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Looking for some efans for the sierra. Just needing more room in front of the engine. Came across this.. its aimed toward rx-7s but thought it was interesting.
Its mostly cons of efans over stock. Give it a read, not too long. And what are some benefits, as I have non for now, except room.
The Myth Of The Electric Fan
It appears that what he is saying here is that no real power is freed up from using efans. Maybe I am just really confused, but I have seen people post and give examples even videos of gains on the dyno of 5-10 rwhp. Can some one clarify for me?
Ill tell you what. Next time I get dynoed, Ill do My testing and runs and then ill put the clutch fan back on and see exactly what this means for us.Quote:
Originally Posted by kerrige
i really disagree with that, when i removed the stock fan from my 5.7L L31 i noticed a faster throttle response and the electric fans provided plenty of cooling. I really prefer the electric fans for many reasons.Quote:
There you have it. For the most part, electric fans are not recommended as an upgrade unless you have a very specific reason to do so. They provide inferior cooling to the stock fan
i have an override switch that turns on my ac fan so i can have awesome cooling at idle. this is good for tranny cooling, stuck in traffic, stuck in mud, snow or whatever. If you have a tranny cooler and you are stuck you are sitting there spinning the wheels heating up the tranny but the cooling is only for the engine temp if you have a stock fan.
i would never go back to a stock unit after seeing the difference and advantages to electric fans. and his conversion or hp to elec couldnt be more flawed, what about the battery? thats what they are there for. while you are on the highway and the electric fans arent even needed the alt charges the battery(s) just fine.
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.
thanks jeff I am not gonna lie that is way beyond what I thought anyone would do. Way to step up. I expected maybe just people to voice their own opinions. It will be awesome to see someone settle that debate in one shot. Oh and how long does that actually take to do....aka change them out and back again?
Seems like most if not all racing apps use efans to cool.
It makes sense to me giving you more power and better throttle response. Its just less the engines got to turn, even when the fan clutch isn't engaged.
I also don't see how he is saying its overstressing an alt, since.. tell me if im wrong.. most electronics connect to the battery, then the alt charges the battery. So the fan adds no, or very little extra pull on the alt. So I can kind of see where you get better response and power with efans over using the stock fan
Guess the same argument for epumps, less the engine has to turn. Just more the battery gets used thus the more the alt needs power from the engine. But still less than what the pump or fan needs directly from the engine
Now that would be awesome actually testing to see what you gain from efansQuote:
Originally Posted by ff_jeff
Never really noticed any performance gains with mine on the Denali 'cause it already has OK power and is a huge pig. Noticed a little more power on the 4.3L Blazer but it's small and weak.
It took about 30mins to install my efan. That included wires and all. AS for putting the stock one back on... it just threads back on the pully, and 2 bolts with abut 5-6 plastic push pins. It shouldnt take more than like 10-15 mins to revert back and forth, since the hard stuff is allready done.Quote:
Originally Posted by kerrige
After I get cam installed I will make an appointment with Allen at Nelson performance to get a dyno tune. Im sure he would not mind too much.Quote:
Originally Posted by mnc2fan
Actually, the fans DO put extra strain on the alternator because it has to work harder to keep the battery charged. But that is really irrelevant anyway because your alternator isn't going to crash from running efans when people run 1000 watt stereos on stock alternators. I've done a lot of study on the charging systems since getting into car audio. In my 69 I run a 240 amp (180 at idle), my regular battery, and a special audio battery (Batcap 2000).
The main thing is, if your voltage isn't dropping to extremes and the headlights don't dim, you're safe.
I think the dodge 3500's come with a clutch fan and electric fans to keep the cummins cooled.
I like the Efans, more room to work.
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...
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.Quote:
Originally Posted by 567234ta
http://www.knfilters.com/images/press/jefferies2s.jpg
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.
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?
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.
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.
Quote:
Originally Posted by GasGuzzler
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.Quote:
Originally Posted by thunder550
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.
The Nelson harness works as follows:Quote:
Originally Posted by 567234ta
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 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.Quote:
Originally Posted by GasGuzzler
Mine came with them, so I can't really make a comparison but honestly if there good enough for the GM engineers....
GM controls them differently through the PCM to so it doesn't load up the electrical system the same way that retrofitting them on an older truck does. Also, I believe that the HD trucks still come with a clutch fan for higher cooling capacity.
Not mine. Under this scenario, mine has RH on high and LH on low. The only time mine is "supposed" to do hi/hi is in an overheat condition and it hasn't done that. No wonder you had so much draw.Quote:
Originally Posted by thunder550
HD's have a different radiator and stuff too....and don't come with 145 alt's usually. BTW, I still see your point.
I dunno how yours are wired up, but this is how the Nelson harness does it. Yours could very well be different. I'm just speaking about my own personal experiences.Quote:
Originally Posted by GasGuzzler
HD's (any of the 6.0L trucks) have the same 34" radiator that I put in my truck. I was running factory 05+ fans too. I dunno. Maybe I just had some bad luck or something, there are many people out there that seem to have good luck with e-fans, but I think I probably push my truck harder in a hotter environment than most people do.Quote:
Originally Posted by GasGuzzler
lol this is funny ok class basic math here. Less drag from clutch fan equals gain in power and as far as cooling goes my hpm fans could cool a catapiller deisel lol
OK what we need to understand from a towing stand point is e-fans have basically 2 speeds. High and low clutch vans are varible depending on engine RPM and can create more or less CFM's depending on the need for cooling. Thus why they use them on heavy duty apps when towing. E-fans have one max CFM rating and most are not enough for towing. The newer Cummins may have e-fans to help with getting all the air over the 5097986987 different coolers and A/C stuff.
I had e-fans on my 1500 HD turbo truck and they cooled just fine and never any problems but throw 8000# behind it and its a different ball game.
E-fans are great for elminating the recipricating force of the crank. Simple math...less mass to move = more useable power.
The alt provides the electrical system with power and maintains a charge on the batt, when the amperage is exceded then the electrical system pulls power from the batt till the alt can catch back up. If you draw more power than the alt and batt can give is when you start frying alt's. Been there done that....stupid 4000 watt stereo systems pfft.
How many newer high HP cars have clutch fans? How many have e-fans?
E-fans for racing, clutch fan for towing. :)
Well said Aaron.
Quote:
Originally Posted by thunder550
I have the Nelson harness and it operates like I listed. Maybe your Nelson harness was faulty (please don't throw stones)?
LOL
The 34" HD radiator is almost twice as thick as the 34" Denali/Escalade radiator. Maybe you did have the HD and the fans weren't as good pulling through the thicker core?
Quote:
Originally Posted by GasGuzzler
Hmmm...I wonder if he made a change to the fan harness? Every one that I saw/heard of when I was doing the e-fans worked the way I listed.
I was not aware that there were differences between the two 34" radiators. Interesting.