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Discussion Starter #1
I am deciding on what SPAL 16" fan to use on
my 67 Chevelle SS radiator for extra cooling.

I want to decide between a SPAL 16" push fan
that pushes out 1920 CFM and uses 17.5 amps
versus a SPAL 16" push fan that uses 2360 CFM
and uses 21.6 amps.

My question is whether the original amp on the 67 Chevelle SS can handle the 17 or 22 amps. I do not have any AC, power requirements, or stereo system.

Will I have to go with an upgraded alternator
putting out at least 100 amps ?

Also, is the difference between 17 and 22 amps negligable to debate ?

Thanks,

Ken McDee
 

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Assuming you still have the stock alternator, if I remember correctly its 37A, you should upgrade. You will rely on the fan during stop and go traffic, at idle a 37 amp alternator won’t keep up with the fan requirements. I would go with at least a 100 amp internal regulated, external regulated will work fine also. Replace the output wire, red #12 with a #8 connected to the horn relay. Get the fan power from the horn relay. I would use a 75A relay to control the fan and wire it with #10 wire.
 

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Discussion Starter #3
Mr. Colby:

Thanks. Are you saying replace the 135 Amp
alternator (I have one I previously bought for $50) with a # 8 size wire ? And, did you
say run the fan power to the horn relay ? I dont think you meant the alternator power.

I have purchased a Ron Francis wiring kit that includes a thermostat with 40A relay.
The fan will kick on at 200 degrees and turn off at 185 degrees. I am running a 180 thermostat.

Am I correct in the above ?

Thanks,
Ken McDee
 

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The alternator output was connected to the horn relay from the factory using a #10 wire. Actually the #10 wire from the alternator output has a soldered junction about 12” from the horn relay. From that junction there are three other #10 wires one connects to a fusible link and to the voltage regulator, one connects to the horn relay and the other connects to the junction block on the core support by the battery. I would disconnect the #10 wire from the alt. output, then install a #8 wire from the alt. output to the horn relay. You can get by without the larger wire but you will get less voltage drop and less heat along the length of the wire if and when the new alternator is cranking out high amps. Like when the headlights are on bright, the heater blower is running on high speed, the wipers are on, the new fan is on etc.

Yes use the 135 amp alt. you already have.

The wiring kit with 40 amp relay will work. I like the 75 amp relay (my mistake it is a 70 amp relay) like this for years of trouble free operation.
 
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