Electric Fans, fact or fiction?

[YBNORML]

I just purchesd a 1999 crewcab shortbox. The P.O. has changed from the stock clutchfan to an aftermarket electric unit. He swears that it helps improve gas mileage.

I do not have much experience with this mod. Has anyone here? If so, what was the result?

I know your all pic w$%^es, I do not pick the truck up till midweek. I will post pics as soon as I get it.

[piecesparts]

By itself, it may not help a whole lot in the MPGs, but the heat up rate in the winter is better and the engine will run smoother without the fan being on the waterpump. I did the change overon my 91 and also did the route with the MSD multi-spark kit and larger spark plug wires. That along with the headers, I was putting down a steady 20 MPG daily with the truck. I liked my truck with electric fans and it seemed to cool better with the fan setup that I had.

[tommie]

I have thought a lot about an electric fan set up.... curious to hear about others experience with fuel mileage....

[YBNORML]

I downloaded these from the for sale ad. They are not the greatest, truck looks better in person.

[piecesparts]

I just told you about my old daily driver and that truck was getting 20 MPG with 300,000 + miles on it. I also have my 84 GMC that has an electric dual fan setup in it with a 383 stroker engine. Works great and colls great. Just make sure that you use heavy duty relays to ensure that they do not fail in hot weather. The stroker setup gets 15 MPG, with a 3.73 gear ration and a 700 R4 tranny. We did the whole Hot Rod Power Tour with it in 2010, no issues to really speak of.

I use the SPAL dual 12" fan setup that is listed under "Be Cool" fans in the Summit Racing website. I also run a fan controller from SPAL to allow for one fan to run and then if really ot the second comes on.

[YBNORML]

Originally Posted by piecesparts

I just told you about my old daily driver and that truck was getting 20 MPG with 300,000 + miles on it. I also have my 84 GMC that has an electric dual fan setup in it with a 383 stroker engine. Works great and colls great. Just make sure that you use heavy duty relays to ensure that they do not fail in hot weather. The stroker setup gets 15 MPG, with a 3.73 gear ration and a 700 R4 tranny. We did the whole Hot Rod Power Tour with it in 2010, no issues to really speak of.

I use the SPAL dual 12" fan setup that is listed under "Be Cool" fans in the Summit Racing website. I also run a fan controller from SPAL to allow for one fan to run and then if really ot the second comes on.

Nice setup, very clean. The setup in this truck is nowhere near as clean. I'll definately go through mine when I pick the truck up.
Thanks,
Jason

[atomichoe094]

heres mine. I love them, there the flexalites 280 model. Very quiet, got them cheap which was awwesome!, look nice, way more room to work when changing stuff, on and off manual switch as well as auto, the cowl hood really helps getting the heat out at stop lights and such..

[bpeters5814]

Not trying to thread jack, but I've got a question. The '88 K3500 I just picked up has a 454 in it. It currently has no fan, and I'm trying to decide what to do. Should I just get a stock fan that mounts to the water pump? Or would I be better off with an electric fan set up? If so, how much would it cost approximately, and how difficult to install? When Grandpa owned this K3500 when I was a kid, I seem to remember it running hot, but maybe I'm making that up. Will the stock fan keep the 454 cool in the spring/summer when I'm pulling trailers?

[72lb4x4]

To the OP's question, I'd say from a theoretical point of view, electric fans would be less efficient.

Why? Because a mechanical fan is converting the engine's rotational movement to air movement. Converting the engine's rotational movement to electricity via the alternator, then the electricity to rotational movement in a motor, and finally to air movement has to be less efficient.

Electric motors are somewhere around 65% efficient I'd guess, and I suppose the alternator can't be any more efficient.

[orngsikL]

taking the fan (clutch) off puts less strain on the engine. they will help.

[YBNORML]

Usually when I have a truck that I use for everyday use, I try and keep the running gear as close to the way the factory built it. I do this for ease of roadside repair and dependability.

