Re: mechanical fan vs electric
[Re: Crizila]
#2247492
02/05/17 12:48 AM
02/05/17 12:48 AM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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For that post I was wearing my engineer hat instead of my doctor hat Since you seem to know Ohm's law, How long can his 650 CCA trunk mounted battery sustain a 25 amp draw with the engine off @ zero ambient temp before he can't start his car - causing him to miss his Doctors appointment? Zero degrees and he's overheating so badly he has to shut down but keep the fan going to cool the radiator? Sounds like the worst case scenario. At that point, I'd walk away from the car. No need to run the fan any longer than 90 seconds with the engine off to fully cool the radiator. I've tested this. From scalding hot radiator to cold to the touch. If the engine is overheating, that's the time to start it up, give it 2500 RPM to add amps back to the battery and circulate the water. If his battery can't supply power for 90 seconds with the engine off, again, he has other problems.
**Photobucket sucks**
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Re: mechanical fan vs electric
[Re: Crizila]
#2247584
02/05/17 05:03 AM
02/05/17 05:03 AM
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Joined: Oct 2007
Posts: 3,895 Oregon
hooziewhatsit
master
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master
Joined: Oct 2007
Posts: 3,895
Oregon
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Remember you will be putting an additional 25 - 30 amp draw on your electrical system - at idle, which could necessitate an alternator change. If you have to run the fan with the engine off because of an over heat, you got "other" cooling system problems that you sure don't want to deal with on the street. Some of the HP losses quoted with a mechanical fan are way on the high side (IMO) and usually don't take in to consideration the HP loss caused by the additional 25-30 amp draw that the alternator has to supply. Due to clearance issues with my street rod, I have to run a 16" electrical fan. Draws 24 amps and I can actually watch the rpm drop when it kicks on. Unless it has been damaged, Flex fans are as reliable as any metal fans. Mine sees 7K at the track all the time. That's what's nice about the mercedes fan. With the fan running at idle (25%), the ones I've tested pull less than 10A if I recall correctly. It might have even been around 5a Certainly nothing near the 30-40a it will draw at full speed.
If you ever find yourself in a fair fight, your tactics suck.
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Re: mechanical fan vs electric
[Re: mopar dave]
#2247676
02/05/17 12:54 PM
02/05/17 12:54 PM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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I have a serpentine pulley system. I had the electric pump and fan on last sb combo. They do have benefitts for sure. I already have the mech. Pump and fan. Just need the radiator at this point. Its good to get other ideas or opinions. Thanks I still contend that if you are running a large HP motor, mostly on the street, a large flex fan and good shroud are the way to go. It will move more air than most electric fans where you need it, Big improvement in street reliability ( no wires, relays, controllers, switches to contend with ), less than a quarter the cost, no additional burden on your existing electrical system. Trade off for the above will be a small amount of HP. Most cars today run electric fans. They were designed from the ground up to run them and only have to deal with cooling engines that are less than 1/2 the HP we are working with. "Yesterdays" cars only used mechanical fans - what they were designed for. IMO, it's really all about the application, as are many threads on this site. Both types have their +'s and -'s. Want reliability on the street, mechanical fan. Want that last bit of HP for the track, electrical.
Fastest 300
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Re: mechanical fan vs electric
[Re: ccdave]
#2247856
02/05/17 05:13 PM
02/05/17 05:13 PM
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Joined: Dec 2004
Posts: 10,555 Rittman Ohio
fourgearsavoy
I Live Here
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I Live Here
Joined: Dec 2004
Posts: 10,555
Rittman Ohio
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I'm running an old Direct Connection 5 blade clutch fan and stock repro pulleys from 440 Source on my 493 and it runs nice and cool at any speed. I'm running an older factory water pump that has less clearance to the Mancini housing. Later model pumps were designed with more clearance to run hotter for emissions purposes.(just a theory I share with a few other engine guys) Gus
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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Re: mechanical fan vs electric
[Re: Crizila]
#2248605
02/06/17 05:25 PM
02/06/17 05:25 PM
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Joined: Feb 2007
Posts: 5,080 organ
maximum entropy
master
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master
Joined: Feb 2007
Posts: 5,080
organ
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i run a flex-a-lite 19" 6 blade on my junk. i don't even have a shroud. my fan (and pump) are slightly overdriven (pulley size can make or break the combo). i have NEVER heard of, or seen, a flex-a-lite throw a blade. ever. their fans are rated at 8 to 10,000 rpm, depending on size. i tried every electric fan on the planet. wasted a lot of money, but learned a lot. the big dumb fan, and appropriate pulleys were the answer in my case. nothing fancy. the fan is quiet, and moves a preposterous amount of air. yeah, the electric freed up a couple of horsepower, but what good is that when you're stuck in a traffic jam, or hot lapping, and the temp is ratcheting upward? i'll gladly trade 10 hp for stonewall reliability. i actually won a race once because my competition couldn't make it to the line (it was a very hot day).
for what is the good life if not doing things thoughtfully?
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Re: mechanical fan vs electric
[Re: mopar dave]
#2248712
02/06/17 09:10 PM
02/06/17 09:10 PM
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Joined: Jul 2004
Posts: 4,384 Worst Weather USA
493_DART
master
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master
Joined: Jul 2004
Posts: 4,384
Worst Weather USA
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My setup never goes above 210 in the August heat..
A body , Rb , 12:1 , half filled , griffin alum rad. , 2007 HHR fan trimmed to fit , and stock water pump .
car trimmed to move the rad forward 1" .
I have around 1" from fan motor to w/p pulley .
Heres a link to the fan :
http://www.ebay.com/itm/Apdi-6016144-Engine-Cooling-Fan-Assembly-/361557605754?fits=Year%3A2007%7CModel%3AHHR&hash=item542e833d7a:m:mYc7ccvZDdaj_Sp_fQsp80Q&vxp=mtr
Last edited by 493_DART; 02/06/17 09:11 PM.
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Re: mechanical fan vs electric
[Re: maximum entropy]
#2248804
02/06/17 11:12 PM
02/06/17 11:12 PM
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Joined: Apr 2006
Posts: 4,220 West Plains, MO
DrCharles
master
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master
Joined: Apr 2006
Posts: 4,220
West Plains, MO
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yeah, the electric freed up a couple of horsepower, but what good is that when you're stuck in a traffic jam, or hot lapping, and the temp is ratcheting upward? i'll gladly trade 10 hp for stonewall reliability. The electric fan moves the same amount of air whether idling or high rpm. However, the mechanical fan is moving MUCH less air at idle, which is exactly when you need it the most. Fan clutches help by slipping at higher rpm but now there's another source of reliability problems. What kind of "hot lapping" are you referring to?Any time the car is moving over about 20 mph the fan only gets in the way. If you're overheating while moving, either the airflow through the core is insufficient, or you don't have enough radiator. The type of fan won't matter here. Finally, it's not "a couple" or even "10 hp", didn't you see the fan test article (and other similar tests)? Would you gladly give up 30 or 40 hp?
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