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Z4M electric fan retrofit?

25K views 50 replies 20 participants last post by  tangerine-dream 
#1 ·
I've been contemplating deleting the mechanical fan, but I don't really want to go with an aftermarket solution. I've been tempted to retrofit the non-M electric fan, but always held back because I'm not sure if it would be powerful enough (I think it'll fit though. Radiator brackets seem to be the same).

Now looking at the z4m - it has a 600W electrical fan (compared to the 390w fan in the non-Ms). Mounting points are identical to the e46 non-M fan. I'm thinking this should do the trick since it's from an s54 car. And it should into the existing connector. One potential issue is that the z4m comes with a different radiator (same radiator as e46 non-M actually). Another issue is that it's expensive ($500 shipped at thebmwpartstore.com)

Before I attempt this - has anyone attempted either this fan or the non-M electrical fan? Can they at least mount up? If not, how difficult would it be to retrofit whatever piece has the screw holes? (would I need a new radiator or can I just swap some plastic bits?)
 
#38 ·
bump...
 
#39 ·
I finally got a decent deal on a used one. Unfortunately my car will be parked very soon. If it arrives before I park it I'll take my fan out and mock it up for you guys.
 
#40 ·
I realized that the Z4M doesn't have the fan controller built onto the assembly like our aux fan. Does anyone know where it is located? I'm considering leaving the front aux fan all stock as is, and adding this secondary fan and controller and tieing off the same inputs as the other controller that way they both function the same rate etc.
 
#46 · (Edited)
Hrm I guess that is true. Guess I'm just being paranoid reading all these issues of people converting to electric fans and overheating. I do also have an intercooler in the way.

But I think you're right and I'll try it with the aux removed entirely.

I'm going to grab an old junker E46 NonM fan and rob the connector off it and then get the proper connector from BMW for the Z4 fan that way I can make my own proper adapter harness. Interestingly enough, I also found out the Non E46 M puller fan has the same fan control module as the M3 pusher fan. I wonder what the wattage is on the M3 pusher fan. Can't seem to find any documentation of that anywhere. Either way. If the 390 watt is fine for the manual non M cars. then the 600 should be more then suffice for me. Will keep you guys posted. It still seems no one has really done this yet so I want to keep it all documented.
 
#47 · (Edited)
FYI. I have the z4M fan mounted onto an E46M3 rad. It fits pretty well. The two holes at the top for the push pins are slightly off so you'll have to be a bit creative but it does fit the radiator. It overhangs below to where the oil cooler would be but that may be more beneficial for oil cooling. It hangs down by about 2"

But for the most part. It fits the radiator almost perfect. It clips over the edge of the radiator and slides into the side mount and the width is identical. This may be the a HUGE discovery as I don't think anyone has done this yet. I have a factory E46 Aux plug which I will be splicing into the Z4M Fan so it's a true plug and play swap. The biggest things now will be if it will clear the water pump nut and if it does indeed cool the same or better.

I will be recoding the DME to have the fan turn on a bit earlier then factory. This will be taking place of the factory mechanical and aux fan just like the Z4M as this fan is dual purpose and at 600w, the Z4MN guys never have overheating issues but they do have a larger engine bay for more air flow.

I will be making a new thread with pics soon but I don't think I'll be getting around to installing this for a while still.

Tom
 
#49 ·
Just to update everyone... The Z4M fan does NOT fit. It's too thick. and tall. You can't even slide it in between the radiator and vanos unit. And then if you could get it passed there, the shroud for the oil cooler would be in the way as the Z4M fan shroud is taller then stock and you would have to cut off a couple inches of the bottom of the fan shroud or of the oil cooler shroud to clear it and hope the fan blades don't hit.

Even after all that if you could get it to fit, the fan is literally sandwiched in there and I'm sure at that point, any gains from the fan are reduced significantly from air restriction as there is no easy path for the fan to exhaust the hot air to as it hits the front of the engine immediately.

Too bad :(
 
#50 · (Edited)
Have you looked at maybe somehow trying to measure the CFM of the Z4M fan and then just find an aftermarket puller/pusher fan that can roughly match that instead of the Z4M now you found it doesn't fit?... a pusher might be easier as I think you have more space there when you delete the aux fan then you do behind the radiator with a puller when you delete the mech fan...

Either way are you going to continue to investigate a way to replace both the aux and mech fan with a single electric fan? (now you have just excluded the Z4M setup as an option)
 
#51 ·
Early E85 Fan Might Work

Hello - Well I am going home for Christmas. So I want to try this retrofit in preparation for a supercharger upgrade this Summer. Right now I have the clutch fan and aux fan up front.

I believe it may work on the non-M auto 3.0L sedan/wagon. It was stated that the Z4 600W electric cooling fan would NOT work on the M3 due to lack of space or clearance. I hope with a little customizing things will work out on my car, or better yet, it might just fit!




However, some concerns exists such as:

1. Additional 16V due to wattage increase
2. Heat dissipation on higher gauge stock wires
3. Strain on stock alternator
4. Wires melting from higher current/resistance
5. Fire

Q: Wouldn't the 50A fuse work in the capacity to prevent 4 or 5 from happening?

I believe the formula works out using the 600W fan right a 50A fuse as max.

Thinking...this would be similar to a house having a fuse or circuit breaker to prevent overloading thus breaking - right?

Your thoughts? Thank you!!
 
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