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radiator caps, cooling system pressure



 
 
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  #61  
Old May 14th 14, 07:51 AM posted to rec.autos.misc,alt.home.repair
Ashton Crusher[_2_]
external usenet poster
 
Posts: 2,874
Default 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.
Ads
  #62  
Old May 15th 14, 08:43 AM posted to rec.autos.misc,alt.home.repair
Guv Bob[_4_]
external usenet poster
 
Posts: 18
Default radiator caps, cooling system pressure

"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.

  #63  
Old May 15th 14, 05:12 PM posted to rec.autos.misc,alt.home.repair
[email protected]
external usenet poster
 
Posts: 931
Default radiator caps, cooling system pressure

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
  #64  
Old May 18th 14, 12:39 AM posted to rec.autos.misc,alt.home.repair
MLD
external usenet poster
 
Posts: 74
Default radiator caps, cooling system pressure


"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

  #65  
Old May 21st 14, 08:53 PM posted to rec.autos.misc,alt.home.repair
MLD
external usenet poster
 
Posts: 74
Default radiator caps, cooling system pressure




"Guv Bob" > wrote in message
m...
> "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


You're right, not an easy thing to find. Why not give one of the many
manufacturers a call and ask for what you want.
MLD


>

  #66  
Old May 21st 14, 09:05 PM posted to rec.autos.misc,alt.home.repair
Guv Bob[_4_]
external usenet poster
 
Posts: 18
Default radiator caps, cooling system pressure

"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

  #67  
Old May 24th 14, 04:32 PM posted to rec.autos.misc,alt.home.repair
Rick[_22_]
external usenet poster
 
Posts: 4
Default radiator caps, cooling system pressure


> wrote in message
...
> On Fri, 02 May 2014 00:28:35 -0700, mike > wrote:
>
>>On 5/1/2014 9:08 PM, Rick wrote:
>>>
>>> "mike" > wrote in message
>>> ...
>>>> On 5/1/2014 4:46 PM, MLD wrote:
>>>
>>>
>>>> operation
>>>> can the pressure on the output side of the pump significantly exceed
>>>> the pressure on the input side?
>>>
>>>
>>>
>>> Yes, and it looks like a lot of you have no idea how much it can, and
>>> does.
>>>

>>I'd like to hear the rationale in a closed system.

> Restriction to flow affects the "head" of the pump. No restriction,
> no head pressure. A good water pump may produce a 5 psi head, and draw
> an equivalent depression on the low side of the pump for a maximum
> pressure differential of 10psi - but that is a "blueprinted" pump at
> optimal speed with an adequately restrictive radiator.
>
> Real world numbers are generally quite significantly less. Measured
> 3psi on BMW 328 just this week at 3000 RPM. Above and below 3000 it
> dropped off. That was with diluted coolant (about 20-25% glycol) due
> to having just repaired a leak and having the normal "fun" bleeding
> all the air out of the nasty little Kraut!!


Having performed thousands of automotive cooling system flow/pressure and
pump performance tests, I can say you have no idea, either.

Without getting into particulars, recently....5500 pump RPM...10 psi at the
pump inlet, 200+ GPM into the block at 80 PSI pump outlet pressure

 




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