Will I need an upgraded alternator to run this Electric fan?

Any electric fan is going to overload a 65 amp alternator. The fan will draw 20-30 amps constant current and spikes up to 100 amps on a cold start.

Figure this:
Ignition system & computer = 12 amps
Fuel pump = 12 amps
Exterior lights = 15 amps
Fan (heater or A/C) = 15 amps (can run between 5-25 amps depending on setting)
Radio & instruments = 10 amps
Wipers = 10 amps
That's grand total of 74 amps from a 65 amp alternator. Talk about overdrawn at the bank!

The 3G alternator installation tech note is at http://forums.stangnet.com/showthread.php?t=646825
Make a a trip to the junkyard and get a MK VIII fan along with an alternator from a 94-95 Mustang. The 94-95 Mustang alternator is 130 amps and will run you $20-$60, the fan maybe a little more.


The best fan controller available today is a DC Control unit. www.dccontrol.com. Cost is about $110. Be prepared to wait 4 weeks or more to receive your controller once you have sent in your payment. The controllers are custom made in small lots and lead times can stretch out.

Next best is a SPAL controller - $70-$90 See http://www.spalusa.com/fans/automated/accessories/fanpwm.html. Ebay will have the controllers for the $70: do a google search and see what you find.

At the bottom are the Hayden or Imperial controllers available through Advance Discount Auto Parts and AutoZone. The non adjustable one is about $30 ( Hayden 226206) and the adjustable one is about $60 (Hayden 226204). I recommend you do a google search on Hayden and the part number for more info.

If you are good with electrical stuff (90% of the people here aren't), build your own controller.



If you are an experienced electronics tech or electrical engineer, email me and it will send you the prototype drawings of a fan controller that is probably as good as the DC Control unit. It is a build it, troubleshoot it yourself item. I will not build or troubleshoot units, so it is not suitable for anyone who isn't really good with electronics.

Alternate placement for a temp gauge sender or temp switch/temp sensor for an electric fan. Use the heater feed that comes off the intake manifold. Cut the rubber hose that connects the manifold water feed to the heater and splice in a tee adapter for the temp gauge sender. Be sure to use the same water feed line as the ECT sensor. That way you will get the most accurate temp readings.

Tee adapter info:
Make a pilgrimage to your local hardware or home supply center and get some copper pipe and a tee that fits the temp gauge sender. Solder two pieces of copper pipe onto a copper pipe tee with threads in the tee part. Find the correct brass fitting to match the temp sender threads to the tee fitting.

i have a mean E-fan on a stock alt and it works fine. I have measured how much it draws and it spikes to 85amps upon the intial spin and settles into a 38a draw. The only time i really notice how bad the alternator is is below 1000rpm backing out or starting in 1st w/ a/c going, music blasting, and headlights on. Then i see some dimming in my headlights and volt gauge is crying and pointing towards the bottom. Not to take away from the fact that any fox absolutely NEEDS a 3G/6G/etc, im just saying it CAN work.

There are a handful of guys whom post on the other forum that are in or near Columbus and part cars. You might score an E-fan or cheapo used clutch from one of them for a reasonable rate.

BHM, how in the world do you withstand a continuous draw of 38 amps (that's a ton!) on a stock alt? I guess your battery test passes. My hat's off to you for enduring the ebbs and flows on the system.

i have no idea when it clicks on theres a noticeable drop on the volt meter but then it jumps right back to where it was. I think the fact that i have high idle issues actually helps me in bumper to bumper as i idle at like a 1000 so it spins the alty a little bit more. I think if idled where i am supposed to (like 800) id start seeing problems.

get a 100 amp gm 1 wire alternator and change the pulley

Change the alternator dude. And trust me, even if you don't, once you get that fan on you will realize what I'm talking about.


If you want my 2 cents, I'm not with the Efan crowd, I've had some BAD experiences with Efans and I DO NOT recommend them. But if you can make it work so be it. My buddy has one that works well. We did the same change to mine and it wouldn't work.