Electric fan cfm

[charger1972]

So I drove my car to work today for the first time sense it blew up last year . Broke a shifting rod on the way in , but that's a  different issue . On the way home got caught in a detour , stuck in traffic the temp got to 210-220 . The setup I have is a new one . Removed the mech fan for two 12 inch electric fans and a 4 core down flow aluminum radiator . The fans are supposed to be 1250 cfm a piece . Not enough I guess ? I did a search here and didn't really see a definite  answer for how much cfm is needed . Would a single 16 inch 3000 cfm be enough ? Thanks for any input .

[1974dodgecharger]

How much voltage u got going through em? I ask because u have 2 electric fans and maybe your alternator can not keep up and u will get a voltage drop thus decrease In performance of fans.

[charger1972]

They are wired through a relay , have a 100 amp tuff stuff alternator . The fans came with the champion radiator when i bought it , so decided to use them . But thinking maybe the 1250 cfm rating is a little generous .

[justcruisin]

IMHO it is hard to beat a clutch fan. There are electric fans and then there are electric fans. I gauge their value by the motor wattage not CFM ratings as I have found this to be misleading on some brands. IF you have a 4 core champion aluminium radiator it is likely  be 3" thick and on 3/8 spacing, it should cool well but being quite thick it will need some good air flow through it to disperse the heat. I use a three core 22" aluminium radiator with a clutch fan and I have an electric fan in front. The electric fan is on a thermo switch and is only there to keep temps below 190 on a hot day in stationary traffic - works well but I don't put my whole trust in a electric fan on its own.

[Cooter]

Remove electric junk and reinstall clutch fan 7 blade with factory shroud. Problem solved.

[bill440rt]

Do you have the electric fans due to a clearance issue with the 4-core radiator?

[1974dodgecharger]

Do you have the electric fans due to a clearance issue with the 4-core radiator?

I think it came with it i know mine did two fans i think same cfm also...my has a pusher fan.  Being 4 core those pullers won't be able to pull hard enough due to rad thickness, i would say.  


Yes like cooter saids u wont beat mechanical fan setup with clutch those pull like 4k cfm in general.  

I'm fine in az heat, with 3 fans but my electrical is up to snuff also.

As for your tuff alternator what spec say at idle, never go off max amp output its crap.  If u have two fans lets say thats 30amps taken up already and u need 30 alone to run the car so 60amps right there then add in other stuff if u have in it.

[bill440rt]

IIRC a puller fan (engine side) will be more effective than a pusher fan (grille side).
I do agree, a clutch fan is the best choice, however sometimes there are space limitations so there is no other choice.
Rad design may also play a factor.
Due to space limitations, I went with this puller fan:
http://www.summitracing.com/parts/FLX-410/

Says it puts out 2500cfm. My radiator is aluminum as well, but it has 2 larger tubes vs 4 smaller ones. This may also aid in cooling effectiveness.

[John_Kunkel]

Oh yeah, mechanical fans are so great they're still around.....not. 

[firefighter3931]

A crossflow rad is more efficient than a downflow and two large 1in diameter tubes are better than four smaller tubes.

Now if it stays cool out on the highway but heats up in traffic....that is telling us it's not a cooling capacity problem but rather an airflow problem....especially at lower speeds.

Mine has an Afco two row crossflow with 1in tubes and an 18in 3200 cfm fan set up as a pusher o the front of the rad. Thermostatic switch kicks the fan on at 175* and it will stay right there in traffic.


Ron

[flyinlow]

I have two 14 " electric pullers, no engine fan on a double core alum. rad. Each fan is rated at 2900 cfm .  Stays cool. Disconnected one accidentally and it starts to creep up to about 220* on a 95* day in traffic jam.

[Cooter]

Oh yeah, mechanical fans are so great they're still around.....not. 

Neither is a 2dr Charger....but I still drive one cause it works.

[charger1972]

I don't have any clearance problems , but they came with the radiator so I wired them up and fabricated a bracket to hold them . There is no shroud but they are mounted close to the radiator and would think they act like a shroud the way they are designed . I know the mechanical fan would be the easy way to go , but sense I already did the wiring , was going to try another type of fan . Someone told me the fan off a chevy hhr is pretty popular swap right now , and remember the Mercedes setup being popular as well . I`m going to the Syracuse nationals tomorrow , maybe I will see something in the swap-meet . Thanks for all the input always very helpful .

[John_Kunkel]

Oh yeah, mechanical fans are so great they're still around.....not. 

Neither is a 2dr Charger....but I still drive one cause it works.

Yeah, some folks still cook on a wood stove, get their TV from a rooftop antenna and their internet from a 56K  modem. After all, it works.

Others appreciate the difference between "works" and "works better".

[Musicman]

Don't forget about coolant circulation... many mechanical water pumps don't move a lot of water idling in traffic, at least not at a very low rpm. If your pumps not circulating a sufficient amount of water through the block, you wont be able to remove and dissipate the heat faster than it's being produced. There is an entire post here where we tested the output of a number of different pumps for this very reason. Proper coolant circulation is a critical factor in heat dissipation at low rpm.

[charger1972]

So , turns out one fan wasn't working at all . I picked up a 16 inch 3000 cfm fan in Syracuse , fabed up a shroud with the 16 inch and a 12 inch . Didn't get to drive it today to test it out , but will let you guys know how it works . Thanks  .

[bill440rt]

So instead of 2500 cfm you were only operating on 1250 cfm? Yep, that explains alot.
You should notice a big difference then.

Why was only one fan working? Were they wired wrong? Defective?
Is it still under their warranty?

[charger1972]

Defective . When I removed them , the one wouldn't spin free . Hooked to battery and wouldn't spin at all .

[1974dodgecharger]

Defective . When I removed them , the one wouldn't spin free . Hooked to battery and wouldn't spin at all .

you should be fine like I said I run 2 12inchers and one 16incher in AZ heat 110 to 115 if I can cool mine then you should be able to cool yours.

[charger1972]

Defective . When I removed them , the one wouldn't spin free . Hooked to battery and wouldn't spin at all .

you should be fine like I said I run 2 12inchers and one 16incher in AZ heat 110 to 115 if I can cool mine then you should be able to cool yours.

Yeah , haven't driven it yet . But I`m pretty sure it should be good to go .

[firefighter3931]

So , turns out one fan wasn't working at all . I picked up a 16 inch 3000 cfm fan in Syracuse , fabed up a shroud with the 16 inch and a 12 inch . Didn't get to drive it today to test it out , but will let you guys know how it works . Thanks  .

Sheesh....only one fan pulling 1250 cfm was working ? 

That sure explains a lot 


Ron