Electric fans for cooling engine
Pro
Joined: Apr 2005
Posts: 603
Likes: 2
From: Illinois, USA
Originally Posted by jbs75
This is not a trick statement, and based on an engineering background, is what I feel is required. All I'm saying is that it's alright to attempt to shoot holes in what I said; but at least explain why you disagree. I'm trying to pick everyone's brain on this subject.
I don't know why a higher output waterpump would help unless there are corners in the block where coolant has a chance to almost stop, and create a hot spot. Circulating the coolant faster(assuming the radiator is doing it's job) should have little effect. You will get slightly warmer coolant into the radiator but it shouldn't have that big of an impact.
Jim
I don't know why a higher output waterpump would help unless there are corners in the block where coolant has a chance to almost stop, and create a hot spot. Circulating the coolant faster(assuming the radiator is doing it's job) should have little effect. You will get slightly warmer coolant into the radiator but it shouldn't have that big of an impact.
Jim
I don't know if that takes place at 10% or 50% or 200% flow rate, but you can go too fast.
As far as fan placement to the radiator ...that will all depend on the shroud design. If moving the fan back 2" will put it in a location where the fan tips about 1/8" clearance, it will be very effective compared to right agaist the radiator with large air gaps.
I don't consider myself any sort of expert, but like many, I've had some experience here and there.
Brian.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Ha Ha....a friend drove his 71 Camaro,electrc fans and all to El Centro this past weekend.it was 120 down there...on the way back,climbing a very steep hill,his temp hit 260....he stopped,poured water on his radiator to cool things down but after 20 minutes,decided to go up the hill....after getting on top in 100 degree weather,his engine temp was at 230 or so,and he went down hill in neutral...he made it home...no leaks,no nothing..just freakin hot...
Race Director
Joined: Jun 2000
Posts: 10,042
Likes: 674
From: FL
Originally Posted by jbs75
A single fan with no shroud should be a problem with overheating. I had tried that years ago but the air never left the engine compartment. Adding a shroud and sealing all the extra holes in the sheet metal around the radiator fixed that.
How sealed was this engine compartment. Fans don't move air out of the engine compartment, they pull it through the radiator. Adding a shroud and sealing the holes ensured that the only air the fans could pull had to come throught the radiator vice around it.
BTW, how do you reconcile the above statement with your initial statement that the fan should be 2-3" from the radiator?
Racer
Joined: Dec 2001
Posts: 328
Likes: 0
From: Dallas County Texas
You can't convince him SG....fans exist to cool the
engine bay....and you darned well know it!!!
The only reason the radiator is there is to be a nifty solid temperature sender housing to bolt those fans too!
The only reason the radiator is there is to be a nifty solid temperature sender housing to bolt those fans too!
Racer
Joined: Jul 2004
Posts: 450
Likes: 0
From: Fredericksburg VA
Ok I'm going to do the unpopular thing and defend a part of what he said. Having the switch in the radiator makes perfect sense. Turning the fans on because the engine is hotter isn't necissarily going to do anything what cools the engine is the radiator cooling the fluid which cools the engine. Therefore it would seem to me that if the fluid inside the radiator was hot turning the fans on would help cool it, but if the liquid was already cool enough turning on the fans would not necissarily add any benefit. I may be completely wrong or I may just be completely misunderstanding but my limited (for right now as I'm in school) engineering would make this make sense. But I will be the first to admit I'm certainly not an expert on the subject, or with cars in general for that matter. I haven't even made the move to electric fans yet and when I do I'll be posting here to ask all of your advice so don't hold it against me for giving my input and trying to stand up for the small guy. 
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Racer
Joined: Jul 2004
Posts: 450
Likes: 0
From: Fredericksburg VA
I will say as well while the fans are there to cool the radiator, if done correctly with a shrowd they should pull air through the radiator and have the ability to be angled over the top of the engine and maybe help circulate air, and maybe help cool the air coming in the intake? Not at all sure on that one, but it makes sense in my head. 
Racer
Joined: Dec 2001
Posts: 328
Likes: 0
From: Dallas County Texas
Except intake air should be external, not internal
(one of my next steps is cowl induction) and this is common on vettes.
I don't even really think cooling the engine bay is a bad idea - I just think it's not at all crucial - sortof like hi-cap window washer fluid...
I don't even really think cooling the engine bay is a bad idea - I just think it's not at all crucial - sortof like hi-cap window washer fluid...
Drifting
Joined: Nov 2002
Posts: 1,665
Likes: 1
From: Ontario
Originally Posted by jbs75
"...the air never left the engine compartment.
Originally Posted by soccer794
...maybe help cool the air coming in the intake?
I just gotta plug my own custom fan post:
My custom electric fan setup
Melting Slicks
Joined: Feb 2003
Posts: 3,053
Likes: 4
St. Jude Donor '03,'11
Originally Posted by WayneLBurnham
displacement air pump taking 100+ hp to turn you'd have a pretty good analogy.... 
you can only move so much air with a 1/8 hp electric fan. The engine driven fan can tap 5 - 10 hp from the engine and move a whole lot more air.
where did you get your degree.......at Sears?
Captain, i can't change the laws of physics.
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
CFM's are CFM's whether it is coming from a 1/8th H.P electric fan or a 300 H.P. fan. If the electric fans are pulling the necessary cfm's to adequately cool the rad. what is the diff?
