Hello all,

I'm running a mechanical clutch fan and want to add an independent pusher fan(s) to my condenser to aid the AC vent temps in low speed/stopped conditions. I've read tons about this and the options are overwhelming. Since these won't be my primary cooling fans, would you still recommend a controller? My fitment allows for two, 12" electric pusher fans on the front of the condenser (side by side). I'm concerned about 1) amp draw when both fans kick on 2) what method to use to activate the fans (coolant temps, condenser temp, add a trinary switch on the high pressure side), and the fans unnecessarily being on at highway speeds, so having them turn off above 30 or 40 mph. I suppose a controller would solve these issues, but is it really necessary for just an aux fan?

 

Couple of ways you might skin this cat.
1. Just use a signal from the ecm to turn the fans? on as the temps go up in the engine.
2. Use a temp sensor from a Painless relay kit with bunge in the radiator.
Maybe a one 16" fan instead of two 12"?
Maybe one 16" fan on the inside mounted to the radiator pulling air thru the radiator and the ac condenser?

 

16" puller behind the radiator is what I use on my 97 van, PCM controlled.


Tight fit

Fan off in 105F

Fan on in 105F

Vent temps on High Blower on both front and rear units at idle.

 

sounds like the easiest way to control them would be with the ECM. Many here can help you with the tuning if you dont have a way to do it yourself.

that said, how well is your clutch fan shrouded? i recall you building some bits and bobs to get the rad and condenser pretty well sealed.

 

is that a clutch fan behind an e-fan?

 

It is, as he mentions in his first post.

 

G, how was i to know if by "16 inch puller ECM controlled", he was referring to the e fan or the clutch fan? If i am not mistaken, he has an electro-viscous clutch fan in one of his vehicles, which would be PCM controlled.

inquiring minds want to know

 

I was going by the pic that shows an e-fan right in front of the clutch fan. Plus he mentions it in the post.
The clutch fan is not externally controlled.

 

I'm going to recap what I think you're looking for.
1) Soft start for two small fans.
2) Turn them on when A/C is running
3) Turn them off when over a specific RPM

I can see a number of ways to do this, some better than others.
a) go out and buy an advanced controller from the aftermarket that can do this.
b) A Mazda/Mitsu module, a relay (maybe 2) and a RPM controlled switch
c) an arduino nano( with connection to A/C clutch and injector control wire) with Mazda/Mitsu module.

 

Duh!! I screwed up. Mixed up RPM and MPH. Ignore my post for now.

 

Ok, let's try this with a clear head.
I'm going to recap what I think you're looking for.
1) Soft start for two small fans.
2) Turn them on when A/C is running
3) Turn them off when over a specific MPH.

If it's just a condenser auxilliary cooling and you have 2 fans, a simple solution might be to just connect them in series and turned on by a relay connected the the compressor clutch. With both fans in series, inrush current should not be an issue and leaving them on at highway speed won't be that bad. Half speed for two 12" fans may provide ample A/C cooling, especially if your primary fan is helping.

if you're looking for a DIY solution with an Arduino and a Mitzu module, that is doable. The hard part of that is getting the MPH. You can get the MPH from the canbus (needs can bus module) or you can get it indirectly from the speed sensor (needs voltage conditioner) but both of those require alot of extra stuff. both ways are a pain and I wouldn't suggest it.

An easier way would be to get the RPM (right from an coil control signal (already 5V) and make a assumption that if the RPM has been non stop over let's say 1500 (tune this) for over 20 seconds, you can turn off the fans. That would include an arduino nano, a Mitsu/Mazda module and a few resistors. LMK if you want to go that way.

Another way might be to just ignore the MPH and drive the fans with a temperature sensor attached to the condensor. You could make the fans run harder the higher the temperature is. That would include an arduino nano, a temperature sensor, a Mitsu/Mazda module and a few resistors. LMK if you want to go that way. This is pretty much covered in the PWM fan thread in the forced induction topics.