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Keep E-fan running after shutdown?

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Old 07-18-05, 06:09 PM
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Keep E-fan running after shutdown?

Would anyone know how you could wire your e-fan to run for a set amount of time everytime after you shutdown your car. I would like to try and do this because I will in AZ where it is hot most of the time this way, it would keep my eninge cooler after shutdown. I have notice there are a lot of factory cars have a device like this. I have a turbotimer, but I would still like to run the e-fan just a little longer with the engine shut down.

I was wondering if I could make something from parts I could buy from radioshack or if there is a relay made for another vehicle with this built in?
Old 07-18-05, 06:30 PM
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i dont know how much that would help b/c when the engine is off the coolant its circulating, unless your plan is tp keep the engine running at the same time, i'm sure theres a way you could wire it to work with the turbo timer, or at the same time length.
Old 07-18-05, 06:36 PM
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Wouldn't this help with heatsink or w/e its called. When your engine ends up getting hotter when the cars off?
Old 07-18-05, 07:27 PM
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yeah even if the engine isn't moving coolant it's still leeching the heat away.

Most of the time you can get away with just taking it easy for the last block before you shut it off.

Most temp switches for E-fans have a bypass switch which you can use.
A timer would just hook up to that. Not sure on how or where to get one though.

You could just set it with full time power instead of an ignition source and a Temperature switch. This means that it will stay running while the car is off until the temps drop down.

It may be a while out here but it still won't stay on forever and drain your battery that bad.

I'm debating whether I am going to use ignition or full 12v source for my efan setup.
Old 07-18-05, 07:38 PM
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I used the $19.99 rheostat temp switch from Autozone or Advanced Auto

I wired it directly to the battery. My fan will kick on and off as the temp exceeds 185. Being that it is fully adjustable, it means you can dial it in to any temp you want. Worked great with my Fiero E-fan from the local junkyard.
Old 07-18-05, 07:42 PM
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My fan has a $17 thermo switch from autozone going strong for 3 years when I shut the car of it still keeps cooling until it gets to the right temp it works perfect
Old 07-18-05, 07:54 PM
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I would consider doing that but in arizona during the summer when it gets to 118 degress ambient, I would be afraid the fan might have to run for a lonnng time before it reached that cut out point of 185 or so. So I don't want to kill my battery I just want to reduce the heat in the engine bay to a reasonable limit. I am pretty sure I have heard of people with 3rd gens they can use the power FC to run their fans for a set amount of time after shutdown.
Old 07-18-05, 08:33 PM
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A temp switch will be fine.

My car naturally cools down under 180 in an hour or two in the shade.

ALSO.
It will only run for as long as the temp at the sensor is over 180. If it's in your radiator then don't worry. The fan will cool it down quickly even though it's 115 out here.

You have to remeber. Even if it's 115 out here. It's still a temperature differential of 70!! Heat naturally tries to even it self out so it will cool down.

If your really worried then run it like that for a week.
Just watch it and see if you get a drained/low battery/slow starts/or if it stays on for more than a half hour.
Old 07-19-05, 01:34 AM
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I think I am going to wire the temp switch with a 12v wire instead of using a ignition wire that way the fan with run until the temp drops below the set point, but I will put a switch on the 12v wire that way I can still have control whether or not the fun runs. This way I can try it out and see how long the fan has to run to cool the car down and if it is taking to long then I can just flip the switch to cut the fan. I am only really worried about the fan running to long during the summer. During the winter I don't see any problems. Also, my fan is a dual speed fan and I am going to wire the a/c to trigger the high speed on the fan.
Old 07-19-05, 01:42 AM
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Piece of cake you can get a realy with a timer built in. I was going to go that route when i finaly get an e-fan. Just rig it like a regular relay, set it for the number of minutes you want it to run, then go to temp sensor. If temp drops below say 180 fan goes off. If not the relay with run for say up 20 mins after the car shuts off then goes click and no more current draw and no dead batt.
Old 07-19-05, 01:49 AM
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or just get a inverted/vented hood like crashdumy and I. We're in AZ also but are using vented hoods. Its unbelieveable how much hot air escapes from the vent after I shut off my car, especially when the fan stays on.
Old 07-19-05, 02:15 AM
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Vented hoods cost so much money though..And I can't find one I like ;[
Old 07-19-05, 02:57 AM
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Originally Posted by Jaiyurai
or just get a inverted/vented hood like crashdumy and I. We're in AZ also but are using vented hoods. Its unbelieveable how much hot air escapes from the vent after I shut off my car, especially when the fan stays on.
Once I sell the CF TII hood and get a Vmount setup I'll be in the cool vent hood group :P
Old 07-19-05, 09:26 AM
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Where can you find relay with a built in timer?
Old 07-19-05, 11:32 AM
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Like I said before whe n you shut your car off it only stays on for about 45sec the thermo switch works perfect in 100 degree wheather one of the best mods I've done other than the 3rd gen alt
Old 07-19-05, 01:36 PM
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This is here the big advantage of the EWP comes in!
That´s the main reason why I´ll be running a Davies Craig water pump in my setup!
Really nice to be able to circulate the water after shut down.
Old 07-19-05, 01:54 PM
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Take a look at http://www.aaroncake.net/rx-7/efaninstall.htm . It has instructions for connecting a thermostatic switch directly to a 12V source, thus keeping the fan running for a short period after the car is shut down (assuming it's hot enough). It helps with heat soak, and curbs that large temperature spike that occurs just after shutoff. But it really only matters if the car is already very hot (as it would be in AZ).

Be warned though that if the thermoswitch sticks, the fan will continue to run until the battery is dead.

Edit...BTW, coolant continues to circulate through the block (and through the rad, if the thermostat is open) even after the engine is shut down. This is due to convection currents.
Old 07-19-05, 03:08 PM
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Originally Posted by dennis blackstone
Like I said before whe n you shut your car off it only stays on for about 45sec the thermo switch works perfect in 100 degree wheather one of the best mods I've done other than the 3rd gen alt
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Old 07-19-05, 04:40 PM
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Originally Posted by Aaron Cake
Edit...BTW, coolant continues to circulate through the block (and through the rad, if the thermostat is open) even after the engine is shut down. This is due to convection currents.
why thank you aaron. i was going to say something along those lines. that's how those olde tyme-y cars used to cool. it works like a lava lamp, except its all coolant. thank god they switched to a more practical way to flow coolant.
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