On Tue, 23 Apr 2013 18:26:08 -0400, Nate Nagel
wrote:

On 04/22/2013 02:50 PM, Ashton Crusher wrote:
On Mon, 22 Apr 2013 08:57:20 -0700 (PDT), harry
wrote:

Thoughts?????

One other possibility is you may have a blown head gasket.

I didn't want to make the original post into a novel but it appears a
lot is being read into what wasn't included. That car is not having
any problems at all right now. I'm just looking at increasing the
factor of safety against overheating because I just added AC to it.
Non-ac cars use a 7 pound cap and AC uses 13. But it's a 52 year old
car (well maintained) and the downside would be if adding 6 pounds
more pressure is likely to create any leaks, like in the 52 year old
heater core. Nothing leaks now. I'm just torn between being
proactive and getting a higher pressure cap "just in case", or just
sitting tight and seeing how the temperatures run as the weather heats
up.


Like I said in a previous post, a coolant recovery bottle would be my
first step... I never did like seeing that air gap at the top of the
radiator, and it's not good for anything to have it there.

nate


Prior owner put one on it and it seems to be working correctly.

On Thu, 25 Apr 2013 18:02:36 -0700, Ashton Crusher
wrote:


Heater cores in many many cars are a pain to replace. Lots of things
on top of them, including parts of your recently added AC, which iiuc
doesn't use rubber hoses, uses metal hoses. Am I right about that?


Since this is an added ac it won't interfere much with the original
heater. Here in AZ it's not unusual for bad heater cores to just be
bypassed :-)

I did that once. I had a leak, a hose spraying iirc, just as we
arrived outside some Federal building, not a museum, just south of the
Mall in DC. My friend's girfriend worked there and we were picking
her up at the end of the day. She took me down to the engineer's room
and he gave me a piece of pipe 2 or 3" long. Now I probably
couldn't get into the building even if I needed blood.

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 wrote:

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

Hi,
It would also matter how hot the water already is.
How old is the car? Is the rad fan. electric?
Thermo. clutch driven with belt?
Or real old car with straight belt driven? No water temp.
gauge on the dash?(very good idea to have one)

"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

Well, I give each of you half credit. LOL! At a certain RPM, the pump head (outlet-inlet pressure) and flow rate are both are fairly indept of the coolant temperature as long as the coolant stays a liquid (normal condition) when going through the pump. The engine heat raises the coolant temperature and the pressure (remember this from skool... PV=nRT), but (and this is a big butt) as long as the pump turns at the same RPM, the head should stay about the same.

FWIW, here's a decent drawing of a water pump cross-section
http://assets.hemmings.com/story_image/83720-500-0.jpg

"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

Well, I give each of you half credit. LOL! At a certain RPM, the pump head
(outlet-inlet pressure) and flow rate are both are fairly indept of the
coolant temperature as long as the coolant stays a liquid (normal condition)
when going through the pump. The engine heat raises the coolant temperature
and the pressure (remember this from skool... PV=nRT), but (and this is a
big butt) as long as the pump turns at the same RPM, the head should stay
about the same.

FWIW, here's a decent drawing of a water pump cross-section
http://assets.hemmings.com/story_image/83720-500-0.jpg

A couple of comments--PV=nRT is an equation used in gas flow calculations
not when the fluid is a liquid. Don't understand where you are coming from.
Just for the record, at constant speed the pressure rise across a
centrifugal pump does not remain constant. Typically, there is a droop
(loss of delta P) as the pump flow demand increases. Relatively
insignificant at first but if the flow demand gets large enough, then the
Pump Delta P can drop significantly. Flow demand is dictated by the
characteristics of the the system in question--that is, how the delta P vs
Flow of the system (line losses etc.) matches up with the delta P vs flow of
the pump. Where the two intersect will be the operating point of the
System. The idea is to match them so that the intersection takes place
where the droop in pump deta P is relatively insensitive to flow demand.
MLD

On 5/1/2014 9:39 AM, MLD wrote:

"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

Well, I give each of you half credit. LOL! At a certain RPM, the pump
head (outlet-inlet pressure) and flow rate are both are fairly indept of
the coolant temperature as long as the coolant stays a liquid (normal
condition) when going through the pump. The engine heat raises the
coolant temperature and the pressure (remember this from skool...
PV=nRT), but (and this is a big butt) as long as the pump turns at the
same RPM, the head should stay about the same.

