I would just like to say that I'm having a hard swallowing the "certain
amount of time" theory for heat transfer. When you get into a complex
system, such as cooling an engine, there may be unseen or un-thought of
relationships, such as heat transfer taking place in more than one location.
This may end up meaning that slowing down the coolant will lower the engine
temperature. However, I can guarantee that it is not because the amount of
time the coolant stayed in contact with the engine or radiator surface
allowed it to "pull more heat". In fact the opposite is true, because
according to Newton's law of cooling the smaller the temperature difference
the less heat will be transferred. So the longer the coolant stays in
contact with the engine, the hotter it will get and the coolor the engine
will get, lessening the temperature difference and thus the amount of heat
that will get transferred. Likewise in the radiator, the longer it takes to
go through, the cooler it gets, lessening the temperature difference, and
correspondingly the amount of heat transferred.
Now it has occurred to me that there is a fundamental difference between the
heat gain from the engine and the heat loss through the radiator. Iin the
engine you've got the coolant heating up and the engine cooling down, while
in the radiator you have only the coolant cooling down, the (incoming) air
doesn't get any hotter. Maybe this is why in some instances slowing down the
coolant will cool the engine.
<dnw>
1972 Midget
1998 Safari
1999 9-3
1964 (Me)
----- Original Message -----
From "Kansa, Robert" <KansaR at diebold.com>
To: "'Geoff Branch'" <gjbranch@mediaone.net>
Cc: <spridgets@autox.team.net>
Sent: Friday, September 28, 2001 9:29 AM
Subject: RE: "Oil Pressure" & "old" overheating problem
> theres a certian amount of time the water must remain in contact with the
metal to pull the heat from it, and the same goes for dissipating it through
the radiator. you want to have both, within certian limits,, the big pully
theory will only work for cars that are kept in high rev situations for
extended amounts of time..as in racing..and we are talking 6-8+k rpm...not
5-...if you suspect cavitation, a water wetter might help a bit, but you may
need a swirl tank, and are we talking a 130+bhp car?.
>
> R(wnik)Kansa/RCCSA
> 100+hp 1275 cool sprite
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