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Nice job and nice thread presentation.
And a little OT, I have always pondered the original concept of a fan shroud. Is it to move air by the engines fan thru the largest area of of the radiator by the fan, or is it to make the fan move the most amount of air thru improved efficiency by good shroud design (ie a simple tight fitting ring), albeit thru a smaller area of the radiator?
Seems to me the first goal would be best for low vehicle speed use, and the second more ideal for high speed use, since it would present less blockage of the radiator since most shrouds reduce airflow area at some point. However simply over sizing the radiator would, imo mask whatever results one observed to the above solutions
A shroud around the fan is mostly a low speed deal. It just optimizes the fan. At higher speeds with enough air hitting the front of the radiator the fan isn't so important. But that's where good shrouding in front of the radiator becomes inportant.
A guy that worked large automobile and industrial radiator manufacture explained to me the design of a fan shroud...
To get the optimum hole diameter for shroud take the fan diameter and add 10% of the fan diameter. So for my 16" fan I added 1.6" to 16" and cut my hole at 17.6".
The optimum depth of the shroud is when the pitch of the fan blades are showing 1/2 in and 1/2 out of the shroud.
Last edited by autoxcuda; 07/23/12 01:20 PM.
