Is An Electric Fan That Much Better Then The Original Belt Fan
01-25-08, 02:16 PM
#51
Aaron's point is that both the stock fan and e-fan shut off above 25-35mph (or whenever it gets cold), so it's almost pointless to switch. The clutch on the stock fan disengages when cold, so the fan spins but not very much. And yeah, even a good e-fan pushes a lot less air. But a good e-fan is still adequete.
01-25-08, 03:32 PM
#52
I guess I should have worded my post a little better then, huh? lol
When I had an e-fan in the REPU, it had a lighted switch and whenever the truck was driven fast enough to turn the fan while it was off, the light on the switch would light up kinda dimly. Not much of an alternator. More of a generator. See? You can misword posts too.
Even so, it's not much of a generator if it could only light the switch dimly.
The finger protector cage on most e-fans can reduce air flow a little bit so I took the liberty of removing some of the rings as an effort to increase total CFM. I think I cut like half of them. The cage is still plenty strong.
When I had an e-fan in the REPU, it had a lighted switch and whenever the truck was driven fast enough to turn the fan while it was off, the light on the switch would light up kinda dimly. Not much of an alternator. More of a generator. See? You can misword posts too.
Even so, it's not much of a generator if it could only light the switch dimly.The finger protector cage on most e-fans can reduce air flow a little bit so I took the liberty of removing some of the rings as an effort to increase total CFM. I think I cut like half of them. The cage is still plenty strong.
Last edited by Jeff20B; 01-25-08 at 03:39 PM.
01-25-08, 04:14 PM
#54
Jeff the way I see it, even though the fan is almost fully disengaged from the. But as we know it still really spins. When you have the fan spinning regadless of the the clutch being engaged or not, there's a force thats facing towards the engine. As if the fan would want to detach itself from the engine. You can look at it like a helicopter. The fan blades is what makes it go up by moving the air, there for creating an upward pulling force.
With an engine, the force produced is circular. and anyforce perpidencular to that (the fan), will decrease the other force by some amount. Correct? So if the clutch fan spins higher at higher RPMs and drawing more air (even though the clutch might be disengaged), the more air it will draw through it hence increasing the force perpidencular to the engines circular motion.
Atleast thats the way that I see it and makes sense to me. An Efan if it spins just sitting there does not put a load on the engine.
Feel free to correct any of my reasoning
With an engine, the force produced is circular. and anyforce perpidencular to that (the fan), will decrease the other force by some amount. Correct? So if the clutch fan spins higher at higher RPMs and drawing more air (even though the clutch might be disengaged), the more air it will draw through it hence increasing the force perpidencular to the engines circular motion.
Atleast thats the way that I see it and makes sense to me. An Efan if it spins just sitting there does not put a load on the engine.
Feel free to correct any of my reasoning
01-25-08, 04:59 PM
#55
stock fan makes too much noise. even at idle with engine cold that thing is being spun and moving air. it's mechanical clutch does not completely disengage, ever. so it's always sapping some amount of power.
even after buzzing along in 4th gear then letting off the gas that fan is a whirring enough to attract attention. i really like my e-fan, draws less attention and still cools the car.
even after buzzing along in 4th gear then letting off the gas that fan is a whirring enough to attract attention. i really like my e-fan, draws less attention and still cools the car.
01-26-08, 01:48 PM
#56
Who wants to be pisst' on
Join Date: May 2007
Location: Bpt,Ct
Posts: 133
Likes: 0
Received 0 Likes
on
0 Posts
I was thinking of doing this when i change my rad after i turbo. so would this realy be neede so far all i got out of this thread was its not realy necesary but looks nice and is a bit more efficiant but not significantly noticiable.
01-26-08, 02:25 PM
#57
Semantics......really we are arguing over very small gains and losses here, bottom line unless your car is a serious monster, the stock fan works and works well, so spend the money on tires, suspension or brakes and gain a lot more performance on parts that need upgrading.
01-26-08, 08:58 PM
#61
Full Member
Join Date: Nov 2003
Location: San Diego, CA
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
I don't recommend going with an electric fan.
I switch to electric in my 5.0 and have nothing but problems since. Fuses blowing, overheating, wiring problems, fitment, blah blah blah. Save yourself the headache and stick with what Mazda and it's millions of dollars in research and design did. Factory is almost always superior (in quality, fit, finish, duability) than aftermarket.
I switch to electric in my 5.0 and have nothing but problems since. Fuses blowing, overheating, wiring problems, fitment, blah blah blah. Save yourself the headache and stick with what Mazda and it's millions of dollars in research and design did. Factory is almost always superior (in quality, fit, finish, duability) than aftermarket.
01-27-08, 12:13 AM
#62
Technology does improve usually for the better by being more efficient. Sure it might of been good when they designed it 20+ years, but over that time I'm sure alot of development has been made. Why do alot of stock cars now come with E-fans?