FWIW, here's a decent drawing of a water pump cross-section
http://assets.hemmings.com/story_image/83720-500-0.jpg

A couple of comments--PV=nRT is an equation used in gas flow
calculations not when the fluid is a liquid. Don't understand where you
are coming from. Just for the record, at constant speed the pressure
rise across a centrifugal pump does not remain constant. Typically,
there is a droop (loss of delta P) as the pump flow demand increases.
Relatively insignificant at first but if the flow demand gets large
enough, then the Pump Delta P can drop significantly. Flow demand is
dictated by the characteristics of the the system in question--that is,
how the delta P vs Flow of the system (line losses etc.) matches up with
the delta P vs flow of the pump. Where the two intersect will be the
operating point of the System. The idea is to match them so that the
intersection takes place where the droop in pump deta P is relatively
insensitive to flow demand.
MLD

Riddle me this.
In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is
whatever
the pressure is.
The pump can't put more pressure on the output side than is on the input
side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.

Do pump principles applied to OPEN systems really apply?

On 5/1/2014 4:46 PM, MLD wrote:

"mike" wrote in message
...
On 5/1/2014 9:39 AM, MLD wrote:

"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

Well, I give each of you half credit. LOL! At a certain RPM, the pump
head (outlet-inlet pressure) and flow rate are both are fairly indept of
the coolant temperature as long as the coolant stays a liquid (normal
condition) when going through the pump. The engine heat raises the
coolant temperature and the pressure (remember this from skool...
PV=nRT), but (and this is a big butt) as long as the pump turns at the
same RPM, the head should stay about the same.

FWIW, here's a decent drawing of a water pump cross-section
http://assets.hemmings.com/story_image/83720-500-0.jpg

A couple of comments--PV=nRT is an equation used in gas flow
calculations not when the fluid is a liquid. Don't understand where you
are coming from. Just for the record, at constant speed the pressure
rise across a centrifugal pump does not remain constant. Typically,
there is a droop (loss of delta P) as the pump flow demand increases.
Relatively insignificant at first but if the flow demand gets large
enough, then the Pump Delta P can drop significantly. Flow demand is
dictated by the characteristics of the the system in question--that is,
how the delta P vs Flow of the system (line losses etc.) matches up with
the delta P vs flow of the pump. Where the two intersect will be the
operating point of the System. The idea is to match them so that the
intersection takes place where the droop in pump deta P is relatively
insensitive to flow demand.
MLD

Riddle me this.
In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is
whatever
the pressure is.
The pump can't put more pressure on the output side than is on the input
side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.

Do pump principles applied to OPEN systems really apply?

Don't understand either of your comments. Could you expand your
explanations so they make some sense?
Do you know what happens if you dead end a centrifugal pump (Zero flow)
while its running?? The discharge pressure might not change but you
better be prepared to see the fluid temperature skyrocket.
You seem to to make a big point out of INCOMPRESSIBLE fluid. Got some
news for you, Ready---fluids, aka liquids, are not INCOMPRESSIBLE!!!
Have you ever heard of "Bulk Modulus", entrained air or compressible
flow as they apply to liquids?
Do you know what would happen to the pressure in a closed system if the
fluid temperature (say water) was increased but the fluid was not able
to expand due to the closed (or fixed) system volume?
Hint: Delta P=(BM) x (Delta V)/V
Clue: Pressure can increase up to the thousands! Want to try and
conduct your own experiment? Close the water inlet shut off valve in
your house. Keep all faucets closed and of course, lock the hot water
tank relief valve so that it doesn't open. Now just crank up the
temperature of your water heater. This ought to seek out your system's
weak link.
MLD


Can't argue with your theory. Problem is that it doesn't apply here
in any significant amount.
If the pressure exceeds the cap pressure, it vents.
The pump didn't add the pressure. In your scenario, the pump added
heat.
So, get back to the topic. In a closed car cooling system under normal
operation
can the pressure on the output side of the pump significantly exceed
the pressure on the input side?

I think we can exclude any vaporization of the liquid leading to excess
pressure. If it did, it would vent and, eventually, there'd be no more
liquid to pump.

But thank you for the clue and the hint and the nitpicking.

On Thu, 01 May 2014 17:05:57 -0700, mike wrote:

On 5/1/2014 4:36 PM, Ashton Crusher wrote:
On Thu, 01 May 2014 12:59:51 -0700, mike wrote:

On 5/1/2014 9:39 AM, MLD wrote:

"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

Well, I give each of you half credit. LOL! At a certain RPM, the pump
head (outlet-inlet pressure) and flow rate are both are fairly indept of
the coolant temperature as long as the coolant stays a liquid (normal
condition) when going through the pump. The engine heat raises the
coolant temperature and the pressure (remember this from skool...
PV=nRT), but (and this is a big butt) as long as the pump turns at the
same RPM, the head should stay about the same.

