Guest Anonymous Posted July 28, 2001 Share Posted July 28, 2001 I may have just doine something stupid. If so, please chastise me lightly, I'm still learning. I have just installed an electric fan and shroud in my Z. Its a 1 speed junkyard fan, that I believe is out of an 89 ford tempo. I have set it up as a pusher, in addition to the engine fan. I tried to set it up as a puller, but it would not fit between the radiator and water pump. I wired it straight to the battery for now, with a toggle switch on the dash so I can just turn it on when I have to sit. It sure blows a lot of air, but it seems to run very fast and loud, so I am wondering if I should have hooked it to a lower amp(?) circuit. So... am i going to set my car on fire? Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 28, 2001 Share Posted July 28, 2001 Guys, one of the reasons these Ford fans cool so well is because the blades are design to pull alot of air. But it takes a heck of a motor to turn it. The Cobra GT 4.6L fan I have pulls 35 amps on high. The Cobra electrical system has a special box that controls the AC and fan, and it has relays and a 60 amp fuse in it. I'd seriously think about using that switch to actuate a relay near the fan. And I'd run a fusible link and probably at least a 10 gage wire from the ALT/Battery to the relay, from the relay to the fan, and grounding the fan with a 10 gage wire. Of course, put a fuse in there too! BTW, if you use wire size of 10 gage, you need a 14 gage fusible link. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 29, 2001 Share Posted July 29, 2001 I"m with Pete - use a relay on that puppy. the Z electricals are strained enough without us adding things to them. A relay will take nearly ALL of the load off the stock systems. I tend to use fuses rather than links myself but I'm far from an expert on which is better or why. Pete if you know more about the Cobra setup please do tell. I expected this fan to be two speed but instead it appears to be single speed with two hot inputs. The motor is supposedly Cobra. No matter, it blows like mad and I expect ZERO problems with cooling my beast. If I could get two speeds I'd be much happier though... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 29, 2001 Share Posted July 29, 2001 I'm running 12 gauge wire from the fan, and I think that's OK, as it's a little larger than the wire leads from the fan motor. I need to upgrade the toggle switch though, as the leads to it are a smaller guage, and it gets real hot real quick while the fan runs. It was the best in stock at the hardware store at the time, though. I'll go look for a hardier one tomorrow. The 12 gauge wires don't get hot, so I think they are OK. I'm not sure I understand how to set up a switch that actuates a relay near the fan. There is nothing else on that circuit, because I ran a wire from one lead of the fan straight to the battery (interrupted by the switch) and the other lead to ground. Again, if this is dangerous, please let me know. I will wire a fuse into the circuit tomorrow when I replace the switch. The motor has no stickers to tell the AMPS and RPMS, so I will try a 35 amp fuse and see if that holds. Thanks for the help. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 29, 2001 Share Posted July 29, 2001 YES, this is dangerous. The switch will burn out it's contacts - when I was younger I killed many switches running foglights, now I know better. If it's getting hot that's "bad". Fuse should be as close to the power source as possible, like right by the battery. The reason for this is that if any portion of th ewire leading from the battery to the fuse gets grounded the wire from that point back to the battery WILL burn. I've learned this through experience too and until the wire breaks or the power is removed it will continue to burn. Relays aren't hard. They are pretty simple in design and consist of a switch that's closed by an electromagnet. Buy a setup that would be used for foglights, the amperage shoudl be high enough. The package should have a wiring diagram on it - substitute the fan for the lights Power to activate the relay should be fused and so should the power for the fan itself. Pete likes fusible links and can tell you where to put those if you want to use them instead - probably much the same way. I'd draw a picture but have no tools at my disposal or place to post a pic right now. If you use the relay setup you could even set it up such that the power for the switched side comes from a circuit that's hot only when the key is on - then you wouldn't have to remember to turn the fan off when you park. At some point you may want to setup a thermal switch for that fan. If it's your only means of keeping it cool I certainly would as a few moments of inattention and engine temps could climb. If it's just an auxilary fan then it's not so bad. I use both on my setup. A thermal switch and a manual one that overrides it (shrug). Hrm, have to see if it shuts off with the key or not but as loud as it is I don't think forgetting will be a worry! Good luck! I wired many circuits just like you did and learned the hard way. The relays make life much easier! Quote Link to comment Share on other sites More sharing options...
