Tuning for High Altitude Performance

[Mark Rosenkrantz]

I think this whole thing is purely academic.... however, from recollection,
the CIS will lift less with less density, meaning less fuel... so that's all
good.

But the base setting would be slightly off at high altitude (8000 ft.).  My
recollection of the metering head is that the arm itself is calibrated for a
specific density.... i.e. rate of change is only accurate at one density.
Of course, it's probably all academic.

Mark Rosenkrantz

On Thu, Nov 12, 2009 at 9:58 PM, Brett Dikeman <brett.dikeman at gmail.com>wrote:

> On Thu, Nov 12, 2009 at 9:51 PM, Mark Rosenkrantz
> <speedracer.mark at gmail.com> wrote:
> > Yes, it would.  I recall reading (years ago) about modifying (bending)
> the
> > arm for this purpose... but I'd have to find that book on the shelf
> > (assuming that I'm recollecting correctly).
> >
> > But either way, the flap's "lift" would change with density.  "Force
> > density" if I recall the correct term from basic fluid dynamics.
>
> Of course the lift would change, as it should.  The question is: does
> it change appropriately?
>
> http://www.google.com/search?q=bosch+CIS+altitude
>
> ...seems to indicate that maybe not, and some variants of CIS had
> additional measures for altitude compensation?
>
> -B
>