Myth of the electric fan

[txarkitekt]

To everyone their own... I agree with Quik about the bigger trucks using a mechanical fan since their main purpose is for heavy duty applications. But with smaller trucks and cars, electric fans do help up some engine power. Any time you can take an accessory drive off your crank, you free up power--because your crank is not using that power to try and turn that pulley. Sure, it is minimal power gains, but you see most of it with throttle response. You also see a small gain in the mpg department as well. To me, it is a worth while mod--frees up power, better mpgs, not as noisy as the mechanical fan, more room under the engine bay, etc.
I still have the stock 105 amp alt. and it works perfectly. I have a decent setero in my truck along with electric fans...and with my smaller pulleys, I usually charge at about 15 volts on the voltmeter on my dash. If someone does efans and has a decent stereo on their truck, I would recommend doing a set of underdrive pulleys to help with more power and charging the alternator a little better...

[thunder550]

i was watching an off road race today with the baja trucks, you know what they all had? electric fans. while the article was written for a small foreign car that i dont know much about i dont think its applicable for our racing uses with trucks. I know some off roaders prefer the stock fan to electric when mudding, deep water, but most people here have on road racing trucks anyways.

Keep in mind that to protect the radiator, it is located in the back on those trucks where it's impossible to get a clutch fan to and it's not in the path of flowing air, so it needs fans to pull air through. There really is no other option in those cases besides e-fans.




I had e-fans, and I went back to a clutch fan. The wiring was a PITA for the e-fans. I tried 2 different controllers. First was a Nelson harness, and it kept eating relays. E-fans don't do any good when they have no power going to them. The voltage drop when the fans started up was horrendous too. I have a factory 145 amp alternator, and the voltage would drop from 13.9 to low 11's when the fans first started, then it would come back up to low 13's. I tried a DCControl soft start controller next. It worked better, but I was still unhappy with the low voltage once the fans were up to speed.

I had problems with my truck overheating while towing with the e-fans.

Under normal operation in normal weather I noticed absolutely no SOTP difference between e-fans and an unlocked clutch fan. Of course, in hot weather when the clutch fan would normally lock, it was nice to be rid of the drag from the clutch fan.

Overall, the costs of switching to e-fans for me were far greater than the benefits, so I'm back to a clutch fan for good. I don't have any complaints.

[GasGuzzler]

The gauge on mine doesn't move when the fans come on and I have the 145 as well. Wonder if you had another issue?

[567234ta]

it basically comes down to CFM, i dont really know what CFM the electric fans are or the clutch fan. if anyone does it would be good info to know.

[GMCwantsLS1]

I can turn off my electric fan at the track and make a pass. I can also run the fan with the engine off to cool down. Two things I can't do with a belt driven fan.

[thunder550]

The gauge on mine doesn't move when the fans come on and I have the 145 as well. Wonder if you had another issue?

I don't think so. I even tried putting in a second alternator and battery on a separate circuit to run JUST the e-fans and still got voltage drop. I tried two different batteries, 3 different alternators, 2 types of harnesses, and two sets of e-fans. My little foray into the world of e-fans was very expensive. I would have been better off taking that money and buying strippers and beer. Chalk it up to lessons learned. Other people may have had better luck than me, but for the way I use my truck, it was not worth it.

[567234ta]

I don't think so. I even tried putting in a second alternator and battery on a separate circuit to run JUST the e-fans and still got voltage drop. I tried two different batteries, 3 different alternators, 2 types of harnesses, and two sets of e-fans. My little foray into the world of e-fans was very expensive. I would have been better off taking that money and buying strippers and beer. Chalk it up to lessons learned. Other people may have had better luck than me, but for the way I use my truck, it was not worth it.

did they both come on at the same time? that would be quite a surge if that was the setup.

[GasGuzzler]

I see. Just wonder if there was a ground issue or something. Could have just been chance I guess. Expensive lesson indeed. Mine work fine, I'm very pleased, and I even question the $$$ I spent.

[thunder550]

did they both come on at the same time? that would be quite a surge if that was the setup.

The Nelson harness works as follows:

Temp signal enabled, a/c off: Both fans on low
Temp signal enabled, a/c on: Both fans on high
Temp signal not enabled, a/c on: One fan on high, one off
Temp signal not enabled, a/c off: Both fans off

The DC Control unit was a variable speed controller. It had an a/c trigger wire that turned both fans on 50%.

Any time either or both of the fans went from off to high or low to high I would get a drop.

I see. Just wonder if there was a ground issue or something. Could have just been chance I guess. Expensive lesson indeed. Mine work fine, I'm very pleased, and I even question the $$$ I spent.

I did the big 3 a long time ago with 0 gauge wire. I think it's safe to say that I don't have any wiring issues. I was very thorough with all of it and I spent many hours tweaking and rewiring stuff to try to make it work the way I thought it was supposed to.

[Frenchy]

Mine came with them, so I can't really make a comparison but honestly if there good enough for the GM engineers....