FWIW, here's a decent drawing of a water pump cross-section
http://assets.hemmings.com/story_image/83720-500-0.jpg

A couple of comments--PV=nRT is an equation used in gas flow
calculations not when the fluid is a liquid. Don't understand where you
are coming from. Just for the record, at constant speed the pressure
rise across a centrifugal pump does not remain constant. Typically,
there is a droop (loss of delta P) as the pump flow demand increases.
Relatively insignificant at first but if the flow demand gets large
enough, then the Pump Delta P can drop significantly. Flow demand is
dictated by the characteristics of the the system in question--that is,
how the delta P vs Flow of the system (line losses etc.) matches up with
the delta P vs flow of the pump. Where the two intersect will be the
operating point of the System. The idea is to match them so that the
intersection takes place where the droop in pump deta P is relatively
insensitive to flow demand.
MLD

Riddle me this.
In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is
whatever
the pressure is.
The pump can't put more pressure on the output side than is on the input
side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.

Do pump principles applied to OPEN systems really apply?


Great Question. My original question remains unanswered .... Does the
water pump ADD another 10 to 30 psi internal pressure (as the sources
I originally was looking at claimed) and if it does, how come that
extra pressure, on top of the already existing 12 psi heat pressure,
not cause the cap to blow off from the excess pressure now totaling
from 20 to 40 psi? All I can think is that the pump only adds perhaps
2 to 5 psi and that by the time it "gets" to the cap area, flow
resistance has dissipated it down to 1 or 2 psi and it has ceased to
be a problem. Or maybe the pump only "adds" negative pressure, i.e.
suction at the inlet, or some combo of all that.

It's my contention that the pump can add no pressure unless it has
somewhere to get the water to pump.
If it's coming from the closed system, there ain't none available
unless you vaporize some on the source side.

The water pump can develop mabee a couple of pounds pressure on the
outlet side into a plugged rad with the cap off. With the cap on, with
no air in the system, significantly less. But at best, only a pound or
two. Will running the water pump dead headed cause a temp increase?
Sure, a very small amount. Inconsequential compared to the heat output
of the engine. It will NOT cause a pressure increase in the closed
system. The increased pressure increases the boiling point of the
coolant. It also helps get and keep entrained air out of the cooling
fluid. The only thing that causes the pressure rize is temperature.
The pressure reduces back to atmospheric when the temperature drops
back to room temperature. Current production vehicles have a "catch
tank" that holds excess coolant if any is forced out to regulate the
pressure, and it is drawn back in on cooldown.

"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.

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.

On Thursday, May 1, 2014 3:59:51 PM UTC-4, mike wrote:
On 5/1/2014 9:39 AM, MLD wrote:



"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



Well, I give each of you half credit. LOL! At a certain RPM, the pump

head (outlet-inlet pressure) and flow rate are both are fairly indept of

the coolant temperature as long as the coolant stays a liquid (normal

condition) when going through the pump. The engine heat raises the

coolant temperature and the pressure (remember this from skool...

PV=nRT), but (and this is a big butt) as long as the pump turns at the

same RPM, the head should stay about the same.



FWIW, here's a decent drawing of a water pump cross-section

http://assets.hemmings.com/story_image/83720-500-0.jpg



A couple of comments--PV=nRT is an equation used in gas flow

calculations not when the fluid is a liquid. Don't understand where you

are coming from. Just for the record, at constant speed the pressure

rise across a centrifugal pump does not remain constant. Typically,

there is a droop (loss of delta P) as the pump flow demand increases.

Relatively insignificant at first but if the flow demand gets large

enough, then the Pump Delta P can drop significantly. Flow demand is

dictated by the characteristics of the the system in question--that is,

how the delta P vs Flow of the system (line losses etc.) matches up with

the delta P vs flow of the pump. Where the two intersect will be the

operating point of the System. The idea is to match them so that the

intersection takes place where the droop in pump deta P is relatively

insensitive to flow demand.

MLD



Riddle me this.

In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is

whatever

the pressure is.

The pump can't put more pressure on the output side than is on the input

side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.



If the pump can't put more pressure on the output side, then what
exactly makes the water flow? Why does the water flow faster the faster
the pump runs? Even in an open system, like a pool, the system is under
pressure, atmospheric pressure. In an engine cooling system, the
overall pressure of the whole system will rise with temp, but there is
still a pressure delta across the pump.



Do pump principles applied to OPEN systems really apply?

Yes, of course they do.

On Friday, May 2, 2014 3:28:35 AM UTC-4, 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.

It's exactly the same rational as in an open system. If there is no
pressure difference in a closed system, why would the pump move water
at all?

