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I recently changed my broken clutch fan to a flex fan in order to facilitate better cooling at idle and really hot days around town. I'm coming to realize it sounds like crap (way too much noise) and seems like it may be robbing me of horsepower. Is this true? If so how much? I'm thinking I should change it again....thinking electric this time. Anyone have anything bad to say about going electric? Any suggestions? Don't get me wrong...the fan works great and fixed what I was looking for, but had the noise and it seemed to have hurt my gas mileage. I lost about 5-6mpg on the highway since this change!


Thoughts.........?
 

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i recently had fan trouble as well. my fan clutch was shot and my fan was actually WOBBLING. not good. a bad fan clutch will lead to a bad water pump, as they run off of the same shaft. flex fans are CONSTANTLY spinning, this creates a lot of drag on the motor. the theory is that as the RPM's increase, the fan blades (depending on your type of flex fan) actually flatten out from air force, creating less drag. i dont think it really works... your best bet honestly is just to go back to your clutch fan. i know plenty of guys who have a ton of engine mods and beat on their cars who still have the stock cooling fan. if you need a new a fan clutch and are worried about performance, partsamerica.com has the heavy duty fan clutch (came stock in the police interceptor) for about $65-$70 bucks. since the clutch fan only kicks in at certain temperatures, it is much less of a drag on your horsepower than the flex fan. of course the electric fan means NO drag, but there are other problems that arise. if you have a stock (75amp) alternator, adding an electric fan could lead to charging problems. also their is COST. the electric fan really only frees up like 10 hp i think (someone should be able to correct that number :rolleyes: ) probably less. for 200 bucks, there are better investments you can make. in conclusion! i say go back to the stock clutch fan. i didnt even get the heavy duty clutch, and my motor runs ice cold. if you develop temp problems, try a different thermostat. good luck!
 

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I'll be the first to tell you to swtich to an electric fan. I noticed a great increase in power and the car warms up MUCH faster.

The electric fan makes it much easier to work on the car. Like systronic mentioned , you must upgrade your alternator to run an electric fan. The stock alternator is weak as it is, so get atleast a 95 amp (130amp + would be better).

IMO , that flex fan is junk.
 

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A popular electric fan lots of Mustang guys use is one from a 3.8 V6 Taurus.

You can run it with a 100 amp alt.

I picked one up for under $50.

I used a Flex-A-Lite variable speed, soft start controller
which works like a dream.

You can set whatever temp you want to kick the fan on.
It starts it "slowly" so it doesn't have the big spike in
the amp draw when it kicks on, also delays it 5 seconds
when you turn the key on for the starter to avoid
double draw.

It varies fan speed based on how much warmer
the coolant temp is than the ON setting.

They have 2 diff controllers, you need the larger one
for the Taurus fan, works up to 40 amps. The Taurus
draws low 30's when running full speed.

The Taurus fan is easy to mount cuz it's not
"deep" like the bigger Lincoln Mark VIII fan,
yet still seems to pull plenty air.

You can see an installation if you go to the
Flex A Lite website, go to Automotive, then
Electric fans, then accessories.

Summit has the larger one for just under
$100 - it's worth every penney. Any electric
fan will increase you about 2 mpg highway
over a clutch fan, and the engine does warm up quicker.
 

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You can make do with junkyard fans if you are as poor and cheap as I am.:kooky:
I think you can snag the fan and the alternator off of one of those Taurus's - upgrade it all in one fell swoop. You can also cut the pertinent connectors and harnesses out of said Taurus.
I know someone who knew someone who was killed by a flex fan blade, (they like to come apart) he was just standing over his engine with the hood up...
 

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I recently installed a perma cool flex fan in my 91 GT. I can't really tell you how much of a difference it made because when I took it for a test drive(only got to drive it once), it started to rain so I took it back home and parked it and let it idle for a minute(I installed a new water pump, aswell.) I was checking for leaks, popped the hood and my radiator outlet was busted and coolant was spraying everywhere. So I really can't tell you how much difference it made. Anyhow, as for you guys saying a flex ran robs power.. yeah it spins constantly, but so did my stock fan with the fan clutch(I believe I have a thermostat problem). Not to mention the flex fan weighs FAR less than the stock fan. The flex is kinda of noisy but it doesn't bother me as long as it does its job. Right now there is a C4 in the car that's going out, I'm saving up for a T5 swap I believe.. better gas mileage with the OD, and 5spds are just... FUN! I'll baby the T5 until I have enough cash saved for a TKO 600.

*edit* oh and I would have went with an electric fan but money was an issue in my case, goodluck.
 

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A properly working/designed mechanical fan cools better from every article I've ever read. That is, someone wasn't trying to sell something.

At idle or low speed the electric has the advantage, but there is parasitic drag on the alternator to consider as well.

My opinions of course but I've not seen any scientific comparison, only opinion by thermal engineers..
 

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GhostDog 5.0 said:
I'll be the first to tell you to swtich to an electric fan. I noticed a great increase in power and the car warms up MUCH faster.

The electric fan makes it much easier to work on the car. Like systronic mentioned , you must upgrade your alternator to run an electric fan. The stock alternator is weak as it is, so get atleast a 95 amp (130amp + would be better).

IMO , that flex fan is junk.
I'll definitly have to back ghostdog up here. Its so much easer to work on your car with an electric fan. Save yourself the trouble and get the elec fan now. LEss drag on your belts too which equals easier crank turning so more power. I have a relay on my fan so it only turns on when the temp sensor tells it to. REward yourself and go with the electric fan. You won't be dissapointed.
 

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Don't know how accurate the info was, but I've read
that a mechanical fan can take up to 15 hp to spin
(I suppose locked up & at higher rpm)

The same article said a typical hi perf electric
fan only takes less than 5 hp to turn the alternator
for the fan load.
 

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i have a fan but i need a kit o install it (relay, wiring, switch) any one know of a place to get one?
 

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If you'd prefer a control that doesn't mess with relays,
the ON temp is adjustable, and it soft-starts the fan
to avoid the big amp spike, don't forget to take a look
at the Flex A Lite variable speed controller.

I really like mine.

Flex A Lite, Automotive, Electric Fans, Accessories
 

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Electric Fan is the way to go:

As soon as you are driving, air passing through the radiator is enough to cool the motor without the fan working. That's where you get the extra ponies.:cool: (almost zero loss for cooling as long as you are driving)

As mentionned above, soft start and alternator upgrade is not a bad thing to do.
 
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