On Wed, 14 May 2014 23:43:00 -0800, "Guv Bob"
> wrote:
>"Ashton Crusher" > wrote in message ...
>> 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.
>
>Thanks, that's very interesting info. I'm not familiar with the particular car they are doing the testing with, but it seems odd to me that they consider coolant temps below 212 deg F as normal. They must be water with no glycol in a system open to atmosphere. However, I didn't read it that closely thought so (as most people say) I may be off.
Below 212 is normal. Anything over is abnormal, but still safe untill
the BP of the pressurized mixture is exceded. Normal Operating Temp is
closer to 195F-215F