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View Full Version : question about FDM


Myee
08-28-2006, 09:32 AM
I understand the benefit of losing the mechanical fan, but why don't people replace it with electric fans instead of running off of the aux fan only?
LynxZ3r0
08-28-2006, 09:59 AM
I deleted BOTH my fans. :)

SPAL 16" Curved Blade Puller in place of the mechanical fan.

Cools plenty.
Myee
08-28-2006, 10:32 AM
See thats the thing, all of the FDM kits Ive seen include a T-Stat and Water Wetter, but no aftermarket E-fan
LynxZ3r0
08-28-2006, 10:50 AM
The stock electric is more than enough to move the air on a (mostly) stock motor. The only time you should have to worry at all is if you are going FI.

A few people have replaced both fans w/ a single 16" SPAL puller, but it's not needed in most cases.

The only thing that becomes a critical issue because of that, however, are coolant change intervals (once a year). Old coolant will quickly lead to overheating w/ only 1 fan.
M52 POWER!
08-28-2006, 12:32 PM
An electric fan will take away more power than the mechanical fan since the alternator has to work harder to spin it aswell, plus you're converting mechanical to electric then back to mechanical there is always extra power loss from friction.
catchuk
08-28-2006, 10:45 PM
I really think price has alot to do with it. Aftermarket electric fan systems are quite costly, at least for the e39!
944attack
08-28-2006, 11:55 PM
An electric fan will take away more power than the mechanical fan since the alternator has to work harder to spin it aswell, plus you're converting mechanical to electric then back to mechanical there is always extra power loss from friction.

true, my car comes with 2 electrical fans side by side, and i know some race car teams take off one for this reason. Of course they have an upgraded radiator though.


not that my comment helps in any way, just an odd fact. :blah:
SlickShift
08-29-2006, 09:39 AM
Random question...why did my steptronic E46 have two fans and my manual one only have one?
TheDarkSide
08-31-2006, 11:51 AM
Over my head :shrug:
LynxZ3r0
08-31-2006, 12:08 PM
Random question...why did my steptronic E46 have two fans and my manual one only have one?

No clue. Makes no sense to me. Most companies do the opposite figuring that the manual tranny drivers will redline more often and require the extra cooling.
TheDarkSide
08-31-2006, 12:49 PM
Different year is my guess. Don't think it has anything to do with tranny.
SlickShift
09-01-2006, 03:27 PM
I know it has to do with the tranny because all the DIYs or power pullies say how the autos are harder to install since there's an extra fan.
TheDarkSide
09-01-2006, 06:12 PM
:shifty: Weird