Theo, Chris,
Some more thoughts from someone who has both an electric and mechanical fan.
My electric fan is operated by a dash switch - no thermostat. The advantage
of this is you can anticipate the need for extra cooling before a thermostat
would kick in. The problem with this is you (or at least I) sometimes forget
to turn it off once I'm moving again. Thus, a thermostat with a manual
switch override would be better I think. BTW, Theo, your idea to put a
toggle switch in parallel with the thermostat solves the failed open
scenario, but not the failed closed.
Chris, there are any number of Tigers that have done away with the
mechanical fan, but if you are going to rely totally on an electric one, it
better be good. I would recommend you look into using a dual fan setup, both
pushers, but arranged diagonally on the radiator so as to maximize the area
covered. Also, put the fans tight (or at least very close) to the radiator
so all the air goes through, not around. Get pusher type fans with small
diameter motors, not the pancake style used on puller fans. That way, you
won't be blocking ram air once you are under way.
Most, if not all, production vehicles with electric fans have thermostats
that are not switched at the ignition. You notice them sitting running in
the parking lot after the owner has long departed. If you think this is
"cool" and don't mind the draw on the battery, then wire it directly to the
battery (use a fuse of course). Otherwise, add a high current relay and
activate it from the switched power at the ignition switch, as per Theo's
instructions.
Bob
-----Original Message-----
From: owner-tigers@autox.team.net [mailto:owner-tigers@autox.team.net]On
Behalf Of Theo Smit
Sent: Sunday, March 11, 2001 1:10 PM
To: Mark Meswarb; tigers@autox.team.net
Subject: Re: Electric Fan Wiring
I'll make a correction to what I said (or at least, amend it)... As others
have
said, the thermoswitch may not like switching high currents for very long.
You can
reduce that problem by using the thermoswitch in the low-current circuit,
but you
end up running a little more wire around the car. I guess the other
advantage is
that it energizes the relay only when the fan turns on instead of
continuously.
If you're worried about the thermoswitch failing, then wire a toggle switch
in
parallel with the thermoswitch so that you can bypass it if necessary. Add
an
indicator lamp to the fan side of the relay to indicate when it's on. If you
put it
on the switch side, it doesn't tell you anything about the condition of the
relay...
Good luck,
Theo
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