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Old 11-09-2017, 01:42 PM
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AdamIsAdam AdamIsAdam is offline
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Join Date: Oct 2006
Location: Long Island, NY
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Quote:
Originally Posted by Schurkey View Post
Good, not great.

A shroud on the fan would make it far more efficient, which means you wouldn't need the "extreme-duty" fan clutch with a modified spring--or the horsepower to drive it.

The Heavy- and Severe-duty fan clutches are not suitable for use with typical automotive fans, (Less than 2 1/2" of pitch) because they'll never properly disengage. Hayden says as much on their web site.
http://www.haydenauto.com/Featured%2...s/Content.aspx

How much engine vacuum do you have at highway cruising speed?
Interesting reading...

As for vacuum at highway speed, I never got out to measure

As for fan shroud, I don't have a stock radiator, so putting a shroud on would be a project. So I figured I'd work in phases and stop when the results were acceptable. Since I never have temp issues at idle or low speeds, I was ok not having a shroud.

AND THEN I was watching an episode of Engine Masters where they tested various fans and shrouds. They found that a clutch fan robbed the least amount of HP over fixed, flex, etc. And then for kicks, they compared the clutch fan setup with and without a shroud and found that removing the shroud increased HP by 8HP. So I was convinced to go without.

https://youtu.be/ZXdLgaFXZzs?t=14m18s

As for the Severe duty issue, well, it works so I'll just leave well enough alone at this point. But good info, thanks!

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