Rx8 fans in RX7 FD
 

Not too long ago, my fans stopped working. The fans just seized. Looked around for replacement, and they were too expensive going oem FD. And I did not want to go aftermarket electric because they wouldn't cool as good as stock. So, I bought myself rx8 fans, the whole setup with the shroud for $50 out of a 2009 rx8, and simply swapped them instead of the rx7 fans. All you have to do is take them out of the rx8 shroud and drop them into the rx7 shroud and wire them up. The colors are the same, but if anyone needs, I have wrote out what fan wires correspond with the harness wires.

Very nice! Write up would be appreciated.

Do they cool the same or better than FD fans?

They cool better then the stock white fd fans. These fans are actually the same fans (?) as the 99 spec fd's come with. You can get rx8 fans dirt cheap.

that is correct, the 99+ FD fan blades are the same as the Rx8, and a couple of other Mazda's

Write up please

That is the discovery of the day for me , really appreciated information, nice found.

interesting discovery!!
write up more about it thanks!!

Great news, thanks! And what more is there to write up?! This could not be easier!

I got an earlier RX8 fan setup, and it only had two wires, not the four like the RX7.

How did you do the wiring ? I did the same color, and mine spun backwards, then the 60-amp fuse blew!

:-( neil

hmmm interesting

i'm sure it can be done , you have to look at an RX8 and see what each color does . which ones are positive or neg , Than you need to study how the FD system works and than its simple you just rewire it .

its VERY simple

Attached are two cooling fan schematics for the 1993 RX7 and a 2008 RX8.

Assuming I want the full functionality of the 1993 RX7 fan relays (there are four of them), I think I need to do the following:

Fan#1 fed by connector B-05:
Bridge the positive (+) feeds from Connector B-05 (Y/W) and (R/W) to the Blue (L) wire of the the RX8 Fan motor #1. Ground will come from bridging (B) wire and (L/O) to Green (G) wire of the RX8 Fan motor#1.

Fan#2 fed by connector B-06:
Bridge the positive (+) feeds from Connector B-06 (Y/W) and (W) to the Red (R) wire of the the RX8 Fan motor #2. Ground will come from bridging (B) wire and (L/O) of connector B-06 to Black (B]) wire of the RX8 Fan motor#2.

However, the schematics show the RX7 fan-motors as 4-poles (two positive; two negative); and the RX8 fan-motors are 2-poles (single positive, and single negative).

Will this cause a problem ? Any back-feeding ? It doesn't seem like to me.

Moreover, before finalizing, I need to verify that adding +12VDC to either the Blue (L) or Red (R) wire of the RX8 fan-motors, will make them rotate in the the correct direction.

Man, nothing is SIMPLE about this car . . . .

:-) neil

PS: here's a mock-up of the wiring, any issues ?

So please correct me if I'm wrong (I did some research):

1. S1 ('04-'08) RX-8 fans have two different fan motors and are not the best solution for this mod, the motors have two wires coming out of them

2. S2 ('09-'12) RX-8 have two identical fan motors with 4 wires coming out of each motor, these are the ones you want, part number N3R1-15-150, motors can be found new and OEM for $55 per motor (for those that want brand new motors)

3. Fan blades are the same on S1 and S2 RX-8 (5 and 7 blades)

4. The fan blades from the RX-8 are the same as the upgraded '99 spec fan blades? :scratch:

So the best solution for this "mod" is to either:

a) find a complete fan assembly (shroud, fan motors and blades) from a '09+ S2 RX-8 and remove the motors and blades and place them into your FD shroud (what R7rexy did)

or

b) Buy brand new S2 fan motors and acquire new or used S1 or S2 RX-8 fan blades

Does this seem right? I don't even want to get into the electrical stuff right now...that's way beyond me at this point.

So is this something worth doing? Where I live summers can get pretty hot so anything that helps cooling is appreciated.

It seems to me that running some sort of PWM fan controller would be much easier since they are just 2 pole motors?

Or am I completely misunderstanding?

After reading DaleClark's Cooling Fan Control lecture ( https://www.rx7club.com/3rd-generati...system-906142/ ) and reviewing the Cooling Fan Control System diagram along with the RX8 series II diagrams, the only way to get the multi-speed multi-inputs is to use the Series II RX8 fan motors or stock motors.

If I want FULL fan all the time, it looks like I need to wire just both Series I RX8 fan to Fan Relay #1.

For about $100, I'm going to get NEW RX8 Series II fan motors.

:-) neil

Great info, thanks for sharing!

My set of RX8 fans just arrived, later series with 4 wires.

I will be replacing the stock rx7 fans and testing to see if coolant temps are any different back/back in same ambient temperatures / road temps

I have a fan controller as part of EWP unit. Plan was to wire both positive wires to a positive source off of a brand new high amp relay, then have both negatives connected to a constant ground. Have the relay triggered by the fan controller to flip on the juice. So this should be high speed or off, correct?

Or you could wire up the RX8 Fans the way GM does it with 3 relays. Low signal from Ecu switches the 3 relays to a series (6v each fan), high signal from the ECU converts the circuit to Parallel(12veach fan)


https://cimg4.ibsrv.net/gimg/www.rx7...2c188a59ce.gif

How easy is it to just pull the blades off and fit them to FD motors?

Super easy!

:-) neil

Cool thanks. i've got access to a junk rx8 so i'll be having those blades.

Does anyone know where I can get the RX8 Series II electrical connectors for the fan other than a junkyard ?

I like that it's a sealed connector unlike the FD's.

Thanks in advance,

:-) neil

I've fitted the rx8 fans to my FD rad, but the motor spindles are smaller than the holes on the rx8 fan blades.

cross pollinating threads
https://www.rx7club.com/3rd-generati.../#post12038066

This could be easily fixed by cutting a thin strip of aluminium from a coke can and wrapping it around the FD motor spindles. The rx8 fan holes are only marginally larger than the FD ones, so making the FD spindles a little fatter will do the trick.