Would it be worth it to try a flex fan or is it just a waste of money? I have a 3 row rad, a 180 therm, but I have the stock fan and my car is running a little hot in traffic. I was told that the electric fan is no good for street use. Also how can you tell if your stock fan is working properly? It is the original fan and my car is a 1990.
I don't trust flex fans as I have seen too many of them blow apart and cause SERIOUS damage. Electric fans work fine in traffic as long as you have a properly sized fan. Don't put one from a K-car on a blown 347 for example. If you are using the stock gauges to reference the temp in traffic remember that they are hopelessly inaccurate. Install a good Autometer (or something similar) gauge to get a true temp reading.
DONT USE A FLEX FAN.....
car craft did an article testing many different fans on a big block chevy(a 454 i think it was) and found that they LOST hp by using a flex fan instead of the fatocy clutch fan!!!
to test your fan, try spinning it when the engine is off. if it spins around freely about a full turn then you probably nedd a new one. but a new fan will cost you about 180 dollars from ford!! i know because i ve looked. i would go with an electric fan...there should be no reason why you cant use an electric fan on the street. the only thing is that they will draw more power from the alternator and if you have underdrive pullies it might cause some slight charging problems when standing still in traffic.
my suggestion is to go with the electric fan if you even need a new fan......check out the one thats on there first and see if it bad. if it is still good, you may need to try a different thermostat....sometimes even new ones will stick. so try this stuff out and see what you find!!
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1992 GT......
AOD to T-5 conversion, 3.73's, Zoom HD clutch, ported E7's, cut open and ported factory intake, ported stock throttle body, subframe connectors, 1.5" headers, o/r h-pipe, flowmaster cat back, MAC air tube, K&N conical filter, homemade heat sheild for filter, homemade cold air kit, MSD coil, 9mm plug wires, advanced base timing to 12 degrees, Chrome Pony rims, 235/55/r16 Cooper Cobras..... definately more to come!! ALL of this was done by myself....including the porting and gea
I had a flex fan, and my friend laughed at me and said i am losing so much horsepower cause they are huge, kill waterpumps, and are known to break...so it kinda made sense...car is running better with stock clutch fan back in.
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89' lx black hatchback
fms t-5z tranny,pro 5.0 shifter,king cobra clutch,underdrive pulleys,190lph fuel pump,equal length headers.3:73's,msd ignition coil, 65mm t-body,moroso cold air kit,2 1/4 2 chamber flowmasters,slotted rotors,fms aluminum driveshaft,auto-meter 5" tach, msd 6al - BIG oil burning problem! :(
best run 14.5 @ 101mph before some of the mods!
I would like to add my 2cents. I think you should get an electric fan you will see a big power increase. I have seen dyno tests that show a 40hp loss with a standard 5 blade clutch fan at 4500 rpm. It only takes about 1hp to run an alternator about the same for a high output version.
yeah, i saw a dyno test like that in car craft but it was on a big block chevy. they also did a test on a 5.0 mustang and only got 5 hp by switching to the electric fan. youll get more power but dont expect 40 hp.
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1992 GT......
AOD to T-5 conversion, 3.73's, Zoom HD clutch, ported E7's, cut open and ported factory intake, ported stock throttle body, subframe connectors, 1.5" headers, o/r h-pipe, flowmaster cat back, MAC air tube, K&N conical filter, homemade heat sheild for filter, homemade cold air kit, MSD coil, 9mm plug wires, advanced base timing to 12 degrees, Chrome Pony rims, 235/55/r16 Cooper Cobras..... definately more to come!! ALL of this was done by myself....including the porting and gea
i started a post to see if anyone had tried a electric fan in their mustang in the past. didnt get much response so i went out a baught a 2800 cfm fan for my car. car never ran so hot before in its life. i switched back to the stock fan setup and put a SMALL ELECTRIC FAN in front on the condensor to help push air throught the radiator whil the stock fan pulls. i have many mods to my car and even in traffic the car sits steadily at 185 degrees. and its been in the 90's over here in ny.
Flex fans don't draw any more HP than an electric fan.
Think about it,
First you have to convert hp through the belt to the alternator, convert that into electricity, run it through wires that loose resistance, then put it into a fan that doesn't get nearly 100 percent efficency.
Or just spin a razor blade off of your water pump.
Which do you think takes more power?
Believe me, I've had the dual electric fans on my blown 5.0 with a 130 amp alternator, with 4 gauge welding cable for a charge wire.
Ever see a belt smoke pieces of rubber off of the pulley? I have. I went through an incredible number of belts.
Along with the problem of finding a good temperature regulator for the electric fan control. I used to watch my temp go up, way up, then the fans would come on and it'd cool down to normal. Then do it all over again. Not too good for your cylinder heads. Especially aluminum!
But for your question, I'd say, You can't beat the stock "Thermal Fan Clutch". It only uses the amount of power that is required to keep the engine cool. That's the best bet for the street.
To test if it's bad:
Warm your engine up to operating temp or wait till it starts to over heat like you said, and then turn off the engine. Go to the fan and spin it by hand. If it spins over a whole revolution, it's junk. You need a new thermal fan clutch.
I just wanted to say that an alternator only takes 1hp or less to run and that is running everything your car has: lights, charging, ignition,electric fan or what have you. So I do not see how an electric fan can use more power.
Originally posted by 84GT I just wanted to say that an alternator only takes 1hp or less to run and that is running everything your car has: lights, charging, ignition,electric fan or what have you. So I do not see how an electric fan can use more power.
Uuuhhhhh huh, huh; Noooe
An alternator under decent load, meaning ignition, fuel pump, etc,, takes ~5 HP to spin. Now equate the fact that you have a nice electric fan to turn.
How much HP do you think it takes to make 130 amps?
Ever hear of an alternator kill switch? They're worth WAY more than one horse power.
Here do this, go to the dyno or the track. Run your car regular, then disconnect your alternator wires. Report back your time.
Energy isn't free. If it was, I'd have an electric blower. lol
I don't know I just saw some dyno results that show an high output alternator with a 90 amp load and it was only taking 0.8 horsepower to turn. Where do you get an alternator kill switch I have never heard of one?
I have a Black Diamond Electric fan on my Mustang, yea it cost a pretty penny but I have not had any problems with my motor running hot and I live in cetral Florida where its 90+ for 5-6 months straight. I do allot of stop and go driving with my A/C on with no problems.
I had a flex fan on a different car. I never lost any blades or parts but it just didnt keep the temp down with my 4 core radiator.
As for the Alt kill I cant speak for my Mustang but on my older muscle car I ran a jumper switch to the alternator plug so I could diable it from charging when going down the track. Made my car more consistant through out the night especially when it was dark and you had to have a tail light on. If it is diabled then the alt cant start charging half way down the track and throw off your times.
I have a flex-a-lite fan and haven't had any problems with it. Its funny when people stop you and say, "Hey buddy your car is still running." Then I just say, "Trust me, you will know when its running." Good times with the stang.
Flex Fan vs Electric Fan??? 
i started a post to see if anyone had tried a electric fan in their mustang in the past. didnt get much response so i went out a baught a 2800 cfm fan for my car. car never ran so hot before in its life. i switched back to the stock fan setup and put a SMALL ELECTRIC FAN in front on the condensor to help push air throught the radiator whil the stock fan pulls. i have many mods to my car and even in traffic the car sits steadily at 185 degrees. and its been in the 90's over here in ny.
Good times with the stang.