Guest kc6wfs Posted July 29, 2001 Share Posted July 29, 2001 Hi Brian, Just be sure it's on the fused side and you should be fine. Fans do run around 10k rpm and make noise. Mine makes a lot of noise. Even if it's on a 30amp circut that should be ok. Look on the sticker and it should say how many rpm's and amps it pulls then figure out what else is on that circut and then you can figure out what amp fuse to run. BUT be sure you are running proper gauge wire before and after the fan. Feel the wire after it's been running and see if it gets hot. If so double the gauge of the wire. Bigger is always better for electrical stuff. Dave Booth Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted July 29, 2001 Share Posted July 29, 2001 Pete, I recently burned up my Taurus two speed fan. Used inline fuse and fuseable link, think fan was just ready to go. My question for you is where did you get cobra fan? Wrecking yard, from Ford? If you dont mind how much do the cobra fans go for as Im running into trouble finding replacement Taurus fan two speed type. Thanks Mike Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 29, 2001 Share Posted July 29, 2001 Thanks all. BLKMGK, Sorry, I don't think my question was clear. I understand that the hot switch is dangerous. I am replacing that today. My question was "once the switch is upgraded and a fuse or link is installed in the circuit, is wiring it straight to the battery inherently dangerous?" I now believe from reading all above that the answer is "no". This is an auxillary fan that I intend mostly to keep the car from overheating at long stoplights and in stop and go traffic. At some point I plan to ditch the mechanical fan and the junkyard electric, and get a Flex-a-lite Black Magic unit. That almost $200 solution will have to wait for a bit, however. There seems to be an inclination for some to use fusible links over fuses, or vice versa. Does one have an advantage over the other(for any application, not just this one), or is it just a preference? Thanks! Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 29, 2001 Share Posted July 29, 2001 quote: Originally posted by Brian_O: My question was "once the switch is upgraded and a fuse or link is installed in the circuit, is wiring it straight to the battery inherently dangerous?" I now believe from reading all above that the answer is "no". There seems to be an inclination for some to use fusible links over fuses, or vice versa. Does one have an advantage over the other(for any application, not just this one), or is it just a preference? Thanks! Your first statement is correct - it is not inheritently dangerous, so long as you place the fuse or link as close to the battery as possible. In other words, keep the length of unfused wire to a minimum. Fusible links are inexpensive and easy to install. Also, they can handle higher current circuits. However, they are not terribly reliable, and it is difficult at best to predict at what current level they will actually blow. There is a reason that you don't see fusible links anymore in modern cars. That said, they are still better than nothing. Fuses have much more predictable behaviour, but they are more complicated and expensive to implement. You need to use a fuse holder (obviously), and find a place to mount it, such that it is reasonably well protected from the environment. When our cars were designed, the current state of the art in fuses didn't have a reliable, cost effective way of handling high current (say, > 30A) circuits, but fusible links handled this pretty well. Today, you can get an automotive grade 'Mega' fuse, that is capable of handling up to 200A, but they are pretty expensive. All else equal, I would always opt for a fuse. In your case, you should only require a ~40A circuit (or less), so I would try to go with an inline automotive grade fuse. If you can't find a fuse holder with big enough leads, try looking at the fuse holders that are being used with some of the high end stereo equipment - they are kind of expensive, but they will accomodate 8 or 4 gauge wires with ease. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 29, 2001 Share Posted July 29, 2001 Getting my fan is a story in itself. I used th eJunkyardDog finder on the 'net to get it but when it shipped (for like $20!) it was just the motor. Doh! Then my friend's motor fried - he'd had a Cobra fan in his truck. Before talking to me he yanked it and I wandered through the shop just after he had replaced it with a different fan. The pieces of th efried Cobra unit were on the bench and when I told him I had a motor for HIM he gave ME the pieces. So, I now have a Cobra fan but it's apparently just one speed. when I quered JunkyardDog for Taurus fans I got MANY replies in the $30 range so... Brian, running the juice straight from the battery, through the fan, and through the switch is NOT as safe as using a relay. You're requiring a small switch to handle large loads and being forced to run high current capable wire into the cabin. If it shorts expect big problems. A relay will let you use any switch you want (I use the old defrost switch) to switch a much larger current sucking device SAFELY. As for fusible links over fuses, Pete can best speak to this as I'm honestly not very familier with fusible links and have always used fuses. If Pete prefers links I have nop doubt he's got his reasons and can educate us both as to why they might be better. As for that BlackMagic fan, other than the name I don't much like them. As you noted they cost like $200 and they will NOt moce as much air nor last as long as an OEM fan out of a Taurus (6cyl w/AC - 2speed fan) or Mustang (I've got a Cobra fan). Th eOEMs care much more about cooling their cars than Mr Gasket does about cooling yours. The BlackMagic fan DOES have some nice features like a thermostat and easy mounting but I've bought a screw in thermostat for mine for about $8 from Jeg's (replacement sensor for one of their expensive setups) and