Electic fans question

[jbristo67]

How are you guys wiring hour fans? Switch in the block or therm and relay?
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[bohmankid]

I run a relay and thermostat. You can buy them anywhere. I got one from Ebay and another from Summit. My thermostat is plugged directly into the radiator. I don't know if it matters where the thermostat is, but the fans turn on when it's hot and off when it's not, LOL. Works great. It's actually my second relay kit though because the first one kept fryin wires. Use big gage wires for big draw fans.

[jbristo67]

Jam going to try and do this pretty quick. Are our radiators big enough for 2 10 inch fans
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[piecesparts]

Originally Posted by jbristo67

Jam going to try and do this pretty quick. Are our radiators big enough for 2 10 inch fans
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I put a BeCool aluminum replacement radiator in my 84 truck, that is the same width as the stock one and I have a dual 11" SPAL fan set up that truck. I also put the same SPAL fans setup on my 91 Silverado with the factory radiator and they fit properly on that too.

[Rich84]

Taurus 2 speed fan...Only use the low right now. Fits nice covers about 80% of the radiator. Blows so hard it only runs for about 2 minutes at a time.

[SSC's76]

i run mine same as above. i have a electric thermostat in the radiator i got from advanced and a 30amp relay. i pieced mine togather about 30 bucks but you can buy the whole kit for 40. imperial makes the kits. i run a single 12 fan from a g body works ok does draw on the electrical system even getting juice directly from the battery

[jbristo67]

Do I need to upgrade my alternator
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[Ziegelsteinfaust]

You usually don"t need to upgrade the alternator.

Unless you plan to really work the truck hard below 20mph, have a giant stereo, and or a bunch of lights.

So if you answered yes to a 2 of those I would seriously consider a big alternator.

[rfmaster]

Originally Posted by Ziegelsteinfaust

You usually don"t need to upgrade the alternator.

Unless you plan to really work the truck hard below 20mph, have a giant stereo, and or a bunch of lights.

So if you answered yes to a 2 of those I would seriously consider a big alternator.

Please define 'usually don't' need to upgrade alternator? Most of the 70 and 80s trucks were equipped with 10/12 SI alternators rated at 62/94 AMPS.

The 10 SI can but out 23 AMP at idle (alternator shaft 1600 RPM)
http://www.acdelcotechconnect.com/html/tas_alt_10si.jsp

The 12 SI can deliver 32 AMP at idle (alternator shaft 1600 RPM)
http://www.acdelcotechconnect.com/html/tas_alt_12si.jsp

Taurus 3.8L single speed fans draw around 60Amp+ at start-up 30AMPs at steady state.

Mark VIII / Taurus Electric Fan amp draw - YouTube

To run serious cooling fans, such as Taurus fans (or similar) upgraded alternator is must. Stock CS-144 140Amp unit can deliver 80AMP (at alternator shaft 1600RPM) or CS130 105A unit can deliver 40AMP (at alternator shaft 1600RPM). Most of the times fans come on when you are stuck in traffic and under 20 MPH due to limited airflow through the radiator.

CS144 has slightly larger case than 10/12 SI units and requires mounting bracket modifications (ribbed belt or dual V belt setup is needed if large electrical loads are expected). CS130 case is similar to earlier 10/12 SI units. The CS series alternators also have better low RPM current capability vs. earlier 10/12 SI designs. Swapping to CS requires minor wiring changes to include L terminal wire series resistor. Details related to CS alternator swap have been covered previously.

//RF