On 22/08/15 10:35, Huge wrote:
On 2015-08-21, therustyone wrote:


The only time I've noticed a slightly smoother engine (though no
significant improvement in mpg) was when I accidently filled up
with premium diesel instead of standard diesel - and a lot of
that may have been wishful thinking to compensate for paying
through the nose for the "gold plated" fuel :-) I wouldn't have
minded quite so much but I'd driven past loads of garages on my
journey, holding out for the cheapest garage that I happened to
pass, and then when I found a cheap garage I went and used the
premium holster instead of the standard one. Shame they aren't
different colours (eg black versus black with yellow stripes, or
something like that).

might depend on the car's sophistication. A quality engine will
monitor pinking and adjust the timing

Diesels don't pink and have no ignition timing.

Wrong on both counts. Why am I not surprised?

Diesel 'clatter' IS pinking.. today's direct injection diesels vary the
timing as part of the fuel mapping - when you inject is largely when it
fires. And multiple injects per cycle can be done - that really helps
with the low speed 'clatter'

http://papers.sae.org/2008-01-1329/

I also have severe doubts that premium diesel achieves anything
whatsoever other than increasing the profits of the oil companies.


That's as may be, but there are definite issues with using some grades
of diesel in some diesel engines.

In particular biodiesel can lead to gumming of injectors and corrosion
of seals and fuel pump and injector parts, and diesel that doesn't have
additives may fail to absorb water and leave that at the bottom of the
tank, or freeze up badly in winter.

'City Diesel' was designed for vehicles that do stop start type motoring
and also IIRC features very low sulphur levels.

Marketing bollox is not all lies. Usually there is a grain of truth at
the bottom.






--
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