"MLD" > wrote in message ...
>
> "Guv Bob" > wrote in message
> m...
> "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.
>
> Found this Flow vs Delta P characteristic.
> http://www.bing.com/images/search?q=...urve&FORM=IGRE
>
> MLD

Thanks. Still looking for RPM vs Floweret