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Discussion Starter #1 (Edited)
After Extensive talk with William, SilverMK2, James, and Jake (ABQMK2) I have a Diagram for those whom would like to do this mod and get rid of the Stock fan clutch. So far from all the People that I have talked too these fans are among the best and very Inexpensive.

This fan setup requires (2) 30/40A Relays and (2) 30A fuses. The reason I suggest this route instead of using (1) 30/40A Relay and (1) 30A Fuse for both fans is so that if one fuse was to pop then you would still have a fan that would be running and atleast keeping the engine from Extreme overheating. This has worked well for others and Im sure it will work well for those who want to venture this direction and get rid of the Stock fan clutch. If you live in a Hot climate like myself (El Paso, TX) then running these fans and any other fan that you have would be in your best interest.

Let me know what you all think about this setup and again, thank you William, SilverMK2, ABQMK2 for supplying the fans and my Friend James (Jeeves) for Designing this Diagram and for helping me get this up and going for you all...



Robert
 

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...just an FYI, that fan will run non-stop with the factory thermostat. When running a 192degF thermostat, it's smart to have the fans kick on at 200+deg. Even mid-summer, my fans never kick on until I drop below 20mph, no need running them if you don't have to unless you like changing alternators.

...and most thermostatic switches are rated as "on" higher than off, I've never seen it the other way around... For example, ON at 210, OFF at 190 meaning they kick on when temps hit 210deg, and don't turn off until 190. ...this is called, uh, I don't remember, but without it the fans would kick on and off and on and off and on and off.

Another suggestion would be giving the thermo-switch constant 12v, not b+, as it will allow your car to cool the engine bay down more quickly, and cool the block via convection, helps resolve some heatsoak issues as well. I've run my turbo car this way for a while, and it runs for 2-3min after I shut the car off even after a 1min idle cool down. ...I run the smallest battery I've ever seen in a supra relocated to the trunk, and I've NEVER had a low battery issue because of it.

That's all...

--billyM
 

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Discussion Starter #4
This is not a Factory Temp Probe, This Probe is a Electric Fan temp Sending unit that William has linked to his Diagram. It turns on at 185 Degrees and turns off at 170 Degrees. I will correct that in the Diagram The probe in the Pic is just an Example of where to install this one. Ive been told to use the B+ is the best place to draw power from.

JAKE.... The main person that got both his and my Fans. Thanks a Million bro.....
 

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If you run the + side of the temp probe off the B+, the fans will NOT run when the key is off (which I find to be very helpful keeping the engine bay cool and minimizing heat soak). I highly suggest running the + side of the temp probe straight to the battery (through a small fuse) so the fans will run ANY time the coolant temp is high enough, regardless of key.

Again, you will want to make sure your thermostat is a slightly lower temperature than your temp probe, so you won't be running constantly. With the stock 192deg thermostat, that diagram will run NON STOP which is not only wasteful (alternator drag anybody), but absolutely unnecessary. Even with a 180deg thermostat, that fan may kick on when you come to the first stop after warm-up, and never kick off (because the thermostat will make make sure the temp probe never sees below 180deg, while the temp probe needs to see 170 before it shuts off).

I'd like to see a cross-flow radiator with dual fans wired in a series with a 195deg probe to one, and a 200deg probe to the other, running a 180deg thermostat. That way, only one fan would only kick on and run up to the point that it was not able to cool sufficiently, and the second would kick in. ...probably a little bit overkill, but I'd like to do that...

--BillyM
 

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i run no thermostat at all in my 7mgte. havent for years. takes a lil bit longer to warm up but other then that it is fine. im in fla though and manual so never have issues.

also, you want the wire from the b+ in your diagram to go through the relays before the fan switch as the switch is usually just a 1 wire and grounds itself when threaded int othe engine.
 

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The 180/170 switch work fine on my car. The stock thermostat starts opening around 180. The switch is mounted aft of thermostat so it won't turn on till the stat opens anyhow. I'd pull switched power out of the fuse box as well. The diagnostic block seems kind of ghetto rigged to me.
 

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For a nomially 17.5A motor which may require more current depending upon the load (back pressure due to mechanical configuration it blows into) it sees (and 17,5A spec could easily have a unit to unit variation of 10%) you should have a minimum of a 30A fuse. In general fuses should be rated at a minimum of 150% of the maximum expected load.

Also, I suggest that you use a variable temp probe as dannymk2 just suggested. This way you can adjust the temp on a very hot day at maximum engine load such that the fan turns on when cabin temp guage just starts to move up from the normal operating position and then back off the temp adjustment a few degrees (both temp and probe pot rotation). Then you'll get minimum fan turn on time. I had a NA setup with a single fan placed in the same physical location (side to side and also front to back) as stock that would not turn on at idle for 5 minutes on a 85 drg F day. I realize that there's less physical free volume on a turbo setup and max load may be the highest under hood temp condition.
 

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the adjustable fan swtiches have a probe that has to be slipped into a radiator hose or in between the radiator fins. the switch i recomended is what is installed on camaros and corvettes etc.. as the stock one runs much too hot for performance aps. i dont see the issue wit ha fixed temp switch. i am also going to have a separate relay installed on mine so that whe nthe a/c is on the fans will both run regardless of engine temp. and im getting rid of the small pos fan that is stock for the a/c. itll give more room for the i/c and oil cooler and also be MUCH more efficent for my a/c system.
 

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Hi, I'm James/Jeeves the guy who actually created the diagram.