Let this guy try his theories until he hits the ones that work. That what each one of us has done to have a car that doesn't overheat and that is the bottom line.
Bernie
Let this guy try his theories until he hits the ones that work. That what each one of us has done to have a car that doesn't overheat and that is the bottom line.
Bernie
Thread Starter
Instructor
Joined: Jun 1999
Posts: 213
Likes: 0
From: Chapel Hill NC
Originally Posted by SteveG75
"The air never left the engine compartment" WTF?
How sealed was this engine compartment. Fans don't move air out of the engine compartment, they pull it through the radiator. Adding a shroud and sealing the holes ensured that the only air the fans could pull had to come throught the radiator vice around it.
BTW, how do you reconcile the above statement with your initial statement that the fan should be 2-3" from the radiator?
How sealed was this engine compartment. Fans don't move air out of the engine compartment, they pull it through the radiator. Adding a shroud and sealing the holes ensured that the only air the fans could pull had to come throught the radiator vice around it.
BTW, how do you reconcile the above statement with your initial statement that the fan should be 2-3" from the radiator?
Thread Starter
Instructor
Joined: Jun 1999
Posts: 213
Likes: 0
From: Chapel Hill NC
Originally Posted by soccer794
Ok I'm going to do the unpopular thing and defend a part of what he said. Having the switch in the radiator makes perfect sense. Turning the fans on because the engine is hotter isn't necissarily going to do anything what cools the engine is the radiator cooling the fluid which cools the engine. Therefore it would seem to me that if the fluid inside the radiator was hot turning the fans on would help cool it, but if the liquid was already cool enough turning on the fans would not necissarily add any benefit. I may be completely wrong or I may just be completely misunderstanding but my limited (for right now as I'm in school) engineering would make this make sense. But I will be the first to admit I'm certainly not an expert on the subject, or with cars in general for that matter. I haven't even made the move to electric fans yet and when I do I'll be posting here to ask all of your advice so don't hold it against me for giving my input and trying to stand up for the small guy.
Race Director
Joined: Jun 2000
Posts: 10,042
Likes: 674
From: FL
Originally Posted by jbs75
What happens with no shroud or sealed area around the radiator, the air will take the path of least resistance which will happen to be through the holes around the radiator, and BACK THROUGH the radiator around the fan with no shroud. This is when you are standing still, and this actually is the problem time. When you are moving the fan, shroud, and holes are mostly unimportant. What's really important then is your spoiler under the nose. This not only helps force air up into the front of the radiator, but creates a low pressure area behind the spoiler to scavenge the engine/transmission area and promote more air flow through the radiator..
1) I never break 200.
2) I run at about 185 on the highway and the fans don't come on (above 30 mph).
3) Around town the fans cycle.
I have driven cross country in the middle of summer twice with this setup. 70 mph, 3000 rpm, 100 degrees outside, no problems. Next year with OD, 75 mph, 2200 rpm, 100 degrees outside, no problems.
My fans are tight to my radiator. My radiator is sealed all around. My fan switch is in the thermostat housing.
Results speak louder than theories.
Racer
Joined: Dec 2001
Posts: 328
Likes: 0
From: Dallas County Texas
Um...you tried to compare a cooling fan to a BLOWER
....and to think all this time all I had to do was make a housing for my flexfan and I wouldn't have to drop $3K on an 8-71 setup!
....now try the OTHER med....
Just because it could take 5-10 hp to run does not mean it really does or that it uses it effectively. Mechanical fans do essentially nothing past a certain relatively low rpm and they do even less at low rpm.
I, and anyone else, verified that the first time at low speed after a mechanical to electric fan switch. Are you honestly so arrogant you think the rest of us have so much money we change to these things just for something to waste money on? I was extremely reluctant to switch to electric - I don't like the reliability issues of electric vs. flywheel - but it greatly improved my cooling (although it did not solve the heating issue entirely.)
Just because it's attached to a belt doesn't mean it delivers some huge amount of air flow. I wouldn't be surprised that the water pump pulls the most of the power off of that belt anyhow.
Incidentally, you'd probably be hugely interested to know when the 28V and 42V system changes were all being discussed for upcoming GM models to be (like the C6) one key option was electric braking and another was electric supercharging It didn't occur, yet, so we don't know how well that works....
....now try the OTHER med....
Just because it could take 5-10 hp to run does not mean it really does or that it uses it effectively. Mechanical fans do essentially nothing past a certain relatively low rpm and they do even less at low rpm.
I, and anyone else, verified that the first time at low speed after a mechanical to electric fan switch. Are you honestly so arrogant you think the rest of us have so much money we change to these things just for something to waste money on? I was extremely reluctant to switch to electric - I don't like the reliability issues of electric vs. flywheel - but it greatly improved my cooling (although it did not solve the heating issue entirely.)
Just because it's attached to a belt doesn't mean it delivers some huge amount of air flow. I wouldn't be surprised that the water pump pulls the most of the power off of that belt anyhow.
Incidentally, you'd probably be hugely interested to know when the 28V and 42V system changes were all being discussed for upcoming GM models to be (like the C6) one key option was electric braking and another was electric supercharging It didn't occur, yet, so we don't know how well that works....