I mounted mine using tips from Pete and about $20 worth of stuff. I've got less than $80 in my fan and I can feel the breeze form it standing BEHIND my car with the hood off. It sucks paper from the ground to the radiator and holds it there firmly. I couldn't believe it but when I walked back to the front of the car there was paper stuck to the front. You can buy fans like these online cheap or stroll through the junkyard. I've got pics on my site as to how I mounted mine and so does Pete. If you hunt around here you'll see our discussions, my agony over how to do it, and the URL for Pete's setup w/pics. I followed his method mostly and it works just fine. Best of all if the motor goes I can get another to replace it pretty easily. Do bear in mind that it DOES suck bigtime juice - hence my relay(s) and fuses. Cobras had BAD overheating problems in past years due to engine size in the bay, airflow issues, and HP output. One of the Ford band-aid solutions was a giant fan. I'm more than happy to reap the benefits of that - this fan minus the frame ears that I cut off is almost as large as my radiator. I anticipate no cooling problems so long as it spins. If anyone needs better pics or explanations of mounting I'll be happy to take them or explain.... Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 29, 2001 Share Posted July 29, 2001 quote: Originally posted by BLKMGK: Brian, running the juice straight from the battery, through the fan, and through the switch is NOT as safe as using a relay. You're requiring a small switch to handle large loads and being forced to run high current capable wire into the cabin. ...Oops. I agree with Blkmgk on this. I was only considering the safety of getting the current directly from the battery. You should definitely still use a relay. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 30, 2001 Share Posted July 30, 2001 Heh, we posted at the same time As for fuse holders... my fan doesn't have them I've got a harness that has male blade connectors slid onto a 40amp "mega" type A/C fuse. The downside of this is that changing it is a PITA and right now both circuits for the fan go through this in a cascade sort of circuit. I need to buy a spare before I hit the road just in case. Fan shouldn't see 40amps but ya' never know. BTW - I now see why the Howe radiators cool so well. Silly thing takes OVER 3 GALLONS of coolant it looks like. That's not including what's in the motor either. Filled the antifreeze jug three times and it still had some room at the top! Whew, them's some big tanks... Quote Link to comment Share on other sites More sharing options...
RPMS Posted July 30, 2001 Share Posted July 30, 2001 Heya, Brian. One other thing to consider regarding the use of a relay in place of just a switch is current drop. Depending on the gauge and length of your wire, as well as the soundness of your contacts and the internal resistance of your switch, you may notice some loss in efficiency that will make a noticeable change at the fan itself. If you run heavy gauge wire to a relay near the fan, you'll probably get noticeably better performance. For evidence of this, notice how many people with stock wiring complain of dim headlights. Just a thought. Oh, and where in Dallas are you located? Us Hybridz folks in the Metroplex aught to get together sometime for beers/burgers. [ July 29, 2001: Message edited by: RPMS ] Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 30, 2001 Share Posted July 30, 2001 a few replies: zfan: I bought it new at a dealer. The parts guy was intrigued with the project and gave it to me for super wholesale or something like that on the ticket. I paid $175 for it. That's alot, but it kicks but and I wanted to make sure I had reserve cooling since I was putting A/C in. I think the regular price is like $250. (list) --- BLKMGK: I agree with TimZ, the Maxi fuses are nice (I'm using one on my fan - a 60 amp.) I just ran fusible links in a few places cause that's what I knew to do. I agree it'd be better to just have used fuses. I think the only advantage a fusible link has is that it is kind of forgiving if you have a quick short when working on something (like less than a second when you touch a hot wire to ground, see a spark, and then take it away.) But there are slow blow fuses also. BTW, the Camaro Rad takes about 1.5 gallons - less weight up front - but not alot of reserve for cooling with this thing. Oh, I photocopied a few pages (including the circuit diagrams for the cooling fan) from a Haynes (I think it was) at the local Trak Auto. That's where I saw the relay box and 60 amp fuse info. --- Brian_O: A switch that can handle 30 amps (what some of the Ford fans pull on high speed) is plenty expensive. A relay is not that much. Plus all the length of wire to run to and from the switch drops voltage. There are auto electric sites, books, etc. that can show you how to install a relay. And you can buy them in radio shack, with plug in connectors. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 30, 2001 Share Posted July 30, 2001 Yeah, I ordered mine from Radio Shack online, (30 amp relay for the Fan) it was cheap like I think 10.00 or so for the relay and plug. I'd never wired one before and it wasn't hard although they don't give instruction, between what I read on the net and the schematics it wasn't to tough to figure out. Regards, Lone Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 31, 2001 Share Posted July 31, 2001 Guys, check out the link I posted in Misc. Tech for the EFI connectors. They've got the NICE Bosche relays listed and while the prices are decent (IMO) the best part is they actually HAVE them. I had little idea where to get them form when needed them although I seem to recall at least one person having a link for them. That site has som good weatherpack connectors and other things. Way cool! Quote Link to comment Share on other sites More sharing options...
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