Rad fans on 165 on/off

[CSH-HQ]

If this is a street engine running a 190dF thermostat set fan on to like 
215, and off 195.
  If you want to use just a fan switch sender for a relay use the 87 GN rad 
fan switch, on 212dF off 200dF as I recall (and what I use for 747 
applications with elec fans).
  You "might" be over thinking this.  You can even consider that neither 
head is perfectly matched to the other in thermal characteristics, so the 
water at the thermostat is always cycling slightly from one head to the other.
Grumpy



>	>Just wondering how the ecm controled rad fan stuff works.  How can
>it know
>	>when to turn on the fan and when to turn it off? If the temp sensor
>is in
>	>the head?  Should it not be in the rad?  Ie, once the head reaches
>the turn
>	>on temp, is the motor not going to get hotter until the rad catches
>up?
>	>Then for turn off is the motor not going to have to reach like 170
>which it
>	>never will because of the thermostat.  How can you keep a
>consistant temp in
>	>the motor is you are not contoling the fans off of the rad temp
>(outlet
>	>specifically?)    I'm confused.
>	>Mike Rolica
>