re: Clutch Fan removal

[alex.fadeev@xxxxxxxxxxx]

Barry <jkerouac@domain.elided> wrote:
> 
>       Following a link given on this digest to www.Understeer.com,
> I found an article about removing the clutch fan in order to gain an
> effective increase in acceleration, even though the net power output
> of the engine is not increased.  This is due to not needing to turn 
> the mass and air resistance of the fan.  The mod works to a 
> noticeable degree.

True enough. 
Main engine fan delete is one of the popular track mods. 
Actually, some of E36M3 friends run without main fan, with AC ON in stop 
and go Dallas TX traffic in the peak of the summer and get away with it. 
To the best of my knowledge, no one had reliably measured how much HP the 
main fan draws with the viscous clutch disengaged, partially engaged or 
fully engaged. Thus it is impossible to compare the engine loads between 
the stock viscous clutch fan and the auxiliary electric fan when it kicks 
in to provide extra cooling. But as long as the electrical fan is OFF, you 
might be lowering the accessories' draw on the engine by 1-3 extra ponies. 

Not something 99% of the people on this list are likely to feel in real 
life. Nor something one can measure on a dyno (will likely fall within the 
margin of error).

>      The liability here can be due to decreased engine cooling under
> 10mph, with no air circulating through the radiator of course when
> standing still except what the low setting on the dual speed electric
> fan gives.  In most weather conditions this low fan speed is entirely
> insufficient on its own to keep the engine at or below thermostat
> opening temperature. 

There is nothing magic about keeping thermostat closed or partially open 
on a car. 
Fan-less E36M3 owners report no signs of overheating even in Dallas summer 
heat (95-110F May through September). So the low speed of the BMW 
auxiliary electric fan is plenty adequate even with AC ON (extra heat from 
the condenser).
I am not one of them for the reason of durability. Having shelled out $280 
for a replacement eclectic auxiliary fan on my E30, I'm in no hurry to run 
my E36M3 fan into the ground. 
Plus I can still win my autoX class with the main fan in place, so why 
bother. 

>       I have not seen it presented in either the Understeer.com 
> article or elsewhere the following simple change to the electric fan
> switch connector that gets you the high fan speed as soon as the switch
> reaches what would have been the low speed setting. 

Entirely unnecessary.

alex f

------------------------------