Motor Driven and Electric Fan?

[jeepboy]

Hey, Im about to put a puller fan on my 74' CJ-5 but my Brother in law said I'll have to take off my motor driven fan because having both on there at the same time will be worthless. He said something about how one will be sucking the air in faster and it will create a "vortex" and it will actually hurt the cooling effeciency of the fans. It this true or just BS.

I have a 304 and it runs a tini bit hot (and yes I said tini). my motor driven fan is worthless but my theory is the more air moving around the engine the better. Does the majority of the cooling come from the air going through the radiator or the entire engine block itself?

I get confused when it comes to spiraling vortexs under the hood, i dont know that much about them because i havn't needed to relplace mine yet :rolleyes: :D

[Devil Man]

Hey, Im about to put a puller fan on my 74' CJ-5 but my Brother in law said I'll have to take off my motor driven fan because having both on there at the same time will be worthless. He said something about how one will be sucking the air in faster and it will create a "vortex" and it will actually hurt the cooling effeciency of the fans. It this true or just BS.

I have a 304 and it runs a tini bit hot (and yes I said tini). my motor driven fan is worthless but my theory is the more air moving around the engine the better. Does the majority of the cooling come from the air going through the radiator or the entire engine block itself?

I get confused when it comes to spiraling vortexs under the hood, i dont know that much about them because i havn't needed to relplace mine yet :rolleyes: :D
i run a pusher & a puller no motor driven fan & it works great:D

[Wildcat455]

Hey, Im about to put a puller fan on my 74' CJ-5 but my Brother in law said I'll have to take off my motor driven fan because having both on there at the same time will be worthless. He said something about how one will be sucking the air in faster and it will create a "vortex" and it will actually hurt the cooling effeciency of the fans. It this true or just BS.

I have a 304 and it runs a tini bit hot (and yes I said tini). my motor driven fan is worthless but my theory is the more air moving around the engine the better. Does the majority of the cooling come from the air going through the radiator or the entire engine block itself?

I get confused when it comes to spiraling vortexs under the hood, i dont know that much about them because i havn't needed to relplace mine yet :rolleyes: :D


Majority of cooling comes from air going thru the radiator.
Putting an electric fan in front of your mech fan as a puller, doesn't really make much sense, maybe that's what he's trying to tell you.

First, I'd recommend you look into all the variables that could make it run a little warm. I assume you know what they are, so I wont waste my time typing them. If you don't, just ask and I'd be happy to.

Is this a stock setup?
Why do you say your Mech fan is worthless?
When you say "Tini bit", what temp are we talking?
During what driving conditions? Slow, Fast, all the time?

[jeepboy]

Its an almost stock setup, its a 304 with a way low end torque Comp Cam, Headman hedders. The temp is at 200 all the time, it never goes over that. But I just put a temp gauge on it that actually shows the temp. Im just worried about the summers.

Right now after driving around town then opening the hood....:eek: , its like a punch in the face. You could roast mallos over the the air filter. The engine temp seems okay but the overall temp of everything around the engine is boiling. I kept getting vapor lock because my hedders were too close to the fuel line, and they also melted my speedo cable (not that it worked anyways :D ). I dont boil over anymore now that I went to a 16lb radiator cap but Im worrid about my brand spankin new engine (less than 1500 mile on it) dying off early.

And Ive heard that an electric fan increases Horse Power, not that I dont have enough already, but you cant have too much horse power :D

The fan i have now bends like a pretzel. It isnt still at all, and it only has 4 narrow fins on it.

[SavageSun4x4]

Hey, Im about to put a puller fan on my 74' CJ-5 but my Brother in law said I'll have to take off my motor driven fan because having both on there at the same time will be worthless. He said something about how one will be sucking the air in faster and it will create a "vortex" and it will actually hurt the cooling effeciency of the fans. It this true or just BS.

:D
He is mostly correct.

Perhaps you should look at a 7 blade motor fan if available for your rig.

[My1stJeep]

The electric fan by itself does not increase horsepower, by by a side affect it does. You lesson the drag on the engine by removing the mechanical fan, which opens up a few ponies, that is where the increase comes from.

Have you upgraded the radiator?

I think the electric fan will help on slow moving trails runs, stop and go traffic and such. Plus if it is hooked up to the temp, then it will run even when you stop the engine to keep air flow going around the engine area and help cool it off as it sits. This will be minimal cooling, but will help.

Not sure it that really helped answer your question.

[TomHatch]

This rather long post really only applies to heating problems at high speeds.

After 4+ years of summer-time problems with my 5.0 Mustang I called Performance Radiator to pick their brain. I had already upgraded the radiator, thermostat, fan, and water pump and couldn't think of anything else to waste money on. After listening to me for a few minutes he (my new best friend) asked "how are your air dams?" (The air dams are the plastic L shaped pieces under the front bumper that force air up in front of the radiator. The faster you go the more air it will force up.) My mind went back to the day I bought the car when I was looking under the front end and saw that the air dam was hanging by a thread. I pulled it off and drove the car home. I sheepishly replied that I didn't have an air dam. Performance Radiator sent me to Ford Parts to get my air dams. After putting my air dams on I checked my coolant temps and ambient air temps (I have an autometer gage that reads engine compartment ambient air temps.) Just adding the air dams dropped my ambient air temp by 30 degrees.

To make a long story short... If you want to drop your ambient air temperature in the engine bay fab an L shaped scoop to force air up in front of the radiator (or just buy the plastic one for a 95+ Mustang and install it). I am not sure how much an air dam will help a Jeep because our nose, being already tall and flat (non aerodynamic), already catches lots of air; but it wouldn't cost much to find out.

[Wildcat455]

Its an almost stock setup, its a 304 with a way low end torque Comp Cam, Headman hedders. The temp is at 200 all the time, it never goes over that. But I just put a temp gauge on it that actually shows the temp. Im just worried about the summers.

Right now after driving around town then opening the hood....:eek: , its like a punch in the face. You could roast mallos over the the air filter. The engine temp seems okay but the overall temp of everything around the engine is boiling. I kept getting vapor lock because my hedders were too close to the fuel line, and they also melted my speedo cable (not that it worked anyways :D ). I dont boil over anymore now that I went to a 16lb radiator cap but Im worrid about my brand spankin new engine (less than 1500 mile on it) dying off early.

And Ive heard that an electric fan increases Horse Power, not that I dont have enough already, but you cant have too much horse power :D

The fan i have now bends like a pretzel. It isnt still at all, and it only has 4 narrow fins on it.

Ok, sounds like a flex fan.
If you have a fan shroud, measure the opening, and put a fixed blade mechanical fan on it that will fit inside the opening.
If you don't have a fan shroud, put one on then proceed as above.

The relationship between the fan, the shroud and the proximity of the fan to the radiator is pretty important.

As far as HP loss, your probably only talking like 7-10 HP, and the electric fan probably wont cool your motor like the mechanical will.