On Thursday, May 1, 2014 8:05:57 PM UTC-4, mike wrote:
On 5/1/2014 4:36 PM, Ashton Crusher wrote:

On Thu, 01 May 2014 12:59:51 -0700, mike wrote:



On 5/1/2014 9:39 AM, MLD wrote:



"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



Well, I give each of you half credit. LOL! At a certain RPM, the pump

head (outlet-inlet pressure) and flow rate are both are fairly indept of

the coolant temperature as long as the coolant stays a liquid (normal

condition) when going through the pump. The engine heat raises the

coolant temperature and the pressure (remember this from skool...

PV=nRT), but (and this is a big butt) as long as the pump turns at the

same RPM, the head should stay about the same.



FWIW, here's a decent drawing of a water pump cross-section

http://assets.hemmings.com/story_image/83720-500-0.jpg



A couple of comments--PV=nRT is an equation used in gas flow

calculations not when the fluid is a liquid. Don't understand where you

are coming from. Just for the record, at constant speed the pressure

rise across a centrifugal pump does not remain constant. Typically,

there is a droop (loss of delta P) as the pump flow demand increases.

Relatively insignificant at first but if the flow demand gets large

enough, then the Pump Delta P can drop significantly. Flow demand is

dictated by the characteristics of the the system in question--that is,

how the delta P vs Flow of the system (line losses etc.) matches up with

the delta P vs flow of the pump. Where the two intersect will be the

operating point of the System. The idea is to match them so that the

intersection takes place where the droop in pump deta P is relatively

insensitive to flow demand.

MLD



Riddle me this.

In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is

whatever

the pressure is.

The pump can't put more pressure on the output side than is on the input

side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.



Do pump principles applied to OPEN systems really apply?





Great Question. My original question remains unanswered .... Does the

water pump ADD another 10 to 30 psi internal pressure (as the sources

I originally was looking at claimed) and if it does, how come that

extra pressure, on top of the already existing 12 psi heat pressure,

not cause the cap to blow off from the excess pressure now totaling

from 20 to 40 psi? All I can think is that the pump only adds perhaps

2 to 5 psi and that by the time it "gets" to the cap area, flow

resistance has dissipated it down to 1 or 2 psi and it has ceased to

be a problem. Or maybe the pump only "adds" negative pressure, i.e.

suction at the inlet, or some combo of all that.



It's my contention that the pump can add no pressure unless it has

somewhere to get the water to pump.

It does have somewhere to get the water to pump, it's
through the engine cooling system. And without a pressure
difference, by what physics do you explain the movement of
the coolant through that system?


If it's coming from the closed system, there ain't none available

unless you vaporize some on the source side.

Nonsense, the pump generates pressure just like any pump would.

On Thursday, May 1, 2014 11:06:58 PM UTC-4, wrote:
On Thu, 01 May 2014 17:05:57 -0700, mike wrote:



On 5/1/2014 4:36 PM, Ashton Crusher wrote:

On Thu, 01 May 2014 12:59:51 -0700, mike wrote:



On 5/1/2014 9:39 AM, MLD wrote:



"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



Well, I give each of you half credit. LOL! At a certain RPM, the pump

head (outlet-inlet pressure) and flow rate are both are fairly indept of

the coolant temperature as long as the coolant stays a liquid (normal

condition) when going through the pump. The engine heat raises the

coolant temperature and the pressure (remember this from skool...

PV=nRT), but (and this is a big butt) as long as the pump turns at the

same RPM, the head should stay about the same.



FWIW, here's a decent drawing of a water pump cross-section

http://assets.hemmings.com/story_image/83720-500-0.jpg



A couple of comments--PV=nRT is an equation used in gas flow

calculations not when the fluid is a liquid. Don't understand where you

are coming from. Just for the record, at constant speed the pressure

rise across a centrifugal pump does not remain constant. Typically,

there is a droop (loss of delta P) as the pump flow demand increases.

Relatively insignificant at first but if the flow demand gets large

enough, then the Pump Delta P can drop significantly. Flow demand is

dictated by the characteristics of the the system in question--that is,

how the delta P vs Flow of the system (line losses etc.) matches up with

the delta P vs flow of the pump. Where the two intersect will be the

operating point of the System. The idea is to match them so that the

intersection takes place where the droop in pump deta P is relatively

insensitive to flow demand.

MLD



Riddle me this.

In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is

whatever

the pressure is.

The pump can't put more pressure on the output side than is on the input

side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.



Do pump principles applied to OPEN systems really apply?





Great Question. My original question remains unanswered .... Does the

water pump ADD another 10 to 30 psi internal pressure (as the sources

I originally was looking at claimed) and if it does, how come that

extra pressure, on top of the already existing 12 psi heat pressure,

not cause the cap to blow off from the excess pressure now totaling

from 20 to 40 psi? All I can think is that the pump only adds perhaps

2 to 5 psi and that by the time it "gets" to the cap area, flow

resistance has dissipated it down to 1 or 2 psi and it has ceased to

be a problem. Or maybe the pump only "adds" negative pressure, i.e.

suction at the inlet, or some combo of all that.



