clutch fan
Mountain Pass
Joined: Mar 2002
Posts: 190
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clutch fan
If you mean a fan clutch, then its purpose is to pull air across the radiator and a/c condenser. The fan clutch locks down when air coming across it reaches a certain temperature and starts to pull more air. At lower temperatures it spins freely at a lower speed than the engine (by design of the locking mechanism) to reduce drag and horsepower loss.
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Senior User
Joined: Oct 2002
Posts: 379
Likes: 0
From: Shawnee , KS
clutch fan
hahaha good response steve thats straight to the point and in my language hahahaha. alright. i wonder if that puts extra stress on the engine resulting in lower gas mileage hmmmmm.
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
clutch fan
How could it put EXTRA stress on the engine? The clutch is normally DISengaged, until its thermostatic coil (visible on the front) warms up and turns the lock shaft. Then, it's no more a strain than an old solid fan.
Senior User
Joined: Mar 2002
Posts: 450
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From: Charter Oak, Iowa
clutch fan
You usually can hear and feel when the fan clutch locks up. The truck will roar and you'll feel the loss of power in comparison to when the clutch is disengaged. Alot of times when the fan clutch goes bad, it will simply lock up and the fan will spin just like a solid mounted fan. Gas mileage will definatley suffer then. Like 2-3 MPG. It's a good system when compared to a non-clutched fan. Some guys are adapting in electric fans and eliminating the fan and clutch system on the end of the water pump in hopes of power and economy improvements.
Randy
Randy
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Elder User
Joined: Sep 2002
Posts: 780
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From: US
clutch fan
I have a flex lite on my truck now till i feel good enough to put the electric ones back on. Its LOUD VERY LOUD. I got the 2" spacer with it but it still needs to be moved in another 1" I can notice the millage too. save up and buy the electric. Check out www.flex-a-lite.com
Lead Driver
Joined: Sep 2002
Posts: 9,576
Likes: 2,039
From: North Texas
clutch fan
I just purchased a 94+ Mustang GT cooling fan for $40 from Ebay (I love that place) with 12" of harness.
I will be taking my old flyswatter off hopefully in about two weeks and swap the electric in. I am using a Hayden adjustable thermostat w/ A/C relay.
Power gains are negligable usually around 5-10rwhp. But there will be no clutch locking up causing hard-core power loss and MPG loss in the summer. There will also be less parasitic drag on the accessories freeing up that power.
A single large fan usally draws about 20A. So with my 130A max alternator I'll be set, even with my underdrive pullies and my headlights on and A/C blowing. As long as I stay above 12v at idle all should be okay.
I will be taking my old flyswatter off hopefully in about two weeks and swap the electric in. I am using a Hayden adjustable thermostat w/ A/C relay.
Power gains are negligable usually around 5-10rwhp. But there will be no clutch locking up causing hard-core power loss and MPG loss in the summer. There will also be less parasitic drag on the accessories freeing up that power.
A single large fan usally draws about 20A. So with my 130A max alternator I'll be set, even with my underdrive pullies and my headlights on and A/C blowing. As long as I stay above 12v at idle all should be okay.
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
clutch fan
Using an electric fan only moves the parasitic drag to the alternator instead of the water pump pulley. The power to spin the fan has to come from somewhere, and in fact, it takes slightly MORE with electric because of the resistance in the wires and inefficiencies of the alt & fan motor.
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
clutch fan
But when the clutch is unlocked, it drops to almost nothing. And whe the vehicle is driving faster than the fan is trying to pull the air, there is NO drag on a mechanical fan, where an electric is STILL pulling electricity.
I'm not saying an electric has NO benefits; I'm just saying it's not free, and no better than a clutch for power consumption.
I'm not saying an electric has NO benefits; I'm just saying it's not free, and no better than a clutch for power consumption.
Mountain Pass
Joined: Mar 2002
Posts: 190
Likes: 0
clutch fan
The engine isn't going to have to work any harder with a 30A electrical pull if you have a sufficient alternator. Seems like to me the electric fan would ease the load of spinning even a clutched fan, which does require some effort even when it is not engaged.