JALVORD_2003_68

I was wondering what is better a Mechincal fan(for the radiator) or a electric fan?

Mech.

Pros-
doesn't require any adjustment
no new wiring
cheap to replace

Con-
doesn't cool very well @ low RPMs.
You can't turn it on manaully

Elec.

Pros-
cool the same @ ALL rpms
Ability to manually turn it on
you can adjust the temp. when it kicks on

cons-
more expensive
wiring required
adjustment to dick around with

What do you think?

stinkfist

I prefer electric fans. The wiring is so easy that a novice should have no problem with it. Electric fans take up less space and free up a small amount of HP. I think they also look cleaner in the engine bay.

A mechanical fan is arguably more reliable. I can't think of any other reason to go with a mechanical.

MIke

mar3

iTrader: (8)

The electric fan...you're losing 10HP easy from driving that clutch mechanical fan...

85RX7GS

iTrader: (1)

Where can I buy a Black Magic fan?

SilverRocket

summit racing, or go on flex-a-lite's website to find a local dealer

Directfreak

iTrader: (2)

HERE

SilverRocket

No, it's not 10hp. I noticed a small acceleration advantage in 1st and 2nd gears with my Black Magic, nothing to justify spending the money if your fan clutch isn't already bad. If you don't need a new fan clutch anyways, spend your money on something more worthwhile. Then again, if you're looking for that final piece to complete your setup and you've already got every other bolt on, go for it.

mar3

iTrader: (8)

Clutch fan in 5.0 Mustang on dyno that was replaced by electric fan and then run on dyno saw a 45 HP gain. The mechanical fan is that bad even with the hydro-clutch. Sure we won't gain 45 HP but that was roughly a 10% pickup on that Moostang. 10% of 100 HP=10 HP...now you know where I pulled that number...

theNeanderthol

iTrader: (1)

this might sound wierd but I would think that you would lose HP with an electric fan. Of course dyno tests prove me wrong. I was just wondering if anyone could explain it. Here is my reasoning. A mechanical fan takes mechanical energy from the motor. Probably 30-40% effecient i guess. An electric fan has to turn it into electric energy in the alternator first, 30% efficient, then bach into mechanical energy in the fans motor, 30% efficient. When somthing requires electricity from the alternator, it puts more drag on the engine. Why do we see gains wth an electric fan?

Aico

Because you have a pre-charged battery

Project84

This is not true. An alternator does not become more difficult to turn when it creates more power. My Ford Explorer does not slow down when I turn on the headlights. (yes, the battery can power the lights, but the alternator constantly charges the battery so you have juice to start the car next time.) Your car doesn't slow down when you turn the music up louder. You don't feel that same kick in the alternator as when you turn on the A/C. The A/C uses a clutch which becomes more resistance that the engine has to work against. The alternator doesn't engage or disengage any of the coil windings or electrical parts. It spins and makes AC (alternating current). There are a set of diodes, which are like check valves for electricity, that change some of the power to DC (direct current) before it gets to your battery.

An electric fan does eliminate one item that the engine has to turn, thereby freeing up Hp and allowing the engine to run more efficient. Also, electric fans look nicer (IMO) and cool better at lower engine speeds.

RXcetera

10hp! LOL, its a fan! It's not very hard to turn in the first place and it only has to be spun to 2500rpm. Try running your car with and without the fan... you wont notice ANY difference (exept on your temp gauge).

WackyRotary

Exactly. I took mine off in cooler weather (below 50F) to compare power. NO desernable difference!!!! And if its not desernable, the net gain is less then 2hp. I think electric fans are nice looking, but the cost/per/hp gain is VERY questionable at best.

If you had a clutchless fan which matches rpm with every engine speed, YES, then you would get noticable increases at high rpm. But with a PROPERILY working clutch fan, it will work just fine without problems.. I know if your clutch fan is working improperily, the belt will start squealing by 4000rpm! Thats a sign its bad.

mperformance

you can't say it doesn't take any power to turn. It actually takes power when the fan clutch is engaged at normal or hot operating temperatures. When it's cold the mechanical fan barely uses any power.

WackyRotary

Well mperformance, you can take comfort in knowing that if your reving your engine past 4000rpm, it will not be spining the fan that fast unless its broken. If it is, the belts WILL squeal badly! Ask how I know!

On a hot day it still won't match engine rpm past 3000rpm, if it did, again, it would squeal the belts! Those pulleys can only hold maybe 4-5hp transfer before they slip. Its a good thing too, because that is a strain on the water pumps bearings.

Also, your right, when its hot, it will drag more energy as needed to cool the engine. But the engine would also drain more power when powering a electric fan. They are usually in the 30amp range. Again, if it is squealing the belts, it means the fan clutch is broken or malfunctioning. They will never turn more then 3000rpm if working correct which is no more then 2 or 3hp.

SilverRocket

You can't just invent a number using an arbitrary calculation. I have an electric fan, and I can tell you it's a very small gain. I have witnessed people pulling their fans off completely to experiment, and trust me they weren't 10hp faster lol.

