I got a mechanical engineering friend of mine to ponder the fan
placement theories and this is what he came up with:
     My thoughts as an engineer who believes in technology:
     1.  Fans work on volumes of air and heat transfer is based on mass
of
     air (number of molecules).
     2.  A volume of air will contain more mass at a lower temperature.
     --> fan on front
     3.  A volume of air will contain more mass at a higher pressure.
-->
     fan on front
     4.  More room in engine compartment would be nice.  --> fan in
front
     5.  Front or back, you need a shroud because the path of least
     resistance (lowest pressure drop) is around the radiator, not
through
     it.
     My thought as the technophobe that I really am:
     Shrouding the front of the radiator means you're relying on the fan
to
     cool the engine.  I think you would get more air through the
radiator
     with the shroud on the back if the fan fails.
     Realistically:
     It probably wouldn't make enough difference to an old engine to
even
     matter.  Especially if the hole in the front of the shroud is big.
I
     recommend performing lots of on-the-road tests to determine if one
     configuration is better than the other.  :)
Anyway, conclusion:  Inconclusive
adrian
--
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J. Adrian Barnes
http://user.icx.net/~adrian/midget
http://www.ravineware.com
"When there was no meat, we ate
fowl.  When there was no fowl we
ate crawdads.  When there were no
crawdads we ate sand."
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