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post #1 of 63 Old 08-03-2021, 10:09 AM Thread Starter
agear
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2 electric fan questions

1st I have only 2 wires total coming from my pair of electric fans. Can I just use 1 relay ?

2nd , what temp should I set them to come on and shut off ? I'm wiring them to my sniper efi .


1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
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post #2 of 63 Old 08-03-2021, 10:21 AM
StoneTower
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What fan are you using? You do not want to overload the relay. Are their instructions with your fan? If it is a Ford Contour fan setup, we can help you with that.

You need to know how much each fan draws so you do not overload the relay. If the fans individually draw a lot of current on startup, you could use 2 relays and use the same trigger wire to turn both relays on at the same time from the Holley Sniper. This would also keep at least one fan working in the event that you ever had a relay failure. 30 amp relays are much cheaper and much more common than 70 amp relays.
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post #3 of 63 Old 08-03-2021, 11:11 AM
cglax6
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This is what I did on my Sniper setup with dual electric fans:

I used a different relay for each fan. The Sniper allows you to control 2 fans separately, so you can set the on or off temps the same for each fan, or you can turn one on at a higher temp than the other. I run a 195 thermostat on my 351w, so my first fan turns on at 205 and turns off at 200. My second fan turns on at 210 and turns off at 205. At idle on a hot day, it'll idle anywhere between 204-208, so both fans will keep it happy when it's hot out.

I bought my relays from Painless (P/N 30133). Remember that the Sniper uses ground triggers, so you'll need a ground trigger relay.

Don't put 2 fans on 1 relay. You're asking for trouble.

I don't recommend turning them on at the same temperature. You may get a big enough voltage drop that will screw with the Sniper. If the Sniper gets anything lower than 12v, it may shut down on you. Startup draw on a fan is much greater than when it is running.
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post #4 of 63 Old 08-03-2021, 01:12 PM Thread Starter
agear
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Ok thanks fellas. I have the flexalite dual fan jeep cj kit from jegs.

http://www.jegs.com/i/Flex-A-Lite/400/116461/10002/-1

It came with a VSC or variable speed controller im currently using but no relay. Must be made into the vsc.

Update. As I'm replying to this thread I see that there are 2reds and 2 blacks coming from the fans themselves but they the 2 red wires jusy connect to one wire and the 2 black wires just connect to one wire on the vsc. . The idea was to do away with vsc and just use 1 relay and use the sniper to turn it on. But I see now I may just use 2 relays . Having said that pair of auxillary leds just use 1 relay

The description says 22 amp draw

Update. I also have this

http://www.jegs.com/i/JEGS/555/10570...iABEgIZQfD_BwE

If I have to use 2 relays then I'm on the fence about it now. Because that's running more wires and that would make my 4th relay for add ons. I would like to take advantage of the efi but I also need to clean up the wiring .
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20210726_165231_1628017514989.jpg   20210726_171218_1628020295625.jpg  

1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
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post #5 of 63 Old 08-03-2021, 06:40 PM
StoneTower
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We need more pictures of the wires. At least I would to understand what is going on. Are you saying that there is more than 2 wire coming from each motor of the fan motors?

If there are 2 wire coming from each fan motor, run the red wire to the #87 pin on one of the relays. Run the black from the fan to a good ground. I usually run the black wire for the fans back to the battery negative terminal. Do the same for the other fan on a separate relay. Run a wire from the battery to pin #30 for each relay. This should be a larger wire #10 or #12. I run a #10 for each relay. You could run a single larger (maybe #8) wire and then split it off to each of the relays pin #30s. You would control the ground on the relay with the Sniper on pins 85 of each relay. Pins 86 on the relays go to the positive on the battery. The Sniper switches the relay by controlling the ground to the coil on the relay. You can get fancy and jumper the pin 86 to the #30 pin to make it cleaner. The #86 only needs a few millivolts to pull the relay in and you have a heavy wire supplying pin #30 because of the fan load. I solder and shrink wrap all the connectors before I out them in the relay sockets. Pin #86 just gets a small 18 gauge wire that comes out of the #30 pin wire.
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post #6 of 63 Old 08-03-2021, 09:16 PM
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The ground path back to the battery can be via the battery terminal but if you take the battery in and out etc you may find it starts to wear and unravels. This little black wire could be transmitting as much as 50 Amperes of current on start up so needs to be secure if you do not want it to give problems. To put it in perspective, that is more than the Amps your alternator has ever produced and it has a thick wire to carry it.

