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Dual electric fans?


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Well it has been about a month since my original question and the water pump replacement. 

 

Short story:  Replacing the water pump fixed my problems.  No need to do anything else.  A properly functioning, stock cooling system cured my issues. 

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Everyone I know who plays in the desert has went back to the stock setup with a ZJ HD clutch. Dual and triple fans just could not move as much air as the stock setup.

I find that interesting since a mech Fan pulls very little CFM at idle, where an electric fan is pulling the same CFM at idle as at full RPM and a Good electric is pulling more CFM then a high RPM mech...

 

It really boils down (pun intended) to quality of the electric fan/fans used and the better the fan the higher the CFM...

 

I keep meaning to read the CFM flow across the rad with a mech fan @ idle and @ high RPM to get a proper # of Stock CFM used to cool the radiator and compare to the electric fan in same setup...

 

Glad its all fixed up for the OP..

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Well ill add my experience, i installed Hb's setup on my 91 2 dual 10 blade oem fans it worked great, until I hooked my lawn mower and trailer behind it within 10 miles overheating couldn't keep the heat down while towing anything during hot louisiana heat of summer, had to go back to the mechanical stock setup, hasn't got over 215 since, now saying that I very much preferred the dual electric setup especially for the noise factor, when the dam mech. Fan Locks up it sounds like a crop duster, but it does the job better than anything I've found.

 

Sent from my SAMSUNG-SM-G890A using Tapatalk

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  • 3 months later...

I am adding a 10 blade electrical fan to my MJ that currently runs JUST a 7 blade mechanical. Hey, the wiring is already there for the electrical so why not add one? Would it be worth my time to remove the mechanical and add dual electric by wiring each fan in series to the factory wiring? I'm not having cooling issues, but I would like more HP (even if its not noticeable, less engine load can't hurt).

 

I haven't quite found a straight answer on the G machine.

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By all means add the aux fan if  the wiring is there.

 

And yes, "less engine load can't hurt", but the load you save by ditching the mech fan will be negligible and you most likely won't notice it. And to do it right you should upgrade your alternator including it's wiring and the mains cables to safely handle the extra 20A-25A or so pulled by the second fan.

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By all means add the aux fan if  the wiring is there.

 

And yes, "less engine load can't hurt", but the load you save by ditching the mech fan will be negligible and you most likely won't notice it. And to do it right you should upgrade your alternator including it's wiring and the mains cables to safely handle the extra 20A-25A or so pulled by the second fan.

I saw that type of answer coming. I'll stick with a mech/elec combo then. Thanks for the help.

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Six month follow up report.

 

Not a single issue with the cooling system since getting the stock system running properly.  Even tested the truck on a 4100 ft climb in interstate 8. Temp goes up to about 210/215 and that is it.  

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The  price of the factory clutch fan is 7lbs of torque and 14hp. 

 

See dyno testing: Motor Trend On-Demand, Engine Masters, this months edition. 

 

Before anyone posts that the test was done on a V8 and is not relevant.........parasitic drag is going to be measured the same regardless of the engine or HP rating. 

 

7 and 14, that's the price, for those of us with 2.5s, we cannot afford the cost. 

 

 

I've been through many thermo switches, the one shown below works, cycles flawlessly.

 

Utyq8Tj.jpg

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The  price of the factory clutch fan is 7lbs of torque and 14hp. 

 

See dyno testing: Motor Trend On-Demand, Engine Masters, this months edition. 

 

Before anyone posts that the test was done on a V8 and is not relevant.........parasitic drag is going to be measured the same regardless of the engine or HP rating. 

 

7 and 14, that's the price, for those of us with 2.5s, we cannot afford the cost. 

 

 

 

This sounds right.  With the old Corvairs you could pick up 10-15 real horses by loosing the fan belt for a quarter mile run.  Made a difference!  But, that fan power goes up on a steep curve as the engine rpm goes up.  So at 70 mph on the highway and 2500 rpm, fan power is nowhere near 15 horsepower, that is a 5K rpm number.  

 

1 horsepower = 746 watts of electricity.  The battery has to be charged from the engine/alternator - so their is no net change in power over the long run.  Yes, the battery can store power for later use, so there is some time shifting of the engine power.  But over the long run, it has to be a wash (disregarding conversion losses).  This is why the clutch fan is popular, it trims the horsepower cost to run the fan at high speeds

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The  price of the factory clutch fan is 7lbs of torque and 14hp. 

 

See dyno testing: Motor Trend On-Demand, Engine Masters, this months edition. 

 

Before anyone posts that the test was done on a V8 and is not relevant.........parasitic drag is going to be measured the same regardless of the engine or HP rating. 

 

7 and 14, that's the price, for those of us with 2.5s, we cannot afford the cost. 

 

 

 

This sounds right.  With the old Corvairs you could pick up 10-15 real horses by loosing the fan belt for a quarter mile run.  Made a difference!  But, that fan power goes up on a steep curve as the engine rpm goes up.  So at 70 mph on the highway and 2500 rpm, fan power is nowhere near 15 horsepower, that is a 5K rpm number.  

 

1 horsepower = 746 watts of electricity.  The battery has to be charged from the engine/alternator - so their is no net change in power over the long run.  Yes, the battery can store power for later use, so there is some time shifting of the engine power.  But over the long run, it has to be a wash (disregarding conversion losses).  This is why the clutch fan is popular, it trims the horsepower cost to run the fan at high speeds

 

 

 

 

I'm not going to convince anyone of anything....not trying to.

 

Down the interstate/hwy at 70mph is not where you are looking for peak HP or torque. 

 

Fans don't run at 70mph............that is the point of an Efan..........they are not supposed to run. 

 

Cheap fans, poorly installed/wired, poor cooling systems...etc........has given the Efans  a bad rap. 

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