How-To/DIY: Simple Engine Bay Radiator Fan Switch for Drag Racing
08-09-2010, 02:58 PM
#1
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How-To/DIY: Simple Engine Bay Radiator Fan Switch for Drag Racing
Ok, so there is another how to on how to wire up an in cabin switch so you can turn on your radiator fan anytime, but this is much more simple so I thought I'd show everyone how I did it.
For those of you who don't know what this is or why one would choose to do this mod, the reason is this: when I go to the track, I want the option of running my fan both when the AC Compressor isn't on, and when the car is completely turned off (not even the key turned on), so that my engine stays as cool as possible whilst I wait in line to race.
Ok, so first of all, locate the plug for your fan. There are 2 fans, but this write-up only shows wiring for one (my 2nd fan doesn't work, and I need to order a new one... but until then, I'm running on just the one). Unplug fan, and cut back rubber wire housing to expose 4 wires.
Use a utility knife to expose a small amount metal on the red wire. Solder some wire to this red wire running to the fan plug.
Now run the wires as shown in the picture below (this is just a rough placement (obviously) to show how the switch is wired). Run another length of wire to the positive terminal of the battery (I used a ring terminal crimped to the end of the wire to attach it to the battery).
Hide wires and switch and you're done! I put mine right in front of the battery. Works like a charm. If you're wiring up both fans, just do the same for the other one and run the wire to the same terminal on the switch. Takes no time at all and is really simple. Enjoy a cooler engine and faster drag times!
For those of you who don't know what this is or why one would choose to do this mod, the reason is this: when I go to the track, I want the option of running my fan both when the AC Compressor isn't on, and when the car is completely turned off (not even the key turned on), so that my engine stays as cool as possible whilst I wait in line to race.
Ok, so first of all, locate the plug for your fan. There are 2 fans, but this write-up only shows wiring for one (my 2nd fan doesn't work, and I need to order a new one... but until then, I'm running on just the one). Unplug fan, and cut back rubber wire housing to expose 4 wires.
Use a utility knife to expose a small amount metal on the red wire. Solder some wire to this red wire running to the fan plug.
Now run the wires as shown in the picture below (this is just a rough placement (obviously) to show how the switch is wired). Run another length of wire to the positive terminal of the battery (I used a ring terminal crimped to the end of the wire to attach it to the battery).
Hide wires and switch and you're done! I put mine right in front of the battery. Works like a charm. If you're wiring up both fans, just do the same for the other one and run the wire to the same terminal on the switch. Takes no time at all and is really simple. Enjoy a cooler engine and faster drag times!
I'll also be adding this to my to do list.
I might be going to the track on friday, so I might get to use my switch mod!
08-10-2010, 07:36 AM
#7
08-10-2010, 08:18 AM
#9
08-10-2010, 11:03 AM
#12
But when the ECU sees such high temperatures does it not alter ignition and fuel timings? I tried this once in my brothers 2007 Frontier by setting the temperature to -50 and it flooded itself and took forever to crank back up.
08-10-2010, 11:08 AM
#13
No, I only use it in between dyno runs, or in the case of the OP, between drag runs. So basically, it can be done while the car is off. Also, haven't had a problem with that other voodoo. Since once you turn the car back on, the Cipher needs to remember what ECU it's hooked up to again and basically starts back @ square 1.
And yeah, I'd say it would do some bad stuff to other things if you did this while running (fail safe, etc that occurs post 210ºF IIRC)
Cripes.... Cipher is only 200$ these day.s
I and I think a few other members paid 2x that.
And yeah, I'd say it would do some bad stuff to other things if you did this while running (fail safe, etc that occurs post 210ºF IIRC)
Cripes.... Cipher is only 200$ these day.s
I and I think a few other members paid 2x that.
Last edited by NmexMAX; 08-10-2010 at 11:11 AM.
08-10-2010, 11:17 AM
#14
No, I only use it in between dyno runs, or in the case of the OP, between drag runs. So basically, it can be done while the car is off. Also, haven't had a problem with that other voodoo. Since once you turn the car back on, the Cipher needs to remember what ECU it's hooked up to again and basically starts back @ square 1.
