On 7 Dec 2005 at 16:32, Barrie Robinson wrote:
---snip---
> My main reason for
> coming down to this side is a basic premise that if it is better to
> have air belting over radiators (powerful electric fans) then the
> same must apply to water screaming down the radiator tubes.
Exactly.
> The
> other is a simple premise, slower water will take up more heat and
> thus the temperature difference between it and the tubes cooled by
> air flow is made smaller.
Barrie, this is simply not the case. Heat doesn't care if the medium it's going
into or out
of is moving fast, slow, or not at all. The only thing slowing down the coolant
will do is
cause it to get hotter. Hotter is not better. The hotter the coolant gets, the
less heat it
will absorb (all other things being equal). You don't want the coolant in your
engine to
remain there long enough to get hot, any more than you want the air around the
fins of
your radiator to remain there long enough to get hot.
---snip---
>
> One point that was made was that the removal of a thermostat resulted
> in a lowering of the pressure to the block (water pump hump!), which
> dropped the boiling point, which effected cooling.
This is a measurable effect, but it's minor compared to everything else going
on in your
cooling system. Automotive water pumps have huge clearances and are designed
for
high volume, not high perssure.
>
> But most compelling was a web page from Stewart Components
> www.stewartcomponents.com (Tech Tip 3) sent to me by Jim Stuart. It
> laid it all out and said slow speed water is a myth -
Good. I hope we've finally killed this myth...
>
> However after the Christmas holidays I shall set up a test rig just
> to test flow against heat dissipation. .....and maybe the use of
> Water Wetter about which I have doubts.. And before I get emails
> saying all the NASCAR people use it - they also use STP, Coca Cola,
> Febreeze, and used to promote cigarettes.
Good point. Remain skeptical, it's healthy. However:
Water Wetter breaks down the surface tension of the coolant, but since the
entire
cooling system is completely submerged (so to speak) it's hard to imagine that
surface
tension plays any part at all. Anecdotal evidence seems to show that surface
tension
does indeed play a part, however.
I'm personally a believer in Water Wetter, as I've seen noticeable improvements
by
using it. I've also used a few drops of dish detergent, which does the same
thing,
however I wonder if the dish detergent affects the coolant chemistry enough to
cause it
to attack aluminum or brass parts. I currently have a few drops of dish
detergent in my
Jaguar, and it makes just enough difference to keep it from overheating.
Marvin
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