It's my contention that the pump can add no pressure unless it has

somewhere to get the water to pump.

If it's coming from the closed system, there ain't none available

unless you vaporize some on the source side.



The water pump can develop mabee a couple of pounds pressure on the

outlet side into a plugged rad with the cap off. With the cap on, with

no air in the system, significantly less. But at best, only a pound or

two. Will running the water pump dead headed cause a temp increase?

Sure, a very small amount. Inconsequential compared to the heat output

of the engine. It will NOT cause a pressure increase in the closed

system.

It will cause a pressure increase on the output side of the pump
versus in the input side.


The increased pressure increases the boiling point of the

coolant. It also helps get and keep entrained air out of the cooling

fluid. The only thing that causes the pressure rize is temperature.

I don't believe that's true. If you measured the system pressure with
respect to the atmosphere right at the pump output, it should be higher
than the pressure measured similarly at the pump input. Both those
points would rise or fall with the temperature of the coolant.



The pressure reduces back to atmospheric when the temperature drops

back to room temperature. Current production vehicles have a "catch

tank" that holds excess coolant if any is forced out to regulate the

pressure, and it is drawn back in on cooldown.

"mike" wrote in message
...
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.

Simply put, it's a pump and there is a restriction on the outlet side. An
engine cooling system isn't a swimming pool with a pump in the middle of it.

On 5/1/2014 7:05 PM, mike wrote:
....

Riddle me this.
In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is
whatever the pressure is.

Fluid flowing or static? (Yes, it makes a difference.) The static
pressure of a stagnant system would be uniform and steady, yes.

The pump can't put more pressure on the output side than is on the input
side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.

Nonense. The pump performs work on the fluid and while one doesn't lose
fluid in a well-maintained automotive cooling system, it is not a
constant volume system, it does have expansion volume thru the overflow
and even water isn't totally incompressible and pressure does go up.

Do pump principles applied to OPEN systems really apply?

Pump principles are principles... There's this thing about
"principles"--if they don't apply, then they aren't.

Great Question. My original question remains unanswered .... Does the
water pump ADD another 10 to 30 psi internal pressure (as the sources
I originally was looking at claimed) and if it does, how come that
extra pressure, on top of the already existing 12 psi heat pressure,
not cause the cap to blow off from the excess pressure now totaling
from 20 to 40 psi? All I can think is that the pump only adds perhaps
2 to 5 psi and that by the time it "gets" to the cap area, flow
resistance has dissipated it down to 1 or 2 psi and it has ceased to
be a problem. Or maybe the pump only "adds" negative pressure, i.e.
suction at the inlet, or some combo of all that.

It's my contention that the pump can add no pressure unless it has
somewhere to get the water to pump.
If it's coming from the closed system, there ain't none available
unless you vaporize some on the source side.

Nonsense, while running (and the thermostat open) it's circulating the
water. It performs mechanical work on the fluid raising the output
pressure in the process which it _must_ do in order to overcome the flow
restrictions and pressure drops along the way before it gets back to the
pump inlet again. Of course the physics of it is that the pump doesn't
"create" pressure--it imparts kinetic energy from the impellers to the
fluid to create velocity therein. It is the resistance to flow that
creates the measured pressure even though it is commonly referred to
"increasing (pressure) head".


The pressure is a variable value from a maximum at the pump outlet to a
minimum at the pump inlet. The pressure at the radiator cap will be
something under the 12 psi or so of the cap release spring or else it
would lift.

So, while your statement above about the closed system and no water
isn't right, the idea that a pump doesn't "create" pressure is correct;
but the pressure is higher at the pump outlet as compared to the inlet
because the input kinetic energy and output velocity thus imparted are
reflected in a higher pressure owing to the design of the pump volutes.
If didn't have a higher pressure at that point, then there'd be no
driving force sufficient to get through the other downstream flow
restrictions. It's analogous to needing voltage to "push" a current
thru a load.

--

On Friday, May 2, 2014 10:33:04 AM UTC-4, Rick wrote:
"mike" wrote in message

...

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.



Simply put, it's a pump and there is a restriction on the outlet side.

So what? Pumps are made to create pressure and force fluids past
resistance in the system. A "restriction" is just like any other
resistance in a piping system, eg elbows, the length of the pipe, etc.

An

engine cooling system isn't a swimming pool with a pump in the middle of it.

