Pressure gauge for the engine coolant system

[The Lovely Boyo]

Hello,

I'm going to fit a better temperature gauge to the engine (lots of info available).

AND... I want to fit a pressure gauge as well. My theory being that as soon as air (or any gas for that matter) gets into the cooling system the pressure will start to drop (air being much more compressible than liquid).

Or would the pressure just stay at 0.9bar and not see any difference on the gauge????? I'm thinking of the stories of pressurised cooling systems even though the head has gone and there's no coolant left.

The normal system runs on 0.9bar so a guage reading 0 - 2 bar should be ample (assuming this theory has merit)

When cold it will read zero. As the temp increases so should the pressure. Both gauges should then stabilise at about 90deg temp and 0.9 bar pressure.


What do you guys think???

[plumb bob]

From a plumbing/heating background, a pressurised heating system will still show pressure even with air in the system, although when the air is released the pressure will drop.

There may also be a point when the surf system would be at negetive pressure, ie when cooled from a long run.

[Woodzie]

I would have thought that as soon as the guage shows the pressure increase it will be too late , as the rad cap is only 0.9bar

[plumb bob]

I would have thought that as soon as the guage shows the pressure increase it will be too late , as the rad cap is only 0.9bar

You could find a guage that goes to 1 bar max?

[gwh200]

Hello,

I'm going to fit a better temperature gauge to the engine (lots of info available).

AND... I want to fit a pressure gauge as well. My theory being that as soon as air (or any gas for that matter) gets into the cooling system the pressure will start to drop (air being much more compressible than liquid).

Or would the pressure just stay at 0.9bar and not see any difference on the gauge????? I'm thinking of the stories of pressurised cooling systems even though the head has gone and there's no coolant left.

The normal system runs on 0.9bar so a guage reading 0 - 2 bar should be ample (assuming this theory has merit)

When cold it will read zero. As the temp increases so should the pressure. Both gauges should then stabilise at about 90deg temp and 0.9 bar pressure.


What do you guys think???

by bernouillis eqn p1v1t1=p2v2t2

p=pressure
v=volume
t=temp

as the system is pressurised it causes the coolant to obviously boil at a higher temp if you manage to cool that volume (which is at a lower temp per pressure)thereby prohibiting boiling,you will achieve a "false" pressure
reading.p1v1t1=p2t2v2 is really useful for working out molar masses it says that two volumes of gas both different,but both at the same pressure volume and temperature contain avagdros number of molecules.assuming the volume is the same equal and constant(it wont be as it is cooled then heated but lets pretend)then you cn assume a constant pressure (which again you cant but lets pretend for now)
the theory says that the pressure should be the same,but as heating occurs volume temp and pressure all change.it would work if you had an average reading frommultiple points in the hot/cold cycle(and i do believe apache is your man for that)as for air in the system,this is a gas and whilst liquid is virtually icompressible gas is very compressible,but!!!!!

it will still(to a point )exhibit behaviour according to p1 v1 t1=p2 v2 t2
to make a failsafe you would probably need a flow detector or end of flow device,

just a thought

[surfenstein]

by bernouillis eqn p1v1t1=p2v2t2

p=pressure
v=volume
t=temp

as the system is pressurised it causes the coolant to obviously boil at a higher temp if you manage to cool that volume (which is at a lower temp per pressure)thereby prohibiting boiling,you will achieve a "false" pressure
reading.p1v1t1=p2t2v2 is really useful for working out molar masses it says that two volumes of gas both different,but both at the same pressure volume and temperature contain avagdros number of molecules.assuming the volume is the same equal and constant(it wont be as it is cooled then heated but lets pretend)then you cn assume a constant pressure (which again you cant but lets pretend for now)
the theory says that the pressure should be the same,but as heating occurs volume temp and pressure all change.it would work if you had an average reading frommultiple points in the hot/cold cycle(and i do believe apache is your man for that)as for air in the system,this is a gas and whilst liquid is virtually icompressible gas is very compressible,but!!!!!

it will still(to a point )exhibit behaviour according to p1 v1 t1=p2 v2 t2
to make a failsafe you would probably need a flow detector or end of flow device,

just a thought

feck are you sure you werent dr frankenstein in another life.i was just about to say the exact same thing.

[gwh200]

feck are you sure you werent dr frankenstein in another life.

it really easy to do.its all been written and worked out years ago,and all you have to do is add the numbers in and hey presto,
besides its only theory,you dudes make stuff and cut stuff and you can call vince and he knows what colour a 1st gen interior should be and you call you and you just made a monster that feeds on small children and you call tony n and he just knows everything about surfs and you call mattf and hes just made a supercomputer and you call on everyone and they all made something,i cant do that

now thats dr frankenstein,


damm i feel llike typing tonite

[surfenstein]

it really easy to do.its all been written and worked out years ago,and all you have to do is add the numbers in and hey presto,
besides its only theory,you dudes make stuff and cut stuff and you can call vince and he knows what colour a 1st gen interior should be and you call you and you just made a monster that feeds on small children and you call tony n and he just knows everything about surfs and you call mattf and hes just made a supercomputer and you call on everyone and they all made something,i cant do that

now thats dr frankenstein,


damm i feel llike typing tonite

yea but you know everything there is to know about pooh,you never know one of us may just call you.i did say may.

[gwh200]

yea but you know everything there is to know about pooh,you never know one of us may just call you.i did say may.

mate i only deal with it on an industrial disposal level,if you are suggeting what i think then no!!!!

im not going anywhere near woodzies ass ever again

[stormforce]

mate i only deal with it on an industrial disposal level,if you are suggeting what i think then no!!!!

im not going anywhere near woodzies ass ever again

you may want to rephrase that

[surfenstein]

im not going anywhere near woodzies ass ever again

bwahahahahahahahahahahahahahah aha.

[Woodzie]

Industrail disposal........all i had was a slight case of wind









BULLIES.......


I'm off

[surfenstein]

Industrail disposal........all i had was a slight case of wind









BULLIES.......


I'm off

aw come on mate your the only human being that i know of that can fart as bad as a dog.

[stormforce]

aw come on mate your the only human being that i know of that can fart as bad as a dog.

from what i have read not even a dog is that bad

[surfenstein]

from what i have read not even a dog is that bad

rich im not kidding if you had been there you would of suffocated and if that didnt kill ya then you would of died of laughter afterwards.