radiator caps, cooling system pressure

On Tue, 13 May 2014 15:15:49 -0800, "Guv Bob"
> wrote:

>"MLD" > wrote in message ...
>>
>> > wrote in message
>> ...
>> > On Sun, 21 Apr 2013 18:50:29 -0700 (PDT), "
>> > > wrote:
>> >
>> >>On Apr 21, 6:11 pm, Tony Hwang > wrote:
>> >>> Ashton Crusher wrote:
>> >>> > I was thinking of putting a higher pressure cap on one of my cars to
>> >>> > increase the factor of safety against boiling. Looking thru the web
>> >>> > for info on the likelihood of changing from 7 psi to 13 psi causing
>> >>> > leaks I found little on that issue but did find a couple references to
>> >>> > the pressures created by the water pump. One site boasts of a 19 PSI,
>> >>> > $25 cap to get you thru your "hard driving".
>> >>> >http://www.mishimoto.com/mishimoto-h...tor-cap-13-bar....
>> >>> > Thought I'd see if anyone else has heard of this. The claim was that
>> >>> > the water pump could create over 30 PSI of pressure. Since that is
>> >>> > double the normal operating pressure of most modern cars I find it
>> >>> > hard to believe. If the system was at full 15 psi of pressure while
>> >>> > the car is idling and then your floored it and ran it up to near
>> >>> > redline and created another 30psi of additional pump pressure, or
>> >>> > even 10 psi of additioingnal pressure downstream at the radiator cap,
>> >>> > you
>> >>> > would immediately cause the system to have to vent to the overflow to
>> >>> > relieve this higher pressure. I've never seen a car vent due to me
>> >>> > revving the engine up while I'm working on it. Thoughts?????
>> >>>
>> >>> Hi.
>> >>> There is a over flow bottle for coolant/anti-freeze. Ever
>> >>> cleaned/flushed your rad. and maintain proper level of
>> >>> coolant/anti-freeze in your rad.? If the car is old, messing with cap
>> >>> can spring
>> >>> a leak.- Hide quoted text -
>> >>>
>> >>> - Show quoted text -
>> >>
>> >>AMEN!
>> > A water pump cannot produce system pressure because it just moves
>> > water from one side of the pump to the other. Expansion due to heat is
>> > what builds pressure..
>>
>> I guess you need to know how a centrifugal pump works. Pressure rise
>> across the pump is function of the square of its speed. Double the pump
>> speed and the delta P across the pump increases 4X. Expansion due to heat
>> will increase system pressure if it is in a closed system. If a fluid can
>> expand without being constrained---no significant change in pressure.
>> MLD
>
>MLD, do you know where to find a flow rate vs RPM curve for any common stock water pumps? I'm surprised I can't seem to find anything mfr spec curves at the various mfrs and parts houses. Doesn't matter what mfr or vehicle -- just any common street car single head pump.
>

I was looking to see what I could find on water pumps and didn't find
much. I did come across this
http://teae.org/cooling-the-tiger/
which is pretty interesting though. A bunch of home experiments
looking at what things make for better cooling.