Re: watter (sic) wetters

[Don Hoefer <hoefer@eng.pko.dec.com>]

Jeff Loh wrote:

> 
>      Water wetters, by reducing the surface tension of the fluid,
> increase
>      the efficiency by which thermal transfer occurs. Therefore, it
> makes
>      the fan better able to extract heat from warmed coolant. There
>      _should_ be a measureable difference. On our race cars emprical
>      evidence shows that cylinder head temps are lowered after adding
> water
>      wetter.
> 

There won't be a measurable difference in the water temperature
but there will be a measurable difference in the duty cycle of
the fan, if the stuff works.  The water temperature is controlled
by the thermostat and will remain about the same under any
circumstance unless the cooling system is marginal.  Assuming
better heat transfer, very hot components (like the head) will
be cooler.

Don Hoefer
'82 Coupe