And yeah, I'd say it would do some bad stuff to other things if you did this while running (fail safe, etc that occurs post 210ºF IIRC)
Cripes.... Cipher is only 200$ these day.s
I and I think a few other members paid 2x that.
And yeah, I'd say it would do some bad stuff to other things if you did this while running (fail safe, etc that occurs post 210ºF IIRC)
Cripes.... Cipher is only 200$ these day.s
I and I think a few other members paid 2x that.
What I do between dyno runs is actually leave the car running with the A/C on and I keep a high current car battery charger connected to the battery to help relieve some of the load on the alternator. The last time I dynoed a friends Maxima I left the A/C on all of the time, even during the dyno. The compressor will disengage automaticaly when the car goes to WOT and @ 50mph the ECU will power down the cooling fans. Although on the dyno I would rather have a way to keep them running constantly. Most dyno places I have been to do NOT have adequate airflow.
08-10-2010, 11:21 AM
#15
I think we touched base on this subject at one point, but neither one of us had tried anything yet. It makes sense. Also, when we use radiator fans we're not trying to fan the engine, but rather cool the coolant off in the radiator, but, it would also help create more aifrlow in the instance of a dyno run .. I would think.
08-10-2010, 11:23 AM
#17
08-10-2010, 11:25 AM
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I think we touched base on this subject at one point, but neither one of us had tried anything yet. It makes sense. Also, when we use radiator fans we're not trying to fan the engine, but rather cool the coolant off in the radiator, but, it would also help create more aifrlow in the instance of a dyno run .. I would think.
Last edited by jowo9; 08-10-2010 at 11:29 AM.
08-10-2010, 11:30 AM
#20
You also don't exactly have to solder wires. You can remove the fan relays and make a few jumper wires with male spade connectors. I have never made jumpers for all of them but I used to jump just one of them that would power up one fan in low speed mode. It wasn't really adequate for the dyno though.
08-10-2010, 11:33 AM
#21
08-10-2010, 11:33 AM
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You also don't exactly have to solder wires. You can remove the fan relays and make a few jumper wires with male spade connectors. I have never made jumpers for all of them but I used to jump just one of them that would power up one fan in low speed mode. It wasn't really adequate for the dyno though.
08-10-2010, 11:45 AM
#24
I don't want to risk the life of my multimeter to try to measure what is probably more than 10 amps starting current.
Last edited by SR20DEN; 08-10-2010 at 11:47 AM.
08-10-2010, 11:52 AM
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I tried to put together an external power supply made of six laptop power supplies (20v 4.5amp) to run one fan independently and it would not work. The current draw was too much at that voltage. I just want to know what a real world basic current draw is on these fans at 12 volts so I can better calculate how much current supply I would need to run them independently at 16 volts.
I don't want to risk the life of my multimeter to try to measure what is probably more than 10 amps starting current.
I don't want to risk the life of my multimeter to try to measure what is probably more than 10 amps starting current.
08-10-2010, 12:32 PM
#26
http://www.powerstream.com/Wire_Size.htm
08-10-2010, 01:13 PM
#27
I tried to put together an external power supply made of six laptop power supplies (20v 4.5amp) to run one fan independently and it would not work. The current draw was too much at that voltage. I just want to know what a real world basic current draw is on these fans at 12 volts so I can better calculate how much current supply I would need to run them independently at 16 volts.
I don't want to risk the life of my multimeter to try to measure what is probably more than 10 amps starting current.
I don't want to risk the life of my multimeter to try to measure what is probably more than 10 amps starting current.
08-10-2010, 01:42 PM
#28
08-10-2010, 02:30 PM
#32
Because if you have a short at your switch or in your wiring your car could catch fire. Well, probably not fire but it would spark until you removed the short or disconnected the wire at the battery. Ever install a car amp? You want a fuse as close to the battery in case the wire shorts to ground. As it is now, you have no protection in that wire in case of a short.
20 amp should work.
20 amp should work.
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