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2/27/2019 1:53 PM  #26


Re: Electric Fans

Like I mentioned before you need to figure out the in-rush current. This is different from the sustained current, that will answer your question on if it's OK to power both at the same time.

**BUTT** I will say, to me, your best bet is an aftermarket controller that gives you the flexibility AND simplicity you're looking for.

 

2/27/2019 3:39 PM  #27


Re: Electric Fans

1fstang,  I used the Volvo fan controller pictured with a Contour fan.  I used a VW temp switch that was mounted in the lower radiator hose, using a 90's Saab radiator hose that had the temp switch bung. (didn't want to take the radiator out again). Took me a couple of switches to get the desired on/low/high/off conditions.  Worked flawlessly,   for a couple years, until vehicle was sold.  If I had to do it again, I would use the Volvo/Saab/VW components, but I really do prefer the mechanical fan for simplicity reasons.

Last edited by TimC (2/27/2019 3:48 PM)

 

2/27/2019 4:00 PM  #28


Re: Electric Fans

I would relay and fuse each fan separately.  I don't know how much these draw at start up, you could measure it with a multimeter, but I'm going to guess they draw close to 30 amps at start up.  To avoid blowing a fuse you'd have to fuse a combined circuit at 60 amps, and then, if something went wrong with one fan and it shorted causing the fuse to blow the other fan now also wouldn't work even though there's nothing wrong with it.  So, for redundancy alone I'd fuse and relay them each separately. 

Whether or not the fans will operate at multiple speeds depends on a couple things.  A factory system would likely have more than two wires going to fans for such a system (which is what that Volvo fan control system describes).  Now, regardless of whether or not the fans use multiple windings for various speeds you could create a circuit that varied output voltage to in effect govern fan speed.  This could be done several different ways, but the real thing to consider is that by reducing the voltage you are going to be creating heat, because the way you reduce the voltage is by increasing resistance.  I'd be concerned about what that heat could potentially do to the wiring, etc.

IMO, this is all academic.  There's no practical reason to need two fans both operating at multiple speeds.  I still stand by a simple relay system, because there is basically nothing to go wrong, and its easily repaired on the road if needed.  Carry a spare relay and a spare fuse or two and the parts needed in your "just in case" tool kit still fit in the palm of your hand. 

 

2/27/2019 8:48 PM  #29


Re: Electric Fans

Looking back, I didn't answer all your questions.  On the Contour fan, I'm fairly certain both fans run high & low speeds.  You don't want to just wire the high speed circuit because those fans move a lot of air and are LOUD on high speed.  When we got the fans set up with the correct temp switch, the high speed rarely came on, and the low speed cycled nicely.  I researched the OEM wiring for the Contour to figure the fuse size.

I see you found the nastyz28 site.  Here's the ranger station link where we got good guidance.  You can easily put the bung for the temp switch in your empty radiator, which would make your installation a little cleaner without the Saab hose fitting.

https://www.therangerstation.com/tech_library/volvo_electric_fan.shtml

Here's a link from 5 years ago where I listed the part numbers for the temp switches we tried on the last post, #14

http://fyi.boardhost.com/viewtopic.php?id=2272

Last edited by TimC (2/27/2019 9:00 PM)

 

2/27/2019 10:35 PM  #30


Re: Electric Fans

I'm sure those fans were controlled by the computer in the OEM application.  If they are indeed multi speed I wouldn't suggest just hot wiring them to run just the high or low speed.  At that point you are going to need some kind of controller, or a more involved custom built system, but that would require knowing a bit more about the fans. 

 

2/28/2019 12:33 PM  #31


Re: Electric Fans

I have been running the same fans for a wile now, I have a relay per fan and using the Hayden thermostat with no issues. its a good simple setup


65 coupe, 351w, c4, power disk brakes, power r&p, vintage air.
 