Simply put, a pump is always a pump and it can only move
fluid via a pressure difference between the intake and output side.
Otherwise, explain the physics whereby a pump moves fluid without
a pressure differential. You can't, not on this planet.

"trader_4" wrote in message
...
On Friday, May 2, 2014 10:33:04 AM UTC-4, Rick wrote:
"mike" wrote in message

...

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.



Simply put, it's a pump and there is a restriction on the outlet side.

So what? Pumps are made to create pressure and force fluids past
resistance in the system. A "restriction" is just like any other
resistance in a piping system, eg elbows, the length of the pipe, etc.


He asked why the outlet pressure is high, Again, simply put, it's because
there is a restrictin downstream. Obviously the outlet pressure has to be
greater than the inlet pressure.




An

engine cooling system isn't a swimming pool with a pump in the middle of
it.

Simply put, a pump is always a pump and it can only move
fluid via a pressure difference between the intake and output side.
Otherwise, explain the physics whereby a pump moves fluid without
a pressure differential. You can't, not on this planet.

"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

Well, I give each of you half credit. LOL! At a certain RPM, the pump head
(outlet-inlet pressure) and flow rate are both are fairly indept of the
coolant temperature as long as the coolant stays a liquid (normal condition)
when going through the pump. The engine heat raises the coolant temperature
and the pressure (remember this from skool... PV=nRT), but (and this is a
big butt) as long as the pump turns at the same RPM, the head should stay
about the same.

FWIW, here's a decent drawing of a water pump cross-section
http://assets.hemmings.com/story_image/83720-500-0.jpg

A couple of comments--PV=nRT is an equation used in gas flow calculations
not when the fluid is a liquid. Don't understand where you are coming from.

As the engine temperature rises, tiny gas bubbles start to form on the walls of the cooling cavities. The liquid changing to gas causes the pressure to increase. When the fluid is cold, the bubbles are condensed back into liquid right away and there is little pressure increase. As the coolant temp rises, it takes longer for them to condense, the volume of gas increases and the pressure increases.

Just for the record, at constant speed the pressure rise across a
centrifugal pump does not remain constant. Typically, there is a droop
(loss of delta P) as the pump flow demand increases. Relatively
insignificant at first but if the flow demand gets large enough, then the
Pump Delta P can drop significantly. Flow demand is dictated by the
characteristics of the the system in question--that is, how the delta P vs
Flow of the system (line losses etc.) matches up with the delta P vs flow of
the pump. Where the two intersect will be the operating point of the
System. The idea is to match them so that the intersection takes place
where the droop in pump deta P is relatively insensitive to flow demand.
MLD

On 4/30/2014 6:15 PM, MLD wrote:

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. ...

....

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?????
....

What the limit is of how much pressure the water pump can produce is
based on the pump design and I really don't know what those values
typically might be. But, the pressure in the system is controlled by
the pressure cap. There's a very good description at the following link...

http://books.google.com/books?id=xLx...136&lpg=PA136&

dq=does+radiator+cap+control+radiator+pressure&sou rce=bl&ots=--_LIFglKt&

sig=vhm95_RJG8vWT6iJMsaY-3OAGmM&hl=en&sa=X&ei=FdNjU-SuJfP7yAGho4CwCQ&

ved=0CIgBEOgBMAg#v=onepage&

q=does%20radiator%20cap%20control%20radiator%20pre ssure&f=false

--

"dpb" wrote in message ...
On 4/30/2014 6:15 PM, MLD wrote:

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. ...

...

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?????
...

What the limit is of how much pressure the water pump can produce is based
on the pump design and I really don't know what those values typically
might be. But, the pressure in the system is controlled by the pressure
cap. There's a very good description at the following link...

http://books.google.com/books?id=xLx...136&lpg=PA136&

dq=does+radiator+cap+control+radiator+pressure&sou rce=bl&ots=--_LIFglKt&

sig=vhm95_RJG8vWT6iJMsaY-3OAGmM&hl=en&sa=X&ei=FdNjU-SuJfP7yAGho4CwCQ&

ved=0CIgBEOgBMAg#v=onepage&

q=does%20radiator%20cap%20control%20radiator%20pre ssure&f=false

--


30 psi is putting it mildly....

"mike" wrote in message
...
On 5/1/2014 4:46 PM, MLD wrote:

"mike" wrote in message
...
On 5/1/2014 9:39 AM, MLD wrote:

"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

Well, I give each of you half credit. LOL! At a certain RPM, the pump
head (outlet-inlet pressure) and flow rate are both are fairly indept
of
the coolant temperature as long as the coolant stays a liquid (normal
condition) when going through the pump. The engine heat raises the
coolant temperature and the pressure (remember this from skool...
PV=nRT), but (and this is a big butt) as long as the pump turns at the
same RPM, the head should stay about the same.

