Best "Sweet Spot" on a radiator?

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Curtishead

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I'm switching to electric fan(s) on my SBC. At this time, I have an 8 bladed 16" unit that is still awaiting the thermostatic relay and mounting brackets from LMC before I can mount it. I would really like to stay with one fan for now, and was wondering if anyone had definitive information on a "sweet spot" on the radiator's frontal(?) area to maximize the effects of the fan? The first asshole that asks me why I'm not sticking with the stock setup is barred from my account.
 

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Frankenchevy

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Please elucidate the benefits of eliminating the mechanical radiator fan assembly.

…see what I did there.

The design of the shroud and actual CFM of the fan are significant factors. Frontal area of the fan is less meaningful without other construction details of the radiator I.e. cores, thickness, material, etc.
 

bucket

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So many people here hate electric fans. Personally though, I like them. However, I very much prefer factory fans from a later model vehicle. Aftermarket fans are overrated.

With that said, the best place to put a single fan is anywhere within the core. There kinda needs to be a shroud though. And one that promotes flow through the core, not like some of the aftermarket ones that essentially make large areas of a radiator core a dead zone.
 

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The easiest way is to improvise.

This setup is quick, easy, and doesn't even require any wiring! - When you drive, the fan automatically spins by itself!

Except the guy in the picture put the fan in BACKWARDS! It's not going to work like that - it will blow the air the wrong way!
 

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legopnuematic

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What i dont like about the stock fan is how horror movie cut your finger off it is.

Other than that it works great haha.
You aren’t supposed to put yer fingers innit :Big Laugh:

I’d be more scared of a melon slicing flex fan over a stock clutch/fixed fan.
 

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There's no such thing as "sweet spot", you want as much of the radiator surface covered with a shroud as possible. If you can't put a good shroud on it, then it probably doesn't matter too much where you mount it, although I'd avoid the uppermost part of the radiator as that is more likely to be full of air if you run low on coolant and actually need the most cooling airflow. Putting it closer to the inlet gets the most heat transfer from the fan but the rest of the radiator doesn't have much driving force to transfer heat. Putting it closer to the outlet side lets the ambient airflow zap as much heat out of the hottest part of the radiator for the most "free cooling", but handicaps the heat transfer on the fan area. Altogether it probably doesn't make much difference without digging into the tiny details of how, when and where you drive it. So slap it on, try it out, and go from there.

I'm also not a fan of aftermarket electrics, I'd be a lot more inclined to use something off of a modern OEM setup or keep the clutch, the giant factory shroud makes the most of the radiator area. But to each his own, and make sure your power system is up to snuff for the entire thing, i.e. relays, wire, ground, and alternator all appropriately sized and working properly.
 

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