2/28/2019 11:48 PM  #32


Re: Electric Fans

This works really well, no power rush. Also some cars are coming out with brush less fan motors
https://ls1tech.com/forums/forced-induction/1906766-variable-speed-pwm-fan-control-under-25-less-diy.html


1965 Notchback, 8.8 rear end, T-5, Diy Front Struts, Shelby Drop, Bumpsteer Kit
 

3/01/2019 3:05 PM  #33


Re: Electric Fans

Triton wrote:

This works really well, no power rush. Also some cars are coming out with brush less fan motors
https://ls1tech.com/forums/forced-induction/1906766-variable-speed-pwm-fan-control-under-25-less-diy.html

Thanks for that! Very interesting."Soft" starting is nice. Hmmm I might have to re-do my Megasquirt fan setup
 

 

7/05/2019 8:21 PM  #34


Re: Electric Fans

I'm going to run a Contour fan setup also, gotta do it on a budget for now until I can afford my Holley Sniper setup with the built-in fan control. Would this setup work using the factory built in resistor? See the attached wiring diagram. 

Last edited by 92vanguard (7/05/2019 8:22 PM)


Scott Williams- 1969 Pete Revson tribute
 

7/06/2019 1:55 AM  #35


Re: Electric Fans

I suppose, provided you don't have AC. 

 

7/06/2019 7:12 AM  #36


Re: Electric Fans

92 vanguard, I thought this fan assembly is dual fan , not dual speed. I looked at pictures on the article, that is what I noticed.

 

7/06/2019 10:20 AM  #37


Re: Electric Fans

Nos681 wrote:

92 vanguard, I thought this fan assembly is dual fan , not dual speed. I looked at pictures on the article, that is what I noticed.

I agree, I only see a 2 wire plug. 1 for positive and 1 negative. The shroud is plastic, no ground/negative there. Looks like they turn on and off together. If you want to run the fans separate, you need to rewire and not use that plug. If you want to change speeds, best to go with PWM like Triton posted. You could try a resister pack like on the heater motor to change speed, buy I don't think that would work well on fans of that size. You could do what I did, listen to Steve and through your electric fan in the garbage.


If this forum can't fix it, it isn't broke.
 

7/06/2019 9:40 PM  #38


Re: Electric Fans

Theres a resistor between the two plugs. Low speed to one side and high skips the resistor. Both fans run at the same time. Either high or low speed. AFAIK, the fans ground on a seperate plug. I used to own an SVT Contour and the fans run together, not individually.


Scott Williams- 1969 Pete Revson tribute
 

7/06/2019 9:58 PM  #39


Re: Electric Fans

Awesome!  I will add this to my list. Thanks!

 

7/07/2019 4:47 AM  #40


Re: Electric Fans

That makes sense.  I'm a fan (heh) of its simplicity as well. 

 

7/07/2019 10:47 AM  #41


Re: Electric Fans

I've never designed a circuit before and I just want to make sure that this should work. I have no idea if it DOES work. That's why I posted. 

Also, what would the ideal fan temp trigger ranges be for a 351W based stroker? .060" overbore and 393 crank.


Scott Williams- 1969 Pete Revson tribute
 

7/07/2019 11:17 AM  #42


Re: Electric Fans

The trigger point may require experimentation.  That's why I prefer an adjustable triggering mechanism.  I have mine set at 195, with a 180 degree t-stat in the engine.  This gives the coolant a chance to start circulating before the fan comes on.  This should allow proper circulation because it doesn't cool the coolant so much that it drops below the t-stat closing temp.  I found that even on days with the outside temp in the upper 90s and heat index well over 100 it still never got over 210, and mostly ran at 205 even on those days.  On cold days warm up still happens quickly and it runs closer to 180, which is still good for circulation. 

BUT, your setup may vary based on your radiator, t-stat, water pump, etc. 

One thing I'd advise is inserting a fail safe switch into the trigger wire for the high speed.  This way if something fails you can still trigger the fan by grounding the relay. 

 

7/07/2019 1:27 PM  #43


Re: Electric Fans

TKOPerformance wrote:

BUT, your setup may vary based on your radiator, t-stat, water pump, etc. 

One thing I'd advise is inserting a fail safe switch into the trigger wire for the high speed.  This way if something fails you can still trigger the fan by grounding the relay. 

