Manual Fan clutch switch addition

[fstbmwm3]

Howdy folks,

Trying to steal 5-8hp from the stupid engine fan, I am contemplating adding a serially connected switch (extended to the cabin) that enables or disables the stock fan clutch that is engine driven.

My point is that when I run a 10 minute race or 1.45sec AutoX I do not worry about engine overheating.

I have already removed my all my A/C related components and the radiator is much cooler than before.

I do want to switch on (enable) the fan clutch on the cool down lap , at the pits and during the trip to and from the track.

Has anyone done it ? I dont want to do the -even better- BML racer solution that removes the fan and fan clutch since I live in the sunny Mediteranian.

Thanks in advance.

Regards,

Vlasis

[bimmer95]

Uhhhh, maybe you're confussed about how the fan clutch works. It's not an electrical clutch like an A/C compressor. There's no way to turn it on/off. There is fluid inside the fan clutch that lets the fan slip above a certain RPM/airflow.

[GR8 Ride]

I'd suggest removing the fan clutch, and going for an electric fan hooked up to a thermostat.

This is another of the essentially *no brainer* upgrades we recommend for dedicated track cars.


Pat

[fstbmwm3]

Are there bolt on radiator electrical fans ?

[fourfa]

yes. Look for the straight-blade Spal 16" thin fan for $80.

[JasonJ75]

http://home.earthlink.net/~rbirkz/E3...an_Install.htm

Nice writeup on how to do it all...Some feel its overkill...For me, considering I'm moving to a hot environment I'm going for as much cooling overkill as possible.

EDIT - Here's another...

http://www.bimmerforums.com/forum/sh...threadid=18949

[JonUK]

Originally posted by bimmer95
There is fluid inside the fan clutch that lets the fan slip above a certain RPM/airflow.

Does the M3 have a viscous fan the same as the rest of them? I thought it was temperature related, not RPM related...

I couldn't work out how spinning a freewheeling(ish) viscous fan could eat 8 horses... (or am I off the mark totally?)

[fourfa]

it doesn't exactly freewheel when hot. try it yourself, then think about spinning it at 7000 rpm.

[JonUK]

Originally posted by fourfa
it doesn't exactly freewheel when hot. try it yourself, then think about spinning it at 7000 rpm.

Shouldn't you have put a disclaimer about sticking fingers in it when spinning?

I'll have to try taking it off and going for a spin one day, see if I can notice the difference - I did some research, for about £100UKP I can pick up a 13" fan, adjustable stat and relay kit. My 325i doesn't have an aux fan, so I can't use that...

Jon

[GR8 Ride]

Actually, at engine idle it's not *too* bad to stick your fingers in and stop the fan.

The clutch is a pretty slick mechanism; I've done this a few times (accidental at first....then realized it's a good way to freak out newbies to the shop...).

I must admit, I haven't tried this at 7000 RPM, but then again, I'm reluctant to run my engine at redline with no load on it anyway.


Pat

[JonUK]

Originally posted by Bad-Karma
Actually, at engine idle it's not *too* bad to stick your fingers in and stop the fan.

I've chewed up magazines when I was trying to work out what was whistling when the engine was hot - I didn't want to risk broken fingers

[fourfa]

I'm starting to wonder how much stiffer it gets with age. My fan clutch with 60,000 miles is pretty hard to hold back when hot.