or sainsburys. diesel. The last figure of 42.91 is Ultimate. All figures are based on filling the tank to the brim and refuelling after c 400 miles. So - back to sainsburys or shell for me.
46.20
45.23
46.24
49.23
47.72
44.41
46.56
47.69
46.35
45.63
47.66
51.81
46.47
44.13
44.69
40.67
44.66
47.66
42.91

 

[Argonought]

47.66
42.91

You've got a low preceded by a high which often means you've filled from a different pump.

Did you go back to the same pump with car parked in same position etc

Same journeys?

Same air temp?

 

[PNL]

You've got a low preceded by a high which often means you've filled from a different pump.

Did you go back to the same pump with car parked in same position etc

Same journeys?

Same air temp?

And the same tyre pressures :chin:

I use sainsbury's ..one because its cheaper and two because its the nearest

 

[mally]

The very low figure was when I had a week off work and just pottering around. The high figure did involve one 200 mile round trip. The rest were my normal daily trips to work without much variation. All the garages are on level ground and my tyre pressures are kept at recommended. The BP ultimate figure of 42.91 was over the last 2 weeks which have been warmer than normal.

 

[LoBsTeR]

Diesel fuel ignites under compression and not with a spark. If a fuel ignites under less pressure, this can lead to pre ignition and can cause a 'pinking' effect. A fuel which is more volatile will ignite under less pressure thereby reducing the efficiecny of the combustion process. A more volatile fuel will give less power because it is igniting too early before the efficient TDC or Top Dead Centre of the piston. This has an effect of slowing the piston during its compression stroke and thereby reduces fuel efficiency. In theory, a fuel that is matched to the compression of the engine is ideal, but sadly, there are too many makes and types out there for us to put a finger on whats best. One mans meat is another mans poison.

It's really a case of trial and error. Just because you are paying more for a type of fuel (and perhaps getting a more explosive formula) does not neccessarily improve on performance and economy.

It's just a case of finding a fuel that your engine performs better with. With diesels, the more power you feel, the better the overall economy (provided that you drive with this in mind).

It could be that Peugeot/Ford/Vauxhall etc diesels love BP Ultimate. It's obvious your Stilo doesn't

I'll shut up now.

 

[JFL]

i need to go to tescos petrol station soon actually to make use of the 5p of a litre of fuel voucher i have, get a full tank, should save me a tiny bit