There are several issues with the diagram, I hadn't seen the actual temp probe that was planned to be used and I wasn't aware that it would be posted for everyone before everything was solidified.

However, here's my comments real quick:
the adjustable fan swtiches have a probe that has to be slipped into a radiator hose or in between the radiator fins.
I used to use one of those, then I upgraded to a gigantic Koyo aluminum radiator. I'm sorry, but I refuse to shove a temp probe into the fins of my gorgeous, brand new radiator. So, I've been looking for other solutions.

For a nomially 17.5A motor which may require more current depending upon the load (back pressure due to mechanical configuration it blows into) it sees (and 17,5A spec could easily have a unit to unit variation of 10%) you should have a minimum of a 30A fuse. In general fuses should be rated at a minimum of 150% of the maximum expected load.
I don't know the low-voltage code, but on 120VAC circuits the NEC code specifies a 120% rating. Seeing as how I could run them a 35A fuse w/o blowing a 20A fuse is already alloting a decent gap for load/short protection. And having tested it, I can state that the day to day load varies VERY little.

If you run the + side of the temp probe off the B+, the fans will NOT run when the key is off (which I find to be very helpful keeping the engine bay cool and minimizing heat soak). I highly suggest running the + side of the temp probe straight to the battery (through a small fuse) so the fans will run ANY time the coolant temp is high enough, regardless of key.
IMO, this is a poor idea. The only manufacturer I know that runs a radiator fan after power-off is Volkswagen, and that's in their vehicles that have electric water pumps (so that they can actually flow coolant for several minutes after shut off).

In reality, you've got no coolant flow, and you're only cooling the coolant in the radiator core itself while that in the block/turbo (if you're still on the stock ct26), sits there and heat soaks everything.

Tapping relay power off of B+ insures that these 30-40A draw fans only run as long as your turbo timer (and alternator) does. Nothing will ruin your day more than your temp sensor failing (which I've had happen) or too much fan usage on a weak battery, and having your car be dead when you try and go somewhere later.

I might also add that these fans are puller fans, so they will draw hot air into the engine bay and not really help much with heat soak. Heat soak comes from a number of issues, the temp of the coolant in the core isn't primarily one of them. Hot exhaust manifolds, hot oil and coolant sitting in the block, (in the 7M) poor intake plenum placement, and several other issures are far more prominent.

As I said, there are some issues in the diagram, it was rough and not 100% accurate. With the sensor I was linked to, I believe it'll be pulling the contact to ground to activate (as it's really only got pole, whereas the one I was thinking of had two), so I'll likely have it drag the relay's coil ground to that pole. It's low load, and should be fine on the sensor then when the temperature is made it'll pull that contact to ground, and cause the relays to engage.
 

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In regards to the value of the fuse, would it not make sense to just use the stock value that ford issued with the contour, as long as the wiring stayed the same? The fan does not draw current in a straight line, it spikes at intial draw and then tapers off. I was told as general rule of thumb 14 fan" or less, 30 amp....16" 40-50.
 

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I'd like to be the 1st to welcome jeeves to the forum..even though youre a non-mk2 guy ;)

Jeeves is a very good friend on mine and supraguy31. he has a bitchen MK3 and is an admin guy on www.racingsouthwest.com it is an awesome forum and i would like for everyone that can join to do so!

He also does good head....on my 7mgte head that is along w/robert...LOL...you guys are awesome..thanks.

now the heat soak thing....if you run your fan after the car is shut off it has to help a little by blowing across the engine and cooling it off some more right?
 

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now the heat soak thing....if you run your fan after the car is shut off it has to help a little by blowing across the engine and cooling it off some more right?
Without taking readings it'd be tough to say. I think the internal factors account for far more than the residual temp. On top of that, it'll be sucking radiator temp air into the bay (and without the car moving) it'll have no vacuum to draw that same air back out. I largely think those fans are moot to preventing heatsoak.

In regards to the value of the fuse, would it not make sense to just use the stock value that ford issued with the contour, as long as the wiring stayed the same? The fan does not draw current in a straight line, it spikes at intial draw and then tapers off. I was told as general rule of thumb 14 fan" or less, 30 amp....16" 40-50.
It would, but wiring conditions will also potentially add more draw. I also don't know the stock rating. In my testing they would pop a 30A fused before they reached full speed, but wouldn't pop 35A through a day of driving. So, I'm running a 40A in there right now, never had a problem.
 

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interesting. my contour fans have 30amp fuses each currently and dont pop. 1 fan would run on a 15amp fuse and the other a 20amp. the initial current spike of 1 fan is a lil higher then the other for some reason. i just went with 30amp each to simplify it and if either fan shorts the fuse will blow no prob. also im running 40 amp relays to be sure if they do short only the fuse will go out.
 

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Discussion Starter #18
I just went and bought (2) 30/40A Relays and (2) Spade fuse blocks so I can get this thing Installed.

On a Side note, I did look through summit racinf catalog and found another temp probe. In the notes, It states thatt his is a 2 Spade temp probe instead of a Single like the one everyone is using. Not for sure if this really matters but the temp control is the same.
http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRF-30111&N=700+115&autoview=sku

Robert
 

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another good idea that ive seen done with e-fans is to wire in a switch, so that if your temp sensor/probe fails, you can just manually turn on the fan. i believe i have a wiring diagram that dodge truck guys use when they do lincoln mark viii fan conversions and viper fan conversions if anyone is interested in seeing it.
 
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