I did a search and didn't find anything, but in reading a recent post, I came across this reply that made me wonder... push or pull??

[High speed= good temp
Low speed/idling = temp rise means your fan is not pulling enough air thru the radiator. Either the fan clutch isint working right or your missing shrouding allowing air to bypass the radiator. At speeds above 30mph, the fan becomes useless as the impinging air is enough to keep the engine/radiator cool.]

So, does it really matter what direction the fan sucks/blows or does only matter that it does either one to do it's cooling job?

And if it makes a difference as to whether or not it's electric or belt-driven, I have a belt-driven one now, but I'm going to get an electric fairly soon.

Thanks!

--Jeff

 

Fans are generally designed to pull. If at all possible keep them pulling.

Unless its belt driven, in whihc case its desinged to push, the real trick is spooling a belt to get in front of the radiator.

 

are thier any links to the electric fan mod?

 

They are more effecient as pullers. Leznay, search arund here, theres lots of detailed e fan mods.

 

EFan should be in the FAQ sticky thread at the top of the forum.

 

I don't think it'd make sense for a fan to push air, as it would be against the flow generated by the motion of the car. Also the air coming thru the front would be cooler than the air in the engine bay.

 

Hehehe.

The fan would push air from the FRONT of the radiator. Does that make sense now?

 

yes it makes sense, no i dont think it would work better. Because air is entering thru and cooling the radiator, so putting something in front of it is not cool, it would just block air flow.

 

Puller fans (that is, fans behind the radiator, unless you are building a demo derby car the airflow is ALWAYS front to back) are more efficient for three reasons:

The air is generally moving in a straight line (more efficiently) if the fan is behind the radiator than in front.

More radiator surface is exposed to incoming air, instead of being partially blocked by fan. Yes the fan will still distribute the air, but the air that gets distributed has to first get through the fan's frame... and if you have the fan close enough to not suffer from bleedout, likely there will still be "dead" spots in airflow.

And a minor one - the air that the fan moves is heated slightly by the fan blades beating the air up. Better that be after the radiator than before.

 

There is a BMW with a big fan infront of the radiator I saw. I looked to be 8 bladed and didnt have much around it. The motor was on the side of the radiator.
P.S. the air still went front to back though, and its possible to double up with fans, small infront, big in back(engine bay side) If i'm not mistaking they tell you to do that on some aplications.

 

Auxiliary pusher fans are not uncommon on OEM's. Rarely are they ever the main fan.

 

To Add, they are sometimes "pusher" fans that work for smaller items, like the air conditioning system.

 

Oh! I C

 

i run an e-fan on my 3. it's mounted against the rad on the grill side blowing thru the rad. cools just fine while moving and fan off and will idle for hours with the fan running without running hot. with the fan behind the grill, it has that "mercedes" look to it.

 

It's weird this discussion comes up every now and then.
Basicly, it's not making any difference wether you have a puller or pusher fan. You must just decide what you prefer/can mount (sometines it's just easier to use a pusher, sometimes a puller will be the logic step) and then get the correct setup.
They only thing you can't do is use a puller in front of the rad, or a pusher behind.
For the rest it makes absolutely no difference.

 

are there specific fans that are pushers o puller?

or can you just flip the around?

 

You just reverse the polarity. On some you have to remove the the fan from the motor and flip it around as the blades are contoured a certain way.

 

Hmm, quite a few fans are EITHER push or pull. Reversing the polarity will make it turn the other way around, but won't have the same air-displacement. Only a few types can be used either way, by flipping the blades. If you look at the specs of aftermarket fans, it'll be specified if it's a push or pull (or either if the blades are reversable)