I would look at how your ground straps are arranged and where the cable from the battery negative attaches to the engine and use the same point or where the frame is grounded. That may mean you need a large ring terminal for your cable.

As you probably appreciate, all wires in a circuit need to be the same size including grounds as current circulates. attaching it to a screw in the grille and hoping for a path through some rusty bodywork is not reliable and may impact the performance of the fan.

BagusJeep lives in Bali with far too many 4x4s:
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
1980 Land Rover Series III 109" troop carrier - ROVER
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post #7 of 63 Old 08-04-2021, 01:34 AM Thread Starter
agear
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I can do the 2 relay and efi thing. What temps do you reccomend I turn the fans on ? I hacmve ac so I want to take the heat away from condenser good.

1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
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post #8 of 63 Old 08-04-2021, 02:51 AM Thread Starter
agear
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Quote:
Originally Posted by StoneTower View Post
We need more pictures of the wires. At least I would to understand what is going on. Are you saying that there is more than 2 wire coming from each motor of the fan motors?

If there are 2 wire coming from each fan motor, run the red wire to the #87 pin on one of the relays. Run the black from the fan to a good ground. I usually run the black wire for the fans back to the battery negative terminal. Do the same for the other fan on a separate relay. Run a wire from the battery to pin #30 for each relay. This should be a larger wire #10 or #12. I run a #10 for each relay. You could run a single larger (maybe #8) wire and then split it off to each of the relays pin #30s. You would control the ground on the relay with the Sniper on pins 85 of each relay. Pins 86 on the relays go to the positive on the battery. The Sniper switches the relay by controlling the ground to the coil on the relay. You can get fancy and jumper the pin 86 to the #30 pin to make it cleaner. The #86 only needs a few millivolts to pull the relay in and you have a heavy wire supplying pin #30 because of the fan load. I solder and shrink wrap all the connectors before I out them in the relay sockets. Pin #86 just gets a small 18 gauge wire that comes out of the #30 pin wire.
I'm gonna look at my relays to see what you're saying. In the meantime ; can I just hook up my relay grounds to the sniper blue and green wire
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1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
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post #9 of 63 Old 08-04-2021, 06:43 AM
cglax6
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I put my relays on the engine side of the front clip on the passenger side. The fuses went on the inside of the passenger fender. All wires were run with mesh wire loom and looks just fine. I'll try to remember to get a picture after I get home this evening.

I know you're concerned with having so many relays, but you're not going to get away with having 2 fans controlled by the Sniper with less than 2 relays.
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post #10 of 63 Old 08-04-2021, 09:52 AM Thread Starter
agear
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Quote:
Originally Posted by cglax6 View Post
I put my relays on the engine side of the front clip on the passenger side. The fuses went on the inside of the passenger fender. All wires were run with mesh wire loom and looks just fine. I'll try to remember to get a picture after I get home this evening.

I know you're concerned with having so many relays, but you're not going to get away with having 2 fans controlled by the Sniper with less than 2 relays.
Thats cool 😎. Don't worry about the picture . I cant see 1/2 the thumbnail pictures on this site

1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
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post #11 of 63 Old 08-04-2021, 10:42 AM
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Quote:
Originally Posted by agear View Post
Thats cool 😎. Don't worry about the picture . I cant see 1/2 the thumbnail pictures on this site
You're in Norfolk?!?! I work in Norfolk!

