Viscous or Fixed fan Questions

You need a fan for racing or you will overheat in the pits.

I have a puller fan on the backside of the radiator.  The radiator has a fan switch installed and turns the fan on at about 190 degrees.  I think it only runs in the pits.

Near the fan is a fuse block with a 30 amp fuse connected to the kill switch.  The 30 AMP fuse is connected to the fan, the fan is connected to the fan switch in radiator, the fan switch goes to ground.

My car did not originally come with an electric fan.  I image all the stuff that was taken out of the car, more than makes up for adding in the fan alternator wise.  Been fine for 15 races.  Only time we have overheated is when a connector disconnected from the fan switch while we were waiting to get on track.

You should be able to find a ton of fans at the junkyard.

for racing, viscous or electric fan is good way to go. the mechanical fans are too high of a draw.

a 15A 12V fan which would be very high power is 180Watt is 1/4HP, with alternator at 50% thats 1/2HP to run a giant electric fan. at that point, can just run it full time .

besides big trucks, regular cars designed to run with no fans while moving. the minimum moving speed depends on the manufacturer. My miata was 15mph minimum, my challanger is 40mph.

BMW used to always put Viscous in manuals and Automatics often had fixed fans.  The RPM variation meant you were accelerating and decelerating the fan particularly when downshifting so the viscous isn't fully locked up all the time particularly at speed and that means the viscous fan isn't robbing power unless its too hot.

But electric would be my go to, mostly because you get a lot of flexibility on how to control it.

You can be fancy like newer cars where there is a pulse width modulation coming from the computer but personally I think the two speed type temperature switches are the best option powering either a single two speed fan or dual fans from many of the FWD cars.

You can switch from radiator temp, or head temps, or oil temps.  You can also use an automatic transmission kickdown switch to bypass the fan's power at full throttle which is a nice touch in a race car because you can also "de-energize" other items as you see fit at full throttle with ease.  Let your imagination be the guide there but anything electric you don't think you need at full throttle can be de-energized by simply controlling it through the step down switch.  Or energized you could blast an airhorn whilst turning off your fan if you felt like it.

Our Integra has two factory fans (which we connected together) that are switched via the factory temp sender.  We also have an override switch that simply sends a ground to the factory fan relay to turn the fans on manually when so desired.

In regard to flex fans, one may hear a old story about them failing, it can happen but its rare, what is most common is being sliced or sent to the hospital if you slip into its path while the car is running, for this reason,you couldn't pay me to run a non factory flex,, factory flax fans hurt but don't slice like aftermarket

The rest of the info is accurate, all of it, have run all ways including no fan, you only need fans below 40mph, a clutch fan will rob half the power of a fixed fan and a electric is stupid easy to convert (and the way we do things after trying them all) go wander the junkyard for something suitable.  Bring a drill battery to test it and don't forget the connector off the donor car.