Upgrade mechanical fan vs installing electric fan

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Let me give you an example from fan charts. I f you have a fan that takes 5 hp @ 848 rpm to produce 2.5 in. static pressure, at 1383 rpm, a 63 % speed increase, it will take 21.7 hp , or a 334% increase in power to produce the same 2.5 in. static pressure. That, my friend, is an exponential increase in power.

Thats on a fixed pitch fan blade, correct?
Doesnt seem to account for the non clutch type fan blade flattening out substantially at rpm.
 
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Thats on a fixed pitch fan blade, correct?
Doesnt seem to account for the non clutch type fan blade flattening out substantially at rpm.
Yes. The numbers are for the same fan, not a different pitch. I agree that the blades would actually flex a bit and flatten their pitch a small amount at higher rpm, not substantially or you would see blades fatigue, break, and fly off frequently.
 
Ive always seen substantial flattening of the blades on the non clutch fan.
They are designed to flatten out as rpm increases.
 
The blades are pulling forward very hard at high rpm. Could you be seeing the blade tips move toward the radiator?
 
trailing edge flattens, more as rpm increase.
I'm sure its not a straight line HP curve but I'm not believing exponential with this particular type of fan.

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@Jimacuda While I’m not convinced of the “exponential” portion of power lose ether, I do believe to use the least power robbing unit possible. This is just basic hot rodding sense.

What I see in your picture is a fixed fan. A switch to a viscous coupling would be a good move. When it comes to the fan itself, the number one item is how well it moves air since that is the cooling function it is employed to do and it must do it. If you can get away with what ever style can you want to run, then your in good shape.

I just don’t know which (actual) fan moves the most air. I myself stuck with the MP viscous fan set up with the fan having 5 oddly placed blades.
 
thanks but the fixed fan is functioning beyond expectation, even without the shroud I fit to it installed.
sitting idling at 900-950 rpm in traffic for several minutes it stays under 190* with 105*+ ambient.
Running on the freeway at 75mph/4000 rpm its 185* or under with 105*+ ambient.
19" 7 blade Chrysler fan approx. 1" from rad.
Trans cooler is mounted in front of upper drivers side of rad.
Maybe 15% coolant mix at most.
Obviously not a stock rad...holds around a gallon more...and fills the core opening.
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trailing edge flattens, more as rpm increase.
I'm sure its not a straight line HP curve but I'm not believing exponential with this particular type of fan.

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I have never seen a stock factory fan flex, the one in the pic doesn`t look like any stock fan Ive ever seen. Looks like an aftermarket to me. Most Flex type fans are dangerous if u set total timing under the hood.
 
IMO either system is o.k., BUT, if you go electric you MUST upgrade your electric system . The alternator can't take the load . Either can the wiring . this can escalate into an expensive nightmare . Try the mechanical route first : High flow water pump & thermostat , clutch fan , oversized radiator , water wetter , etc. If that doesn't work , I think it will , go the electric route . BWT, electric fan(S) draw 30 amps & electric water pump draws about 30 amps. as well
 
I have never seen a stock factory fan flex, the one in the pic doesn`t look like any stock fan Ive ever seen. Looks like an aftermarket to me. Most Flex type fans are dangerous if u set total timing under the hood.

Dont know what to tell you but its stock mopar and I have a couple of them.

So, something new for ya Bob!:D

Yes, fiberglass flex fans are dangerous.
Spring steel bladed fan...not so much.
 
Dont know what to tell you but its stock mopar and I have a couple of them.

So, something new for ya Bob!:D

Yes, fiberglass flex fans are dangerous.
Spring steel bladed fan...not so much.

live and learn I guess !
 
the kit... i haven't seen either separate though..

I went the elec fan thing first, experimented w/ more things than I can remember, ended up with a mech. fixed set up, hi flow pump, and stat w/ water wetter, 28x19 crossflow rad. , shroud, even cleaned up the alum. pump housing . might still play w/ it more when hot weather returns.
part of my problem is fan diameter.
 
This went off into the weeds. I chased overheating issues for 2 years before i switched back to a manual fan; i did buy a "too think" Griffin though.
 
I run the factory 2 core 26 inch rad with a declutching fan from a 70 swinger 340. No fan shroud.Stays at 190. 470 stroker. 655 hp 622 tq. Block is half filled with hard block. 36* Celsius is as hot as it usually gets here. Only quarter mile runs though. It will idle for a long time without getting hot. Kim
 
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I run the factory 2 core 26 inch rad with a declutching fan from a 70 swinger 340. No fan shroud.Stays at 190. 470 stroker. 655 hp 622 tq. Block is half filled with hard block. 36* Celsius is as hot as it usually gets here. Only quarter mile runs though. It will idle for a long time without getting hot. Kim

One reason I have had heating problems in the past , is probly because of the 17" fan , I would have to relocate my 28x19 crossflow griffin and build another shroud to run a bigger fan. For the last of the summer I had it pretty well whipped w/ the mech. 17" fan tho-----still would like to run the clutch set up tho.
 
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