Electric Fan Placement Push or Pull?

mike d · Feb 21, 2008

Ive got my 95 4runner with a 4.3 in it. Doing the cooling right know. I got rid of the mechanic fan didn't have room for it. Anyways I was wondering how people have been mounting there Electric Fans. I have room for either side of it meaning in front of the Radiator or Behind Radiator. The fan I have can be set up for either a pusher or puller.

Also, since i got rid of my Mechanical fan, do you guys set your temp relays to kick in at whatever 170 185 or do you just have them run full time when you have the ignition kicked over.

Any input would help.

Thanks

skrause · Feb 21, 2008

Pull whenever possible, with a shroud if at all possible. Always, doesn't matter what's turning the blades. Push is a last resort and is less efficient.

44newman · Feb 21, 2008

Pushing causes the splatter effect.
Pull is the way to go.

mike d · Feb 21, 2008

Thanks for the info.

mike d · Feb 21, 2008

Do you run these full time, or have them kick on at certain temps?

CrustyJeep · Feb 21, 2008

skrause said:
Push is ... less efficient.

44newman said:
Pushing causes the splatter effect.
Pull is the way to go.

Elaborate, both of you. No really... Huh?

skrause · Feb 21, 2008

CrustyJeep said:
Elaborate, both of you. No really... Huh?

No, you can just blindly take my word as gospel. :fawkdancesmiley:

CrustyJeep · Feb 21, 2008

skrause said:
No, you can just blindly take my word as gospel. :fawkdancesmiley:

Only in the chatter box :flipoff:

MIG'DHORSE · Feb 21, 2008

at slow speeds it doesnt matter as much id imagine. if you have it on all the time, i could see the fan rotating opposite being a problem or inefficient at higher speeds. just my input.

LuckyBoyOne3 · Feb 21, 2008

I like to set the fans up with a 195 on/180 off, with a manual over ride "ON" switch, Push or Pull I've never noticed a difference on the street

CrustyJeep · Feb 21, 2008

MIG'DHORSE said:
at slow speeds it doesnt matter as much id imagine. if you have it on all the time, i could see the fan rotating opposite being a problem or inefficient at higher speeds. just my input.

"Pusher" refers to the fan pushing the air through the radiator, but it doesn't imply pushing it against the natural direction of flow. That would be silly.

Not Jobless · Feb 21, 2008

Fans pushing air through the radiator are less efficient and should only be done when installing a secondary fan.

If you would all do a little research on something called "static pressure" you would learn a lot and stop wasting your time with pusher fans and thinking that the CFM rating actually means something that will help you

skrause · Feb 21, 2008

Jobless said:
Fans pushing air through the radiator are less efficient and should only be done when installing a secondary fan.

If you would all do a little research on something called "static pressure" you would learn a lot and stop wasting your time with pusher fans and thinking that the CFM rating actually means something that will help you

Actually I found some test results last night that said pushing cold air through the radiator was more efficient than pulling warm air. Something about the cold air being more dense and 4% better performance, and then a bunch of nerdy stuff that I didn't understand. Oh, they also said shrouds only improve cooling by 2%. :redneck: :haha: :haha: :stirpot:

Not Jobless · Feb 21, 2008

skrause said:
Actually I found some test results last night that said pushing cold air through the radiator was more efficient than pulling warm air. Something about the cold air being more dense and 4% better performance, and then a bunch of nerdy stuff that I didn't understand. Oh, they also said shrouds only improve cooling by 2%. :redneck: :haha: :haha: :stirpot:

I don't get it?

The air coming from the front of the vehicle (during forward motion) will be the same temperature regardless of whether you're using a pusher or puller fan...

Shrouds only increase by 2%? You fond some BS data dude!

A fan will draw air in from the path of least resistance. Without a shroud that will not be through the radiator but from around the edges of the fan, therefore providing no cooling.

CrustyJeep · Feb 21, 2008

Jobless said:
Fans pushing air through the radiator are less efficient and should only be done when installing a secondary fan.

If you would all do a little research on something called "static pressure" you would learn a lot...

Wat?

The term "static pressure" is far too vague to be of any use whatsoever here on it's own. What do you mean? Still not seeing a difference between a pusher and a puller that anyone but a pocket protector wearing nerd would even bother mentioning.

cheesemaker · Feb 21, 2008

Use a puller fan, and try to get one that covers as much of the radiator as possible. The more air resistance in front of the radiator the less cooling affect the radiator has. Anywhere the fan would be touching in front of the radiator, there would be considerable loss in heat exchanging properties, basically you might loose 10 to 15% cooling affect (off road). And a fan shroud ensures that you are pulling the air through the radiator and not from around it.
The general consensus is 195*on/180* off, some kits can be manually adjusted depending on your driving style. Set it up with a manual override switch to have on or off. If your crossing a river or going through mud you want it off. So, find a three way switch, off/auto/manual on.

GRNTACO · Feb 21, 2008

If you use a pusher wouldn't you want to have a shroud to keep the air from deflecting off the radiator?

skrause · Feb 21, 2008

Jobless said:
I don't get it?

The air coming from the front of the vehicle (during forward motion) will be the same temperature regardless of whether you're using a pusher or puller fan...

Shrouds only increase by 2%? You fond some BS data dude!

A fan will draw air in from the path of least resistance. Without a shroud that will not be through the radiator but from around the edges of the fan, therefore providing no cooling.

The air that has come through the radiator is warmer than the air going in. I didn't say any of this, they did. :fawkdancesmiley:

MIG'DHORSE · Feb 21, 2008

CrustyJeep said:
"Pusher" refers to the fan pushing the air through the radiator, but it doesn't imply pushing it against the natural direction of flow. That would be silly.

now it makes sense. oops. now i understand your inquiry. i apologize for my waste of time.:awesomework:

Not Jobless · Feb 21, 2008

CrustyJeep said:
Wat?

The term "static pressure" is far too vague to be of any use whatsoever here on it's own. What do you mean? Still not seeing a difference between a pusher and a puller that anyone but a pocket protector wearing nerd would even bother mentioning.

Do your own research Glen, I used to spec and source cooling fans for a living. I know all I need to about Current Draw, Static Pressure, CFM, etc...

If you honestly believe that the same fan ran either as a pusher or a puller will provide the same cooling results than you are grossly misinforemd, sorry.