Huw wrote:

> The latest hi-tech zenith of efficiency is the Viscotronic fan. This has an
> engine management controlled variable speed viscous fan. It is an amazing
> piece of kit. I happen to have a bit of experience with an application where
> a diagnostic laptop can be linked to the vehicle and the speed of the fan
> can be infinitely varied within reason by means of mouse on slider. It so
> happens that I have two near identical vehicles except that one has a simple
> viscous coupled fan and the other having the latest viscotronic unit and the
> reduction of noise from the latter is very noticeable. With the same fan
> blades it is probable that this equates to a significant gaining of
> horsepower or reduction in fuel consumption.

Cool beans...

That is the exact bit of trivial detail that had me asking the question
in the first place. On my Z3, once the engine reaches full temperature,
the fan noise at normal engine rpm (above 3000 rpm) is annoying, even
though I'm tooling along at a high enough rate of speed so that the need
for the fan is negligible.

-Fred W

PS - I'm just back from 2 weeks R&R in northern Maine, in case anyone
missed me (or hoped I had dropped off the planet...)