Gauge lore, anyone?

[Scott Fisher <sefisher@domain.elided>]

All right -- Simon Phillips and Chris Keen both mention weird
acceleration-related effects to their temp gauge needles.  I've noticed
it on BOTH my Alfas, the '67 GT Jr. and the '74 Spider.

In the case of the Spider, the needle swings hard right (that is, to the
hotter side of the gauge) in right-hand corners, and swings back in left
turns.  Scared the *hell* out of me at the ARA autocross, as I come
blasting around a fast right-hander, sneak a glance at my gauges and see
it up over 240.  Fortunately, this was the first part of an S-turn and
it snapped back on the left-hander.  I remembered, and proceeded to
ignore the gauge during my next runs (probably why I was able to take so
much time off between my first and my last runs).

My standing temperature in pre-grid never got up to 212, even though it
was over 100 that day and I was really hammering on the motor on course,
so we can rule out any actual temperature changes of the kind
indicated.  Therefore it must be a mechanical thing -- the needle itself
actually swinging, yes?

Likewise, I've noticed that my Spider's gas gauge, when I get below
about 1/3 of a tank, swings wildly -- low on braking, then back up on
acceleration.  The oil pressure gauge, on the other hand, doesn't
flicker no matter what G-loadings I apply -- seems to stay between about
60 and about 75 PSI (only 0, 57, and 114 are marked) depending on
temperature and, to some extent, RPM (hot idle drops to, oh, 20 or so,
just less than halfway from 0 to 57).

So... what's up with that?  I have the Jaeger gauges (the ones in the
Spider are from a later-model car, installed when the P.O. put in the
nice, unblemished late-model dash -- the typeface isn't *quite* right
but it's not worth ripping them out just yet), are they known for this? 
Do other gauges have dampers on the needles that the Jaegers don't?

Thanks,

- --Scott Fisher
  74 Spider
  67 GT Junior

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