David Massey wrote:
>
> You wrote:
>
> >Dave:
>
> >In my original post, I said "for the same cooling." That applies to
> whatever
> >RPM the engine is operating at. If it takes 21.6 HP to operate the
> mechanical
> >fan at 4800 RPM, it will take at least 26 HP to operate an electric fan
-------------------------
Enough Fans already. You can't really compare an electric to a pure
mechanical. The duty cycle is obviously different. You do pick up
horsepower improvements when the fan is not required. The fan clutch is
similar but uses a silcone fluid within the clutch activated by the
blast air temp @ the clutch bimetal coil.
Really guys I know first hand that one manufacturer put a larger V8 into
a sport Ute and picked up significant H.P. This particular vehicle with
the smaller 5.2L did lose 18 measured H.P. with the 5 blade mechanical
fan that appears to have more surface area/pitch and moves more air
through the heat exchanger than our TR6's.
The ideal is a fan that comes in when you need it only, not spin all the
time even when ram air at vehicle speed exceeds requirement. Generally
if the cooling system is sized correctly that would be at idle or during
city traffic at high ambients.
My TR6 mechanical (71 is a poor performer) runs hot even with a 180
thermostat.
I have some electrics I'm going to try on the 74 I'm building now.
Just my .25 cents worth
Glenn Franco
71 & 74 TR6's
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