Do newer trucks run factory Electric fans for cooling? I haven't even looked under the hood of a newer truck so I don't know.

If an electric fan truly increases mileage and horsepower I will leave it as is. If it doesn't than it is not worth having it on the truck.

[jb1016]

Everything I have heard about E-fans has been positive. One less thing for the engine to spin equals more spin to the tires for less gas.

There's a really good DIY thread around here somewhere...by MemphisMatt, I think??
Edit: Here it is.

[piecesparts]

Originally Posted by YBNORML

Usually when I have a truck that I use for everyday use, I try and keep the running gear as close to the way the factory built it. I do this for ease of roadside repair and dependability.

Do newer trucks run factory Electric fans for cooling? I haven't even looked under the hood of a newer truck so I don't know.

If an electric fan truly increases mileage and horsepower I will leave it as is. If it doesn't than it is not worth having it on the truck.

Yes, the new trucks have electric fans. My 2011 GMC uses electric and it is very efficient. The fans cool when needed and at stops, the fans still run to remove heat that the mechanical fan will slow down to not remove as effectively. I run a variable speed fan controller on my fans and it cycles the fans on as needed and shuts them down when not needed.

The removal of the mechanical fan removes parasitic drag and allows the engine to develop the 10 more HP that can be used elsewhere. Now it does require a good charging system and a good fan switch system. I ran my 91 truck for four years with the electric fans I live in Kansas (100+ degrees in the summer and 10 degrees in the winter) I had no issue with the electric fans and the truck DID warm up better in the winter than with the mechanical fan. It also stayed cool and the A/C worked fine in the summer.

My play truck has had it's electric fans since 2000 and it works well. I orginally had it wired to run both fans when they came on, but since then I changed it over to the fan relay to allow cycling them on, one at a time or when needed. I took this truck on the Hot Rod Power Tour 2010 from Iowa to Alabama and it was hot and sticky in the South. No cooling issues, and I like being able to use every ounce of power at the ground.

[atomichoe094]

ive never heard anything negative about the elec fans besides if one goes.. hence why you have 2 fans and youll be golden.
on the stock alternator on my 95 tahoe with no issues what so ever. also run HIDs and a decent sound system.

Do a big 3 upgrade and youll be set

[BigBlocksRule]

I'm going to guess it'll be a wash.
Clutch fans steal a bit of power from the crankshaft to make 'em turn.
An electric fan will draw more current, making the alternator work harder which makes it harder to turn. Alternators don't make electricity for free, it costs horsepower to turn one. The higher the load, the more work it takes to turn 'em.
bpeter, check the radiator, make sure it's 2" thick and clean, inside and out. I've never had a 454 that ran hot, always used factory water pump and good radiator.

[atomichoe094]

buy a High Output alternator and do the Big3. The big3 itself helps out A LOT

[piecesparts]

Originally Posted by BigBlocksRule

I'm going to guess it'll be a wash.
Clutch fans steal a bit of power from the crankshaft to make 'em turn.
An electric fan will draw more current, making the alternator work harder which makes it harder to turn. Alternators don't make electricity for free, it costs horsepower to turn one. The higher the load, the more work it takes to turn 'em.
bpeter, check the radiator, make sure it's 2" thick and clean, inside and out. I've never had a 454 that ran hot, always used factory water pump and good radiator.

My experience is that it is not a wash. The alternator does carry more load, but it does not put the resistance on the engine that the 14" to 19" fan does. The fan pulls a lot of air and that calculates to a heavy load and when the air is cold and dense, the load increases, even with a clutch unit on the fan. You also have to look at the other advantages that are given by going electric, such as continued fan speed and cooling when the vehicle is stopped and a faster warm up in the winter. Every one for their taste.

[89chevsj]

not to thread jack but does anyone have a write up on the swap?

[atomichoe094]

i do on a different forum. not sure if im allowed to bring it over.. but its for the flexalites

[Dunenutt]

Never noticed a mileage increase, but the a/c will blow cold at a stoplight.