Originally Posted by Adjuster

It's just my 1998 A8 was a belt driven fan with a fan clutch, and my 2004 A8L has only electric fans.

I also realize you can't just run two fans off the controller, thus, using only the fan power to trip the relay, and use at least a 30 amp relay, wired into a source of main power, with it's own seperate fuse and ground.

I agree that most mechanical fans do a great job, but if the bearing is xx.xx dollars to replace, and a large electric fan, relay and fuse is less, why not try the DC fan? (I know of a kit that is sold with two fan sizes available using this same setup for the most part.)

I would only consider hooking up to a fan that is not dependent on the AC system to get a signal to work.

On cold days, my current ride does not run the DC fans much at all, but on hot days, it sounds like a 737 on take off at times, and the "wind down" noise after shutting of the engine is classic large fans spooling down.

A big advantage is at speed, the DC fans are not needed for 99% of the time, so you are not dealing with the drag on the engine, or the alternator.

I would only consider this if the bearing was not needed however. If you need the bearing there for the fan, just to have the belt turn a now empty pully, it defeats the purpose too.

Just thinking outloud here, and I have seen some aplications where DC fans do not work nearly as well as the OEM fan/clutch setup.