need help with fans!!!
Thread Starter
Rotary Enthusiast
Joined: Jan 2006
Posts: 1,147
Likes: 1
From: lima, oh
need help with fans!!!
ok so here is the deal. the guy i bought my car from had some crazy *** fan mod done to it. it has two aftermarket 4 blade fans that run through some weird box that is wired directly to the battery and is attached to my m2 intake. ive never seen anything like it before. anyways the inner workings of this box caught on fire and i lost one fan. when i pushed on this box the other fan comes on. so i open this box up and see that everything in there is fried. bare wires and what not everywhere. anyways here is my question:
the fans motors have only 2 wires. power and ground. so my question is would there be any harm in running the fans to a switch so that once the car warmed up i could flip the switch and run the fans at high all the time until i shut the car off or would that have some adverse effect and run the car too cold? any help will be VERY appreciated.
also i will add pics later of what everything looks like if anyone is interested.
the fans motors have only 2 wires. power and ground. so my question is would there be any harm in running the fans to a switch so that once the car warmed up i could flip the switch and run the fans at high all the time until i shut the car off or would that have some adverse effect and run the car too cold? any help will be VERY appreciated.
also i will add pics later of what everything looks like if anyone is interested.
Warming the planet.
Joined: Dec 2004
Posts: 845
Likes: 2
From: Chico, CA
The coolant themostat will not let the temp drop below 180, but there are many low cost aftermarket fan controllers out there. What if you just forget to turn on the switch one day?
If really want them to run all the time just use a properly sized relay trigered by the ign. switch.
If really want them to run all the time just use a properly sized relay trigered by the ign. switch.
That box was a relay of some sort. Relays allow you to use a small switch (which can only handle a small amount of power) to flip a big switch (which can handle a lot more power).
There are two reasons to use a relay:
1. Keep the high-power wires as short as possible.
2. Keep the high-power switch far away from the user, for safety purposes.
Just like fuses and wire, relays are rated to handle a certain amount of current. I would guess that your relay saw more current than it was rated for. It's very possible that the previous owner didn't use the proper relay, or that the fans malfunctioned or shorted out. A stuck fan will draw more current than a properly running fan.
Anyway, I do NOT recommend bypassing any relays. Replace your broken relay with one that can handle at least 1.5x the current rating of the fans. For instance, if you're using two fans, each rated for 20A , use one 60A relay to drive both fans, or two 30A relays (one per fan).
I'm not sure how the previous owner built things, but if I were to design a simple fan-control system from scratch, it would use a temperature-controlled switch (Thermoswitch) to activate the fans. The RX-7 has an OEM thermoswitch that you can use, which will turn the fans on around 105C (221F), or you can use the thermoswitch from an FC RX-7, which will activate the fans at 95C (203F).
-s-
There are two reasons to use a relay:
1. Keep the high-power wires as short as possible.
2. Keep the high-power switch far away from the user, for safety purposes.
Just like fuses and wire, relays are rated to handle a certain amount of current. I would guess that your relay saw more current than it was rated for. It's very possible that the previous owner didn't use the proper relay, or that the fans malfunctioned or shorted out. A stuck fan will draw more current than a properly running fan.
Anyway, I do NOT recommend bypassing any relays. Replace your broken relay with one that can handle at least 1.5x the current rating of the fans. For instance, if you're using two fans, each rated for 20A , use one 60A relay to drive both fans, or two 30A relays (one per fan).
I'm not sure how the previous owner built things, but if I were to design a simple fan-control system from scratch, it would use a temperature-controlled switch (Thermoswitch) to activate the fans. The RX-7 has an OEM thermoswitch that you can use, which will turn the fans on around 105C (221F), or you can use the thermoswitch from an FC RX-7, which will activate the fans at 95C (203F).
-s-
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