Fan speed and noise

[AA-ron]

Hello everyone,
This past fall my alternator failed (parasitic draw). I replaced it, and the first thing I noticed is that the new one produces higher voltage at idle. My old alternator at idle showed just 12.8 volts-- which was sufficient. However, my new alternator is showing 14 volts at idle. The problem with this higher voltage is that my fan speed is running much higher and is considerably noisier. With the old alternator you could hear the fan at idle, but it wasn't obnoxious. Now at 14 volts its very obnoxious. I have a relatively quiet exhaust, which makes it even worse. I did test the voltage at higher RPM's and it never exceeds 14.5, so the alternator is working correctly. Also, just as a note, the pulley diameter is the same, so it's spinning at the same rate as my old one.
Have others had this problem? I'm on the hunt for solutions before the summertime driving season!

[Mike.Bray]

The FFR supplied fan sounds like a jet engine for sure, you can definitely hear it over the exhaust at idle. What's sad is it doesn't move very much air. Change it to a Flex-A-Lite 105390, much quieter and moves about double the amount of air.

[GoDadGo]

Change it to a Flex-A-Lite 105390, much quieter and moves about double the amount of air.

Hey Mikeee,

Are the mounting points in the same location as the stock fan supplied by Factory-5?
While I don't have an issue with the airflow, I'd like to have a quieter fan if possible.
I'd keep the old unit as a backup fan, but both need to use the same mounting holes.

Steve

PS: I've got a complete set of switches, an extra set of headers, a spare flywheel and an extra set of wheels and tires.

[rich grsc]

I can answer that, no you will need to drill new mount holes. It's a simple thing to do, just pulled the shroud, drilled and installed new rivnuts.

[GoDadGo]

I can answer that, no you will need to drill new mount holes. It's a simple thing to do, just pulled the shroud, drilled and installed new rivnuts.

Thanks Mr. Rich!

[Mike.Bray]

I'm glad Mr. Rich answered as I don't know. I powered up the FFR fan on the bench and my neighbor came over wanting to know if I was putting a jet engine in my car. So I never installed it.

[Mat1asBEV&ICE]

I just switched from the FFR supplied radiator fan to the Flex-a-lite. I have the Breeze shroud. It was easy to do and as Rich said just drill four new holes on the shroud. Plenty of room. It's also lighter and the electric motor is noticeably shorter/takes up less space.

[BRRT]

How does the current draw on the Flex-A-Lite compare to the FFR fan?

[topherchrisb]

I went a little different direction. I got a fan controller from autocoolguy. I have a coyote and think it sheds heat a little more efficiently already but with the controller the fan maybe gets to 10% speed when parked for a while right now. It is winter though(tested at about 50f) so I'm sure it'll be a much different story in mid summer. I was getting some audible buzzing from the controller that is only noticeable with the engine off but I'm running the FFR pipes. It runs for a minute or two after I shut the car down. The buzzing was much more annoying before I realized the buzz was being amplified in my speakers. A ground loop isolater inline before the speaker amp took all the speaker noise away and I'm much happier now. It has a few trigger methods... the analog sensor for ramping speed, an AC trigger line that comes on at a dialed in amount, and an fail safe that kicks on full bore. But they are pricey.

[FLPBFoot]

How does the current draw on the Flex-A-Lite compare to the FFR fan?

Flex-a-lite draws 18.5 amps. I don't know about the FFR one.

[Nigel Allen]

Hi AA ron,

if you put a diode in series with your power supply to the fan, the voltage will drop by about 0.7V volts. Two diodes in series and you have a 1.4 volt.

For ease of wiring, you could put a 30amp bridge rectifier inline with the supply to the fan. Something like this:

https://au.rs-online.com/web/p/bridge-rectifiers/6296320?cm_mmc=AU-PLA-DS3A-_-google-_-PLA_AU_Pmax_LocalStock_0923-_-20564329606-_--_-&matchtype=&&gad_source=1&gclid=Cj0KCQiA8fW9BhC8ARIsACwHqYqxHlB6Ln0UeDHHwRgJ ToI--A8RgoCu7RJqryDQUzyNEJeVjwPVAu4aAkKqEALw_wcB&gclsrc=aw.ds

Positive and negative in from the fan supply, positive and negative out to the fan motor. One screw, (hole through centre) to mount it somewhere.

Let me know if you need any further info.

Cheers,

Nige