The reason I heard for putting the fan -behind- the radiator
is that only so much air can be -pushed- thru the radiator core before
it gets in it's own way and starts compressing between the radiator fins,
thus blocking the following air.
Putting the fan behind the radiator (in a shroud) pulls a vacuum on the
radiator core and allows maximum flow because it's -removing- air molecules
through it, allowing the following molecules plenty of room to jump right in.
:-)
ALWAYS use a shroud. This is what keeps the air from slipping off the ends
of the fan instead of going through it and the radiator. Whether you are
pushing OR pulling.
Not that there's room in a Spridget, but; on 'puller' fans a "plenum"
type shroud is a good idea because you can pull the vacuum on the entire
radiator surface instead of just the area of the fan.
With a 'pusher' fan the plenum would end up blocking off a large part of
the airflow, caused by the moving car, to the part of the radiator that's
not directly in line with the fan, and the fan would block part of that.
Ed in NC
Who said, "If nature abhors a vacuum, why did she create so much of it?"
;-)
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