The only reason to get an e-fan is if your stock fan clutch is dead, because the replacements are just as expensive. It is also nice than you can control it with a switch, and run it with the engine off if you feel like it (not that that's much good; if you want to cool your car it's best to leave it on with the water flowing through it.) Anyways, it's not some big mod that makes a big difference.

mar3

iTrader: (8)

Unless you guys got dyno numbers to prove what you're saying, you might as well be saying nothing. Your butt opinion is worthless unless it can be backed up by hard data. The Mustang dyno test was hard data. The drag imparted on the fan blades of a big, ugly, horse-power sucking mechanical fan is substantial. Percentages do work. Arbitrary is just guessing and that's not what I did. I had a factual basis to my line of reasoning. Everyone else is speculating. Do you have a G-Tech, at least? Take it out and find out or stop putting ill-informed seat-of-the-pants hunches out there like it's a fact. I've got time proven wisdom of Hot-Rodders before me and a dyno article to back up my speculation. The rest of you have nothing. It does cost horsepower, but it doesn't create horsepower by ditching the mech fan. You just get rid of another huge, gigantic, life-sucking, rpm-killing piece of mechanical crap you're engine is better of without...

..ps. Hell yea, I DO have a G-Tech...

SilverRocket

Saying nothing? Okay Mar3, go ahead and argue with the experience of numerous people who have done this mod and know what they're talking about. Do you even have an electric fan??

Look, I spent $400 on that damn Black Magic, don't you think I'd like to say it made a big difference? Sure, but you know what, the fact of the matter is it didn't.

If it pleases you, I can tell you that I performed quartermile runs before and after my e-fan install, and there was hardly any difference.

Look man, I have put 70,000 kms on my car over 6 years, and have performed several power-gaining mods in that time. I've gone from 100hp to 150. I know what a 10hp gain feels like, and I know what a 1-2hp gain feels like. It feels like not much at all. An electric fan does not give you a significant power gain, I don't know how to make it more clear.

WackyRotary

Your crediblity goes WAy down when you show a before and after comparsion of a Mustang instead of a 1st gen RX-7. How do you know the mustang didn't have a direct fan with no clutching? Do you know what year they were testing? Older ones likely have direct fans. Also, how do you know the test conditions so well for the before/after results? 45hp is a big bit of fudging, no doubt. You know what fudging is don't you? Relative air desity correction for SAE conditions, rounding off, etc, etc.

Dude, I don't intend a flame war, but JEEZ, anyone who has a properily working clutch fan can compare the difference with it oFF! The net gain is if anything, so little that the cost of getting a electric fan is a visual difference mainly. I have had mine off and the difference in my test was no better then with it on! Thats why if my fan clutch went bad, I wouldn't buy a electric fan unless it was used and less then $50, I'd go to a junkyard and pick up a used fan clutch for $10.

mar3

iTrader: (8)

Joy...I'll start at the top...I'll also skip who said what and just address the statement...

Again, they did the mods but were they on the dyno before and after within a span of a week? If not, then their opinion is also worthless. The butt dyno is only good for bench racing. It has no place in a real tech conversation. Ask Paul.

Of course I do...that horrible, mechanical piece of blood-sucking torque-killing junk of a clutch fan wasn't going to stay on my rex for long. It was a Derale 1900 cfm. Ask Jose Reyes what he thinks of these gems. And all for $120 bucks.

Please! We're not here to please me! We're here to ascertain the truth! Even pro racers without a Dedenbear to help will concede times can't be used realistically to gauge HP improvements. Top end speed is relatively consistent enough to judge, however, but times are not because of the human factor. Reaction time, shifting the same rpm, etc...a dyno factors all of that and spits out useful info.

Again, a butt dyno doesn't count. Post the dyno slip that shows you have 150 HP. I'll bet you don't have one. To paraphrase an earlier shot at me.


My credibility? I'm one of the few that has done the dyno before-and-after thing. Do a search or ask V8kilr. As for my source, it was from an article done last year in Car Craft or Hot Rod. Ask pele for the details. He read it, too. I could probably find it again if it was in Car Craft, but I recycle all of the Hot Rod mags. They went from stock to flex fan 1 to flex fan 2 to electric fan. They did it all in one day on a dyno with a 5.0 pulled from their Moostang mule car. All data was corrected, so the numbers could be compared apples-to-apples. The difference from the stock set-up to the electric was a whopping 45 HP. More than even they expected. Fudging is what you do when you declare 150 HP just by the size of the $$ you spent and driving around. Gotta get dyno.

Let's see their dyno slips...

Please add "IMO" to validate this statement...

So you did go to a dyno...let's see the slips...anything else was not scientific and good only for bench-racers....

And, undoubtedly, you're running a Carter fuel pump,as well...

Look, fellas, just preface you're comments with "IMO" and I'm outta ammo. I've got scientific backing, you don't. That's the reality of the situation. You wanna prove me wrong, spend the $75 to get on a chassis dyno and post the results. I'll be the first to eat a big helping plate of crow if you prove me wrong. Gotta get back to work...man, I feel all...sterling and stuff...

jeremy

iTrader: (1)

mars3 put the smack down, imaho. i'd say it will affect hp but i'd like to see a 1st gen stock to elec, back to back.

mar3

iTrader: (8)

V8kilr would be more than happy to help you out again...nothin' to it but for to do it, maihn!! This nonsense graveyard shift I'm on has got me light-headed and vicious...my old UPS mean streak is starting to come to the surface again...

jeremy

iTrader: (1)

???????????/ not following the remark about dave man. give me a few more drinks and i'll come back tp it.

mar3

iTrader: (8)

I just followed that crazy series of threads when he went to your casa to get your lump running...I figure he could probably pool resources with you to try the electric fan dyno test session. That, and he has access to aftermarket stuff on the cheap to get stuff like a flex fan to try to replicate the CC/Hot Rod test session. Why not be the guys that do it instead of waiting for me? Y'all oughtta know by now if I hit Alamo Autosports, I'll fudge the crap out of that session and get a guaranteed 25 HP gain any way I can!!

Directfreak

iTrader: (2)

At least he's honest!