As for your 5.0 e-fan swap, the problems sounds like it was more user than product no offence. Wiring can be made as nice or nicer than stock. Blowing fuses could mean you're not using the rated one for that system or just have some sort of short happening. Fitment, they do offer various sizes for a reason. Overheating, they also offer various CFM for a reason. Just sounds like you didn't do enough research on what you're buying.
As for your 5.0 e-fan swap, the problems sounds like it was more user than product no offence. Wiring can be made as nice or nicer than stock. Blowing fuses could mean you're not using the rated one for that system or just have some sort of short happening. Fitment, they do offer various sizes for a reason. Overheating, they also offer various CFM for a reason. Just sounds like you didn't do enough research on what you're buying.
01-27-08, 02:14 AM
#64
Rotary Freak
Join Date: Sep 2002
Location: SF BayArea
Posts: 2,815
Likes: 0
Received 0 Likes
on
0 Posts
Modern cars use Efans because they give designers more placement options and they can be programmed to cool the engine down (well, maybe just the radiator) after it is shutoff.
If your clutch fan makes a lot of noise, especially when accelerating, it is defective. I had one like that: it used to stick partway around. Go to the Pick n Pull on half-price day and get one for about $10. You just need a 10mm socket or combo wrench to undo the 4 screws, and maybe a long screwdriver or something to keep it from turning while breaking those screws loose.
Or you can get one from one of the guys here on the forum.
I have 4 rotarys, one since 1982, and never had a fan fail.
Technically, a lightened flywheel doesn't affect horsepower at all: it just assures that during acceleration more of the engine horsepower contributes to accelerating the mass of the car since less is required to rev up the rotational mass. This benefit disappears at constant speed, so top speed is unaffected, and dyno HP (which is usually read out at constant speed against a brake or an MG set) is also unaffected.
Of course, you can also obviate the benefit of lightened flywheel by revving the engine to best speed at the startline before popping the clutch, then keeping revs up and slipping the clutch through the acceleration strip. In fact, it will be easier to maintain full engine speed with a heavy flywheel than with a light one, which explains why some drag guys prefer the heavy flywheel.
On the other hand, I personally HATE slipping the clutch at all, I even use the handbrake to hold the car on a hill rather than slip the clutch, since many years ago while lying on a wet driveway in a rainstorm putting a clutch in my wifes 67 fiat that I'd never do another clutch job (myself).
If your clutch fan makes a lot of noise, especially when accelerating, it is defective. I had one like that: it used to stick partway around. Go to the Pick n Pull on half-price day and get one for about $10. You just need a 10mm socket or combo wrench to undo the 4 screws, and maybe a long screwdriver or something to keep it from turning while breaking those screws loose.
Or you can get one from one of the guys here on the forum.
I have 4 rotarys, one since 1982, and never had a fan fail.
Technically, a lightened flywheel doesn't affect horsepower at all: it just assures that during acceleration more of the engine horsepower contributes to accelerating the mass of the car since less is required to rev up the rotational mass. This benefit disappears at constant speed, so top speed is unaffected, and dyno HP (which is usually read out at constant speed against a brake or an MG set) is also unaffected.
Of course, you can also obviate the benefit of lightened flywheel by revving the engine to best speed at the startline before popping the clutch, then keeping revs up and slipping the clutch through the acceleration strip. In fact, it will be easier to maintain full engine speed with a heavy flywheel than with a light one, which explains why some drag guys prefer the heavy flywheel.
On the other hand, I personally HATE slipping the clutch at all, I even use the handbrake to hold the car on a hill rather than slip the clutch, since many years ago while lying on a wet driveway in a rainstorm putting a clutch in my wifes 67 fiat that I'd never do another clutch job (myself).
01-27-08, 03:09 AM
#65
Even top fuel drag cars use a form of EFI called mechanical fuel injection.
Sorry if I got off on a tangent here. When I get the funds and a clutch fan ( I already have the clutch, I just need the fan itself) I will dyno my car with and without an E-fan, and test response, HP differences, rev-ability, and other factors and put this thread to rest.
Sources:
http://listing-index.ebay.com/cars/Subaru_Justy.html
http://au.answers.yahoo.com/answers2...0130045AAllJNJ
http://www.wikihow.com/Check-an-Alternator
http://www.supraforums.com/forum/showthread.php?t=4877
http://www.4x4wire.com/forums/showfl...7&Main=1058960
http://www.explorerforum.com/forums/...ad.php?t=75371
01-27-08, 08:27 AM
#66
I have a fan for you Stu, I'll find a box.
But since you've already admitted your prejudices, can we really trust your measurements of "test response, HP differences, rev-ability, and other factors"?