Shoot me a PM and we can link up some time soon and I'll bring my CJ. At the very least, PM me your number and I can text you pictures...and feel free to ask whatever questions you have.
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post #12 of 63 Old 08-04-2021, 04:57 PM Thread Starter
agear
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I have another question. Since this kit came with a variable speed controller. Do I need that ? If I just use 2 relay harnesses will they operate at full power. The reason I'm asking is i want them to run at full power and also don't want to burn anything up.

I could put my speed controller back on there if necessary

1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
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post #13 of 63 Old 08-04-2021, 06:53 PM
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You can run without a variable speed controller and just switch them on and off.

However you will want to operate at 2 different power settings, one say which comes on at 205 F and a higher one at 215F when the heat load is higher. The reason is that these fans take a lot of Amps and the alternator has to top up the whole system, and the alternator takes engine power when it is generating electricity. Using a speed controller, dual independent temperature switches or whatever will improve performance by reducing alternator loads.

I understand the Sniper allows you to do this, to have a low power setting where one fan operates and a high power setting where both work. Therefore you do not need the variable speed controller if you are just going to rely on the Sniper.

BagusJeep lives in Bali with far too many 4x4s:
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
1980 Land Rover Series III 109" troop carrier - ROVER
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post #14 of 63 Old 08-05-2021, 01:47 AM Thread Starter
agear
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Quote:
Originally Posted by BagusJeep View Post
You can run without a variable speed controller and just switch them on and off.

However you will want to operate at 2 different power settings, one say which comes on at 205 F and a higher one at 215F when the heat load is higher. The reason is that these fans take a lot of Amps and the alternator has to top up the whole system, and the alternator takes engine power when it is generating electricity. Using a speed controller, dual independent temperature switches or whatever will improve performance by reducing alternator loads.

I understand the Sniper allows you to do this, to have a low power setting where one fan operates and a high power setting where both work. Therefore you do not need the variable speed controller if you are just going to rely on the Sniper.
Hi bagus. I didn't see where the sniper allows to adjust speed but It can control when they come on. Like I said I want to take heat away from my condenser as much as I can I think. I have a 192 or 193 thermostat. Having said that I'd like to keep engine temp down that much if I can. Having said that when should I have each fan come on ? And a couple of my harness wires are 14 gsuge. Ketone power and relay ground
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1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
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post #15 of 63 Old 08-05-2021, 02:41 AM
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Quote:
Originally Posted by agear View Post
Hi bagus. I didn't see where the sniper allows to adjust speed but It can control when they come on. Like I said I want to take heat away from my condenser as much as I can I think. I have a 192 or 193 thermostat. Having said that I'd like to keep engine temp down that much if I can. Having said that when should I have each fan come on ? And a couple of my harness wires are 14 gsuge. Ketone power and relay ground
I think if you look up that variable speed controller you will find it is not changing speed up and down, it has two settings.

Your system will be normal at about 195-220 degrees F. with a 15-16 lb pressure cap and a 50:50 mix of glycol coolant and water. We all worry if the temp gauge starts to rise but most of the time we would be happier with a lamp that never came on.

If you have a thermostat set at 192 it will start to let water pass at that temperature, may be fully open at around 205. They do not spring open at 192. This will give you an approximate 195 degrees F at the thermostat.

If you set the first fan at 192, and the sensor is in the thermostat housing (that is where I put secondary sensors on a 258, using a 4.0 housing) reading 192, it will overwork the fan which will be on all the time.

I would set the first at a high normal range, so in normal cruise it will not be on, say 210F ON, turning off at 200F. This will give you better mileage. The second one about 220 to 225 ON, OFF at 210 to 215F. this will rein in the coolant at the upper operating limit.

An A/C condenser should not be in contact with a radiator. As it is in front the air flow will keep it from being warmed appreciably by the coolant.

BagusJeep lives in Bali with far too many 4x4s:
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
1980 Land Rover Series III 109" troop carrier - ROVER
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