After my questions and good answers I have gotten here and elsewhere, I have decided to purchase a set of
Dual 11" fans. Have finally located them for what I think is a good price, $250.00. If anyone knows of a better
price, would appreciate the information.
My question is: How has the majority of the people have them wired, 1] to run constantly, 2] kicked on by
thermostat, 3] thermostat and air conditioner, 4] any other ways.
I realize that will have to run thru relay, also I want them to shut off when the engine is shut down.
All responses greatly appreciated.

Thanks

 

Check with Tom Dewitt, dewitts@ismi.net. He quoted me a price quite a bit better than that. To shut them off when the engine is off but the key is on, just run the wire that goes to the relay coil through an oil pressure switch. That is what I did with my fan (not a SPAL).

 

I paid 279.95 US at S&K Speed in N.Y. I have the fans, right now, wired off a coupla toggle switches. I can turn them on, key on or off. When I get some more time I will have one on thermostat and one either on a/c or live on toggle, all the time. I would still like to have one I can run with key off after a hard day in summer hot weather. Just a little extra cooling after shutoff.

 

That is a pretty good price. I bought all the parts for mine from BeCool.

Mine are wired with a relay and fuse for each fan. Since I don't have AC, both relays are controlled by the thermostatic switch (on at 195, off at 175). Since I didn't want to run the power cables to the battery, I got the 12V+ for the fans from the battery terminal on the starter. To control the relays, I wired them to a switched source under the dash. The fans will turn on when the car is running and hot, turn off when the car is off.

You definitely need relays since you are pulling 30+ amps through the dual fan setup. I peg my amp gauge when the fans are running off idle.
Here is the wiring diagram I used:


BTW: If you need to upgrade your alternator, try http://www.alternatorparts.com . I got the kit and went from 42 Amps to 80 Amps for $25 . They also have kits for 105 Amps.

 

Here is a pic of my install:


You can see the relays on the firewall between the wiper motor and the brake booster. The temp sensor is mounted in the thermostat housing because I could not get the plug out of the passenger side head.

I see no reason to run the fans after turning the motor off since the water pump is no longer circulating coolant. The fans will be cooling the radiator but the engine is dumping heat into the coolant in block which is not being circulated. If your fans are thermostat controlled (and the thermostat is in the head or engine where it should be) then the fans will run for a long time and drain the battery.

I ran my setup cross country (70+ mph, 100+ F temps, 2-3 hour legs) and the car never overheated on shutdown.


[Modified by SteveG75, 1:16 AM 11/7/2001]