I'm worried that you might be vulnerable to what I call the "red leather interior syndrome", that is, if you've got one, you will think it's the best there is.
Seems like most of the folks posting here fall into that category (including me) which is why we can go on endlessly debating our favorite cooling systems. Which is fun, and even educational, sometimes.
But since you've already admitted your prejudices, can we really trust your measurements of "test response, HP differences, rev-ability, and other factors"?
I'm worried that you might be vulnerable to what I call the "red leather interior syndrome", that is, if you've got one, you will think it's the best there is.
Seems like most of the folks posting here fall into that category (including me) which is why we can go on endlessly debating our favorite cooling systems. Which is fun, and even educational, sometimes.
01-27-08, 11:50 AM
#69
I will add to my statement about the 20 amp spike when the fan(s) kick on by saying that you'd better run a 20 amp fuse.
The fan does freewheel sometimes, and takes less than 1 HP from the engine during this time. If you can stop it with your finger and hold it (or spin it backwards) it's not a parasitic drag on the engine. Try reving it during this time, and then try it again when the engine is hot and the clutch is running at full strength. Notice any difference in zinginess?
As I said before, I will use electric fans in certain projects where a clutch fan would be impractical. Otherwise there is nothing wrong with using a clutch fan - even on a modified/ported engine with a light flywheel - as long as the clutch fan is healthy.
This one time on my REPU, the clutch fan was locking up and drawing more power thjan it should. It would cause the belt to slip so I got a dual alt pulley. Didn't help so I tightened it as much as I could (not a good idea). Did stop the belt squeal. Then I took it out and installed an electric fan. The revability improved as did the acceleration a little. The cooling capacity did go down a bit. Then I replaced the electric fan with a healthy clutch fan and now it is the best of both worlds. Excellent cooling capacity, even with a supercharger, and it freewheels under certain conditions too. You can't argue with that.
The fan does freewheel sometimes, and takes less than 1 HP from the engine during this time. If you can stop it with your finger and hold it (or spin it backwards) it's not a parasitic drag on the engine. Try reving it during this time, and then try it again when the engine is hot and the clutch is running at full strength. Notice any difference in zinginess?
As I said before, I will use electric fans in certain projects where a clutch fan would be impractical. Otherwise there is nothing wrong with using a clutch fan - even on a modified/ported engine with a light flywheel - as long as the clutch fan is healthy.
This one time on my REPU, the clutch fan was locking up and drawing more power thjan it should. It would cause the belt to slip so I got a dual alt pulley. Didn't help so I tightened it as much as I could (not a good idea). Did stop the belt squeal. Then I took it out and installed an electric fan. The revability improved as did the acceleration a little. The cooling capacity did go down a bit. Then I replaced the electric fan with a healthy clutch fan and now it is the best of both worlds. Excellent cooling capacity, even with a supercharger, and it freewheels under certain conditions too. You can't argue with that.
01-27-08, 01:33 PM
#71
I'm worried that you might be vulnerable to what I call the "red leather interior syndrome", that is, if you've got one, you will think it's the best there is.
Seems like most of the folks posting here fall into that category (including me) which is why we can go on endlessly debating our favorite cooling systems. Which is fun, and even educational, sometimes.
Seems like most of the folks posting here fall into that category (including me) which is why we can go on endlessly debating our favorite cooling systems. Which is fun, and even educational, sometimes.
01-27-08, 06:00 PM
#72
Full Member
Join Date: Nov 2003
Location: San Diego, CA
Posts: 102
Likes: 0
Received 0 Likes
on
0 Posts
01-27-08, 06:12 PM
#73
Registered Offender
Join Date: Jul 2006
Location: Bishopville, SC
Posts: 689
Likes: 0
Received 0 Likes
on
0 Posts
There is already a thread on here somewhere where the guy showed an approximate 5-8 hp increase I think (dynoed with results posted) by replacing the clutch fan with an e-fan.
01-27-08, 06:38 PM
#74
Administrator
iTrader: (8)
Join Date: Nov 1998
Location: So. Arlington, TX!!!
Posts: 12,974
Likes: 0
Received 59 Likes
on
36 Posts
And it won't be until after Feb 2nd that we get the other thread concluded with the back-to-back same dyno day, same car, stock fan vs. Efan results...should be interesting..
01-27-08, 07:38 PM
#75
My 7 is my girlfriend.
iTrader: (5)
Join Date: Feb 2006
Location: London, Ontario, Canada
Posts: 3,162
Likes: 0
Received 1 Like
on
1 Post
Jeff's point behind this statement was how are you going to drive a mechanical fan facing the radiator when the majority of cars being churned out by the OEM's are front wheel drive. The engine is facing the wrong way to use a mecahnical fan. They could do it, but I don't think they would get much cooling out of pulling air off the fender:P The engine placement leaves them no choice but to use an e-fan.