FWIW, here's a decent drawing of a water pump cross-section
http://assets.hemmings.com/story_image/83720-500-0.jpg

A couple of comments--PV=nRT is an equation used in gas flow
calculations not when the fluid is a liquid. Don't understand where
you
are coming from. Just for the record, at constant speed the pressure
rise across a centrifugal pump does not remain constant. Typically,
there is a droop (loss of delta P) as the pump flow demand increases.
Relatively insignificant at first but if the flow demand gets large
enough, then the Pump Delta P can drop significantly. Flow demand is
dictated by the characteristics of the the system in question--that is,
how the delta P vs Flow of the system (line losses etc.) matches up
with
the delta P vs flow of the pump. Where the two intersect will be the
operating point of the System. The idea is to match them so that the
intersection takes place where the droop in pump deta P is relatively
insensitive to flow demand.
MLD

Riddle me this.
In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is
whatever
the pressure is.
The pump can't put more pressure on the output side than is on the input
side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.

Do pump principles applied to OPEN systems really apply?

Don't understand either of your comments. Could you expand your
explanations so they make some sense?
Do you know what happens if you dead end a centrifugal pump (Zero flow)
while its running?? The discharge pressure might not change but you
better be prepared to see the fluid temperature skyrocket.
You seem to to make a big point out of INCOMPRESSIBLE fluid. Got some
news for you, Ready---fluids, aka liquids, are not INCOMPRESSIBLE!!!
Have you ever heard of "Bulk Modulus", entrained air or compressible
flow as they apply to liquids?
Do you know what would happen to the pressure in a closed system if the
fluid temperature (say water) was increased but the fluid was not able
to expand due to the closed (or fixed) system volume?
Hint: Delta P=(BM) x (Delta V)/V
Clue: Pressure can increase up to the thousands! Want to try and
conduct your own experiment? Close the water inlet shut off valve in
your house. Keep all faucets closed and of course, lock the hot water
tank relief valve so that it doesn't open. Now just crank up the
temperature of your water heater. This ought to seek out your system's
weak link.
MLD


Can't argue with your theory. Problem is that it doesn't apply here
in any significant amount.
If the pressure exceeds the cap pressure, it vents.
The pump didn't add the pressure. In your scenario, the pump added
heat.
So, get back to the topic. In a closed car cooling system under normal
operation
can the pressure on the output side of the pump significantly exceed
the pressure on the input side?

I think we can exclude any vaporization of the liquid leading to excess
pressure. If it did, it would vent and, eventually, there'd be no more
liquid to pump.

But thank you for the clue and the hint and the nitpicking.



Once more---A centrifugal pump--that's what is in your car--the pump
discharge pressure is a function of the pump speed squared. Once the
thermostat opens there is a flow path from pump to radiator back to the pump
inlet. Other than a slight droop in pressure due to the flow demand, the
pressure rise across the pump basically constant. Obviously, no venting
occurs as long as the pressure at the radiator is less then the cap pressure
setting. Pressure at the radiator is established by whatever line loses
there are between the pump discharge and radiator. Venting occurs because
as the coolant temperature increases it's volume will also increase. Why??
Density=Weight/Volume.
Density decreases as temperature increases. Since the weight of the coolant
doesn't change, it's the volume that does.
As the coolant expands, the pressure in the system increases (remember,
trapped volume aka closed system) and when the pressure gets to the cap
setting (won't take long), the cap opens and the fluid goes into the
overflow bottle. If the radiator cap didn't open--whole new
scenario--things would break!!
If this doesn't answer your questions, suggest you do a bit of reading on
your own.
MLD

On Fri, 2 May 2014 00:08:20 -0400, "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.
The difference in pressure across the pump is equal to the difference
in pressure across the radiator. Suction on one side, pressure on the
other. A matter of a few psi with a good rad and the thermostat open.
The pump is not capable of producing very high pressures.. The
pressure on the low side can be up to 5 psi below nominal, and on the
high side as much as 5psi above no

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!!

On Thu, 01 May 2014 17:05:57 -0700, mike wrote:

On 5/1/2014 4:36 PM, Ashton Crusher wrote:
On Thu, 01 May 2014 12:59:51 -0700, mike wrote:

On 5/1/2014 9:39 AM, MLD wrote:

"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

Well, I give each of you half credit. LOL! At a certain RPM, the pump
head (outlet-inlet pressure) and flow rate are both are fairly indept of
the coolant temperature as long as the coolant stays a liquid (normal
condition) when going through the pump. The engine heat raises the
coolant temperature and the pressure (remember this from skool...
PV=nRT), but (and this is a big butt) as long as the pump turns at the
same RPM, the head should stay about the same.

