Two cooling fans (was: 165 question)

Ken Kelly kenkelly at lucent.com
Wed Aug 5 19:15:24 GMT 1998


The new camaro F body uses a variation of the two fan Theme.
When you reach the low temp fan limit the two fans are put
in series, so they both run at 1/2 the battery voltage
voltage, and speed. It makes them much quieter and more
effecient than running one on only a part of the radiator.
When the second temp limit is reached it uses relays to put
each fan accross the battery supply, so they both run at
high speed.

		Ken

Andrew W. Macfadyen wrote:
> 
> Some manufacturers use this system I know  the UK  Rover use it in the higher
> performance turbo and V6 models in the 800 range. If you want to take the
> electronic route  you could do it several ways using a temperature sensor  (such
> as  a thermistor or LM335 sensor) connected to a simple voltage comparator (you
> would also need some kind of timer bassed on 555 chip)   or  a better one chip
> solution in the form of the Analog Devices  TMP12FP chip  which is designed for
> use in Pentium PC and actually  measures airflow and temperature.
> 
> Andy MacFadyen
> 
> AL8001 at aol.com wrote:
> 
> > In a message someone wrote:
> >
> > >>Wanted to have two fans in pu that came on at
> > >>>different temps. Have some minor drivabilty problems in really hot weather
> > >>>- hope to have ecm do controlling of fans instead of wiring to have come
> > >>>with eng running.
> > >>>
> >
> > It dosn't have to that complicated (searching for a ecm output and table ).
> > Look in a auto parts catalog for a water temp switch used for a hot light.
> > Many have a small screw covered by paint or sealer. Most of the older Ford
> > sensors have a threaded stud with a flat on one side.
> >
> > Clean off the paint, then turn the screw two turns clockwise. Most engines
> > have extra pluged holes in the intake or cylinder heads. Connect the switch to
> > the relay for the second fan.  Run the engine and adjust the screw to the temp
> > you desire.
> >
> > Simple, easy and cheap.



More information about the Diy_efi mailing list