E-fan: push or pull?
04-27-06, 03:13 PM
#27
Originally Posted by ajhehr
Ive seen as much as 4% (on dyno's) But the more power you make the smaller percentage its going to be. But below 250 I would call it 3% to be safe.
(i got 1hp on my old nissan hardbody)
The major benefit of an electric fan is (also true for an EL waterpump.)
- it pulls a steady CFM
- you can have it cycle (on and off), this helps maintain a steady coolant temp with smaller fluctuation
In order to get the most from an EL fan you must make a cowl for it, as in a "ring" that sits as close to the edge of the blades as possible. If you just have spinning blades with no cowl you operate at 23% (so im told) of the potential of the fan.
Mathematically push or pull CFM IS CFM so as long as your ducting is proper, there should be no difference.
You only really need a cooling fan below 5 mph In the FC's since we have a large inlet I doubt a CF does much good at speed, Anyone who has a Thermostat controlled CF knows that its rarely on while the cars in motion, but most always turns on while at a stop with the AC running.
For instance If your road racing and you are overheating, All the cooling fans in the world will do you no good you simply need better radiator,wp ect.
Personally Im a big FAN (punny...) of a pusher as it leaves the engine bay free of clutter and one less thing to seriously injure people that have no business being in an engine bay in the first place.
(i got 1hp on my old nissan hardbody)
The major benefit of an electric fan is (also true for an EL waterpump.)
- it pulls a steady CFM
- you can have it cycle (on and off), this helps maintain a steady coolant temp with smaller fluctuation
In order to get the most from an EL fan you must make a cowl for it, as in a "ring" that sits as close to the edge of the blades as possible. If you just have spinning blades with no cowl you operate at 23% (so im told) of the potential of the fan.
Mathematically push or pull CFM IS CFM so as long as your ducting is proper, there should be no difference.
You only really need a cooling fan below 5 mph In the FC's since we have a large inlet I doubt a CF does much good at speed, Anyone who has a Thermostat controlled CF knows that its rarely on while the cars in motion, but most always turns on while at a stop with the AC running.
For instance If your road racing and you are overheating, All the cooling fans in the world will do you no good you simply need better radiator,wp ect.
Personally Im a big FAN (punny...) of a pusher as it leaves the engine bay free of clutter and one less thing to seriously injure people that have no business being in an engine bay in the first place.
although you make it sound like you know what you're talking about...
pusher fans lose airflow by the basic need that they have to grab air and force it through where pullers suck air through, testing has shown that pullers are more effective but the difference depends on how they are setup.
your setup is less than desirable also, circular shaped fans lose about 30% of the surface of the radiator for cooling, i am a fan(no pun intended) of fully cowled fans as they cool the complete surface of the radiator for maximum efficiency.
swapping pully load for electrical load is basically the same, while the fan is operating the electrical load is basically the same as a mechanical water pump or clutch fan but is less reliable because electricals tend to fail more than mechanical parts do. why would a single speed water pump be more effective than a mechanical one? higher RPMs generally = more heat generated by the motor, a single RPM pump will either be working too much at idle or not enough at high RPMs to keep up with the cooling needed, a belt driven water pump supplies more flow as needed. you are describing more of a drag car than a street driven daily driver, which isn't appropriate because it is giving people the impression it is something they should do.
a fan should also be matched to the requirements needed, an overly large e-fan can actually put more of a load on the engine than the stock clutch fan would when the fan is on.
the main thing is, you shouldn't install an e-fan unless it is absolutely necessary.
Last edited by RotaryEvolution; 04-27-06 at 03:17 PM.
04-27-06, 07:57 PM
#29
Rotary Enthusiast
Join Date: Sep 2002
Location: Statesboro, GA
Posts: 1,233
Likes: 0
Received 0 Likes
on
0 Posts
Shelby Cobra? that's 60's technology. they didn't even know what aerodynamics were back then and you're gonna trust the way they felt like installing radiator fans? The only smart thing he did was put a big motor in a tiny car. The only thing he did after that was get old.
Puller ownz pusher. Yes, CFM's are CFM's. but that's most likely measured under no load conditions. I guarantee any fan will PULL more CFM's than PUSH.
Puller ownz pusher. Yes, CFM's are CFM's. but that's most likely measured under no load conditions. I guarantee any fan will PULL more CFM's than PUSH.
04-27-06, 09:54 PM
#30
What's the point??
iTrader: (6)
Join Date: Oct 2005
Location: Omaha, NE
Posts: 995
Likes: 0
Received 0 Likes
on
0 Posts
Is it really necessary to sacrifice cooling at speed with a duct that limits flow for more cooling at idle? The engine doesn't give off enough heat at idle to warrant this. In order for the air to get through the entire radiator with a duct it would have to turn at a right angle in a puller config, and it wouldn't even touch parts in a pusher config so... Which really offers more even cooling where it counts?
04-27-06, 10:20 PM
#31
Rotary Enthusiast
Join Date: Sep 2002
Location: Statesboro, GA
Posts: 1,233
Likes: 0
Received 0 Likes
on
0 Posts
by duct you mean shrouding around the fan? if the fan is big enough, then the shrouding won't have an adverse effect on cooling at speed. at least, i had no problems with my fiero fan/shroud setup.
04-28-06, 12:51 AM
#32
I'm a boost creep...
Join Date: Jan 2002
Location: Auckland, New Zealand
Posts: 15,608
Likes: 0
Received 8 Likes
on
8 Posts
Originally Posted by ajhehr
Ive seen as much as 4% (on dyno's) But the more power you make the smaller percentage its going to be. But below 250 I would call it 3% to be safe.
The major benefit of an electric fan is (also true for an EL waterpump.)
- it pulls a steady CFM
- you can have it cycle (on and off), this helps maintain a steady coolant temp with smaller fluctuation
- it pulls a steady CFM
- you can have it cycle (on and off), this helps maintain a steady coolant temp with smaller fluctuation
04-28-06, 03:09 AM
#33
Play Well
Join Date: Feb 2005
Location: We're all fine here now, thank you. How are you?
Posts: 4,218
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Karack
only use a pusher fan if there is no room for a puller, that is the ONLY reason to use a pusher.
Oh i was just goffing around. The cab over truck I work with most of the time have puller fans because the rad is behind the motor.
Thread
Thread Starter
Forum
Replies
Last Post
Jeff20B
1st Generation Specific (1979-1985)
73
09-16-18 07:16 PM