FWIW, here's a decent drawing of a water pump cross-section
http://assets.hemmings.com/story_image/83720-500-0.jpg

A couple of comments--PV=nRT is an equation used in gas flow
calculations not when the fluid is a liquid. Don't understand where you
are coming from. Just for the record, at constant speed the pressure
rise across a centrifugal pump does not remain constant. Typically,
there is a droop (loss of delta P) as the pump flow demand increases.
Relatively insignificant at first but if the flow demand gets large
enough, then the Pump Delta P can drop significantly. Flow demand is
dictated by the characteristics of the the system in question--that is,
how the delta P vs Flow of the system (line losses etc.) matches up with
the delta P vs flow of the pump. Where the two intersect will be the
operating point of the System. The idea is to match them so that the
intersection takes place where the droop in pump deta P is relatively
insensitive to flow demand.
MLD

Riddle me this.
In a CLOSED system FILLED with INCOMPRESSIBLE liquid, the pressure is
whatever
the pressure is.
The pump can't put more pressure on the output side than is on the input
side because it's a CLOSED system FILLED with INCOMPRESSIBLE liquid.

Do pump principles applied to OPEN systems really apply?


Great Question. My original question remains unanswered .... Does the
water pump ADD another 10 to 30 psi internal pressure (as the sources
I originally was looking at claimed) and if it does, how come that
extra pressure, on top of the already existing 12 psi heat pressure,
not cause the cap to blow off from the excess pressure now totaling
from 20 to 40 psi? All I can think is that the pump only adds perhaps
2 to 5 psi and that by the time it "gets" to the cap area, flow
resistance has dissipated it down to 1 or 2 psi and it has ceased to
be a problem. Or maybe the pump only "adds" negative pressure, i.e.
suction at the inlet, or some combo of all that.

It's my contention that the pump can add no pressure unless it has
somewhere to get the water to pump.
If it's coming from the closed system, there ain't none available
unless you vaporize some on the source side.


Your comment makes no sense to me. There is always water at the
inlet to the pump if the system if full of water. You can see the
water moving if you take the cap off, at least on some systems where
it opens into the tank. Clearly the pump is pumping water, therefore
it's getting some to pump and it's certainly not as vapor.

On Fri, 02 May 2014 14:49:18 -0400, wrote:

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!!


Where in the system did you take that 3 psi measurement at?

On Fri, 02 May 2014 14:43:15 -0400, wrote:

On Fri, 2 May 2014 00:08:20 -0400, "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.
The difference in pressure across the pump is equal to the difference
in pressure across the radiator. Suction on one side, pressure on the
other. A matter of a few psi with a good rad and the thermostat open.
The pump is not capable of producing very high pressures.. The
pressure on the low side can be up to 5 psi below nominal, and on the
high side as much as 5psi above no


My little 1.5 hp swimming pool pump, with similar sized centrifugal
impeller to a car, similar sized pipes as a radiator hose, and running
at a couple thousand rpm can easily produce over 25 psi if you shut
down the outlet valve. It seems likely to me that the water pump in a
150 hp car could do the same if the flow was restricted.

"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.

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.

"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.

On Thursday, May 15, 2014 2:41:20 AM UTC-4, 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.

Why does normal coolant temp below 212F equate to using
pure water and a system open to the atmosphere? It can be lower,
depending on factors like the thermostat and where the coolant
temp is being measured. It just can't be higher than 212F.

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

On Thursday, May 15, 2014 12:54:31 PM UTC-4, Guv Bob wrote:
"trader_4" wrote in message ...

On Thursday, May 15, 2014 2:41:20 AM UTC-4, 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.



Why does normal coolant temp below 212F equate to using

pure water and a system open to the atmosphere? It can be lower,

depending on factors like the thermostat and where the coolant

temp is being measured. It just can't be higher than 212F.



Probably a good point, but I'm not sure I understand what you mean.

Maybe I don't understand what you mean. You said:

"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."


A normal mix of water and antifreeze won't boil below 212F.
You could run the car all day at 205F, no? It's the opposite that's
the problem. You can't run a water only coolant, open air, above 212F.
I would think temps below 212F would be normal, depending on the
thermostat, operating conditions and again where the temp is measured.

"trader_4" wrote in message ...
On Thursday, May 15, 2014 2:41:20 AM UTC-4, 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.

Why does normal coolant temp below 212F equate to using
pure water and a system open to the atmosphere? It can be lower,
depending on factors like the thermostat and where the coolant
temp is being measured. It just can't be higher than 212F.

Probably a good point, but I'm not sure I understand what you mean.

"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

"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

"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

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