Scott's Rams

["Joe Cantrell" <agiyo@domain.elided>]

Scott Fisher wrote, with excellent clarity:

The intake valve opens, the piston starts dropping, and air moves down
the intake tract.  Sometime later, the intake valve closes.  The air
which *used* to be moving down the intake tract now has to stop;
furthermore, air being elastic, it's going to bounce back out the intake
tract.  This "bounce" takes the shape of a wave of positive pressure
which reflects in the reverse direction to desired flow, moving at the
speed of sound for the local pressure and temperature.  When that
positive wave reaches an opening -- say, the inside of an airbox, or the
mouth of a carb -- it will dissipate into the air in the opening,
reaching pressure equilibrium....

Looking at one of the incredible Alfas at this weekend's Portland Historics,
I noticed a TZ-1 appears to have a reverse cone megaphone (big magic in the
'60's) on the intake tube leading into the carb air box.  Imagine how that
could be tuned!  I didn't get to see the motor of the TZ-2; wonder if they
were still doing it then?

The 8C-35 had mesh over the carb intakes' bell mouths, but that was 1935.
With 3.8 liters and twin Rootes superchargers, you could hear the air being
ripped up in those combustion chambers, and Peter Giddings drives it to make
Nuvolari proud.

What a weekend, kiddies.  We'll have pix on the AROO website sometime soon.
Joe

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