Stock radiator, but the wider one for AC, stock pump, 185 t-stat. And yeah I forgot to build in a failsafe switch.

IIRC, this pulls 60 amps on startup. Not sure what running speed is.

Last edited by 92vanguard (7/07/2019 1:40 PM)


Scott Williams- 1969 Pete Revson tribute
 

7/07/2019 2:41 PM  #44


Re: Electric Fans

92vanguard wrote:

Theres a resistor between the two plugs. Low speed to one side and high skips the resistor. Both fans run at the same time. Either high or low speed. AFAIK, the fans ground on a seperate plug. I used to own an SVT Contour and the fans run together, not individually.

First of all I lied, didn't through out the old electric fan. Found it while looking for other parts. Your right there is a resister behind that plug and the fans use a separate ground. I don't have the whole harness from the Contour fan but I have the fans, shroud and wires with it. There are some other control wires involved with the fan setup so I'm not 100% sure but I think your diagram would work. I would run a wire from your green wire to both fans positive leg, then a ground to both fans negative leg.


If this forum can't fix it, it isn't broke.
 

7/07/2019 5:24 PM  #45


Re: Electric Fans

Start up amp draw of 60 is to be expected.  I would suppose that running amps are in the 30-40 range.  My Spal fan pulls over 30 amps at start up, but pulls around 22 in operation. 

I would fuse each relay feed with a 40 amp fuse. 

 

7/07/2019 6:10 PM  #46


Re: Electric Fans

TKOPerformance wrote:

Start up amp draw of 60 is to be expected.
I would fuse each relay feed with a 40 amp fuse. 

So if it pulls 60 amps at startup, why would I use a 40 amp fuse?


Scott Williams- 1969 Pete Revson tribute
 

7/07/2019 9:54 PM  #47


Re: Electric Fans

92vanguard wrote:

TKOPerformance wrote:

Start up amp draw of 60 is to be expected.
I would fuse each relay feed with a 40 amp fuse. 

So if it pulls 60 amps at startup, why would I use a 40 amp fuse?

 
The inrush current at startup won’t last long enough to hurt the wiring.


John  -- 67 Mustang Coupe 390 5 speed
 

7/08/2019 4:45 AM  #48


Re: Electric Fans

Hmn, I suppose you'd need a 60-70 amp fuse then if it draws 60 amps on each setting (low and high).  I must be honest though, that seems really high.  My point was fuse it a bit higher than what it draws.  If its supposed to draw 60, but actually draws 61 you will constantly be blowing the fuse and having no fans running.  I would definitely use 10 gauge wire for the feed from the solenoid.  I'd look at the gauge of the factory wiring too though.
 

 

7/08/2019 11:00 AM  #49


Re: Electric Fans

92vanguard wrote:

TKOPerformance wrote:

Start up amp draw of 60 is to be expected.
I would fuse each relay feed with a 40 amp fuse. 

So if it pulls 60 amps at startup, why would I use a 40 amp fuse?

You're right your wiring needs to accommodate that inrush plus some headroom. I'd fuse, wire, and relay for 70-75A. Tyco makes some really nice large amp relays. Although they are a bit spendy. 

Looking around here's a decently priced 70A relay. https://www.a1electric.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=AEOS&Product_Code=DD-RLY-3&Category_Code=

Last edited by Raymond_B (7/08/2019 11:01 AM)

 

7/08/2019 11:03 AM  #50


Re: Electric Fans

Ya know, every time I read through one of these electric fan threads, I'm reminded of all the trouble I went through with mine. I tried 3 or 4 different set ups, and the ones that worked were too loud and ugly, and the neat installation just wouldn't cool enough. Since going to the fixed blade with fan clutch, custom fitted shroud, 30% higher flow waterpump I have had zero issues with engine temperature. I get caught in traffic in over 90 degree heat, even sitting and idiling for long periods and the temp guage stays right at 190 degrees. Although I do kinda regret removing the A/C that the car originally came with. 


It's easier to add horsepower than it is to lose weight.
 

Board footera


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