Topic: How to install E-Fans

[oHIobellboy]

I went over to Ohio Generators today after work and talked with the guys there. I was considering one of their 8600-200 alternators ($500) but they load tested my Avy with everything running (a/c,horn compressor, hids, rear defroster and even running my slow drivers window up and down) and only pulled 80 amps and that's with a battery that didn't have a really good charge on it. They're gonna put together a 140 amp alt for less than 1/2 that for me.

[MS03 2500]

Bud GM has a 145 amp Alt, it's part of the FE3 snow plow package. All you have to do is add the right belt.

[oHIobellboy]

Bud GM has a 145 amp Alt, it's part of the FE3 snow plow package. All you have to do is add the right belt.

I'm getting this one at a good price and keeping the same belt. They also are putting a smaller pulley on it so it charges better at idle

[MS03 2500]

OK 

I just hope you don't have a Optima battery

[oHIobellboy]

OK 

I just hope you don't have a Optima battery

No Optima, looks like an  Autozone special.  What's up with the Optima that you say that?

[FlaBouy]

I have a spare 180A from AlterStart laying on my bench. Be careful with aftermarket alternators because they typically require a different size belt. My Vortech blower came with a spare belt for using with aftermarket alternators... I think I recall them being 1" longer...

E-fans are easy if you have HPT. GM also sells an e-fan harness that is factory and integrates with the underhood fuse box and works with the 2005 and up dual fans. Be careful when selecting the fans, because all fans are not equal load wise and depending on what you buy, you can melt the relays in the fan harness... ask Damon about this.... 

I did some load testing on the large fan sets for the 34" radiators and saw nearly 80A starting current and then they settled down into a 35-40A range on high with both fans kicking.. I have some test data on that somewhere. If I have time today I will dig up the link over on Allen's site where we did the testing and posted the part number of the factory GM harness. It also has some good info in there about starting/running profiles and the load test data. It gets into the relay ratings etc... I also designed a custom harness for those that want to build their own. The drawing is over there with part numbers for all the fusing and relays. You can also get a copy of all this from Damon, since I designed it for his truck when he was melting relays....

If I had access, I would link the thread over at the punk site...... 


EDIT: added pics of GM harness

[FlaBouy]

Quote from my posting on Allen's site:

Data:

Both Fans on High Start up: 87A 
FLA (Running Amp): 38A

Both Fans Low Start up: 29A
FLA (Running Amp): 9A

One Fan on Hi Start up: 55A
FLA (Running Amp): 20A

The smaller LS1 style fans like I have that fit the 27" radiator work fine with the Nelson harness. The harness is rated at 30A with the smaller fans...... I have a couple harness designs for the larger fans and we are seeing the need to thermally protect the harness in excess of 40A with the large fanset..... The isues with Pin 42 and Pin 33 are almost a mute point in most cases since there are several means to trigger the fanset with a combination of rocker/toggle switches, thermal switches driving off ECT, or just using the stock triggers that GM has programmed into the PCM.... Nice find on the 05 harness part number though... We have just purchased one to reverse engineer so our truck club members without electrical wiring experience can buy an "off the shelf" alternative to wiring ther own.....

[FlaBouy]

Here is the link to our discussions over on PT.net... MY reply #30 has the basic info, including the GM part number for the factory E-Fan Harness on the 05's that fits all our trucks...

http://www.performancetrucks.net/forums/showthread.php?t=330567&highlight=2005+PCM


"GM Parts direct has an 05 harness Part number 15216055."

[FlaBouy]

Sorry about the double, triple, and quad-druple postings.... But I had a member PM me for info on E-Fans for our truck...

Just bumped that old 2006 part number against GM Parts direct. Seems it has been superceded to a 15912581 part number....

That harness comes complete with fuses and relays for the dual fans.

[Main One]

OBB, I have put my stock alternator back on, and put on a larger pulley so that there is less load at speed, although as you have noted,  at the expense of charging power at idle.  I figured that since because of my cam I have bumped up my idle speed anyway some, it was less of an issue for me.

Through HPTuners, I not only can up my idle speed, but I have it also go higher at higher coolant temps (where the fans will kick in at low speed) and even higher at higher coolant temps when the AC compressor is on (when the fans kick in at high speed).  I set this programming up during the heat of the summer, and after having now run this through some good temp extremes, I'm thinking I can back off how much my idle increases at the higher coolant temps.