Warm vs Cool Air

["Kim Boydell" <boydell@domain.elided>]

Here are some ramblings on hot vs. cool air discussion.  The engine
compartment is undoubtedly hot, but how hot is the air while driving at 50
Km, 100 Km, or 140 Km?  I assume that there is a lot of air flow through the
engine compartment but most of it goes through the radiator (I think but not
sure).  It might be interesting to look into this for someone who has access
to measuring instruments.

Second, does the air box have access to cooler air than conical
filters?  If so, then the solution is to put less restrictive filters in the
air box, or build a new air box around the filters.

There is another alternative.

My old Moto Guzzi motorcycle didn't have filters of any type on the twin
40mm delortos.  There were just a couple of velocity stacks with some
screening on the ends suitable for stopping small birds and big rocks.

I also remember being at a BMW service centre getting parts for my old 2002
and there were a couple of side draft dual-throated webbers waiting to be
pick up by someone who thought that faster wasn't fast enough (the love of
European, especially Italian motor vehicles of all types is a disease).
These had very long velocity stacks.

Now, is it possible to tune velocity stacks for different engine speeds?  I
assume that the intake stroke causes a pulse through the carburetor, so that
it may be possible to tune velocity stacks to take advantage of this pulse
by having a low pressure area inside the carburetor (or at the intake
valve?) causing outside air to rush in just as (a split second before?) the
intake value opens?  Or is it just the shape of the stack that facilitates
good breathing, i.e. the venturi effect?  Every velocity stack I have seen
is tulip or bell shaped.

Any ways, these are miscellaneous ramblings on the subject.

Kim

'79 Spider

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