[en1gma]

on the notes about engine breaking: on my automatic e39 530d, when in normal mode, whenever you take your foot off the throttle, the revs drops (like if you were 'freewheeling'/had the clutch in); in sports/manual mode, you get the engine braking.

In terms of driving style/mechanical sympathy, Jackie Stewart used to say (something like) 'brakes are for braking, engines are to make you move' - which I think translates to 'you shouldn't use/rely on engine breaking', as it's bad for the engine???

[NFS]

Originally Posted by en1gma

on the notes about engine breaking: on my automatic e39 530d, when in normal mode, whenever you take your foot off the throttle, the revs drops (like if you were 'freewheeling'/had the clutch in); in sports/manual mode, you get the engine braking.

In terms of driving style/mechanical sympathy, Jackie Stewart used to say (something like) 'brakes are for braking, engines are to make you move' - which I think translates to 'you shouldn't use/rely on engine breaking', as it's bad for the engine???

This is also the advice of the institute of advanced motoring and it's the way people are taught to drive now:

"brakes to slow and gears to go"

http://www.iam.org.uk/pressroom/driv...ivingtips3.htm

I still think this is bollocks, but what do I know

[agh!]

Diesel fuel - all the same at the refinery for any given batch, manufacturers use different additives, "better" additives make it an Ultimate / Excellium / Extra / Super whatever fuel. A BMW with OEM ECU map can be run safely on just about any non-biodiesel you can find in the world. To comply with EU emmissions regulations additives are used to boost cetane rating (a measure of combustion quality completely unrelated to Ocatane ratings for petrol) to a guaranteed minimum of 50, but due to variations in refining process inherent with diesel fuels it can often be higher and there are seasonal "winterisation" variations too.
BP Ultimate Diesel guaranteed minimum cetane 55 (any higher will not make any difference), Shell Diesel Extra as was now regular Shell Diesel 53, Total Excellium 53, other regular diesels 50/51. Variations in batches of fuel can create the illusion that regular Esso better / worse than regular Total etc. I always found Total much the same as Sainsbury's and Shell just a touch better than both of these. This was before I started experimenting with premium diesel fuels, Total Excellium to start with, but then the 11 December 2005 Hemel Hempsted fuel depot fire took that off the market in my area.
On average I measure 6% economy improvement with improved (October 2005 onwards) BP Ultimate Diesel from about the 3rd tank full onwards. I used to notice a small performance improvement and quieter smoother running, I don't seem to notice these differences anymore, only the fuel saving. I can measure improvements using Shell and Total Excellium (when it was available), not seen the new Shell V-Power Diesel yet.

In the context of 335d performance and fuel consumption, cars with and without re-maps, the differences between all these fuels is very small, but when you consider BP Ultimate Diesel costs about 6% more in most places and gives you 6% fuel consumption reduction you are breaking even on costs and getting those small performance / smoothness / quieter running improvements.
If you want to significantly improve performance, as said, squirt more fuel and air in.

[red355]

My experience over nearly 10,000 miles

I've tried BP std & ultimate.
Its runs smother on the ultimate blend but never seen a measurable advantage in MPG.

Tescos diesel surprising seems to have the edge on BP by about 0.5 mpg

But Total seems the best I have used...my record MPG is 44.3 using total

[mjh93sa]

The shell seems to be climbing in economy a bit now, so nothing to choose between any of the fuels used so far.

My record reading so far.....

[silverbmwz3]

Were you going round in circles with cruise control on matt ?

[mjh93sa]

That was a steady cruise up the Motorway to the 2nd UK meet. At about that point it was also suggesting a range of about 800miles! (BP Ultimate)

[tawia]

I put BPU in a remapped 2.0H.D.I once by mistake, i nearly shit at the difference in performance! Slightly better mpg too!

Im gonna fill my 320d up with it soon for a few tank fulls. See what i think. More interested in mpg return than performance.

i'll post after the first tank has gone...

[tawia]

Filled the car wit BPU diesel. So far not impressed! The car 'moans' something serious now when stopped but still in 'D' i have to shift it into 'N' for it to stop! Too early to say about mpg as i've only been 'in town' driving so far, also, does not feel as smooth as with standard diesel?

Does the car need to get used to the fuel?

Another thing i was thinking was that i live in small town, far from city size. Gets me thinking how long that BPU has been lying in the filling station tank for as with todays fuel prices i cant imagine many people using it! I may as next time im in how much they use compared to standard.

Going to try different BP station for next fill to see if its any better.

I'll be back to report more..