I have just installed the coolant separation kit, I have not closed the valves yet as I have just changed the coolant in the system and I am waiting to get it balanced out and all the air in the system evacuated.

I remembered that some people advocated that this system be non pressurized by means of a separate reservoir open to atmospheric pressure. My thought on this was that the IC would then be subject to variations of greater pressure from outside the cooler due to the supercharger pressure rising and falling. This would exert external crushing pressures on the cooler leading to fatigue and failure. The difference in the forces would be greater than the difference of the forces if the IC had its own internal forces due to heat expansion in a closed system.

The cooler in any case ends up like a concertina being squashed and expanding constantly by internal and external pressures. With the open system these differences will be greater and lead to earlier failure due to fatigue stresses on the seams most probably.

Water really does not compress at these pressures but the hoses in the system expand and contract so the cooler flexes a small amount. The water does expand and contract due to the heating/cooling cycles so the cooler and hoses expand and contract as a result.

My conclusion was that the closed separated system is probably best in keeping the pressure differences inside and outside the cooler lower. The OEM system would have higher pressures in the cooler due to the higher temperature of the coolant. The SC is not often running at the high boost pressures, well for me anyways.

Am I on the right track or am I wrong?

 

When you shut the car off the the pressure would still be present on the inside. What's radiator pressure, 16psi?

*** for tat I say.

I think the root cause of failure is poor construction.

 

Pressure inside what and which setup?

Obviously the construction is not up to snuff but helping the situation by reducing stress has got to help.

The pressure cap is set to blow at 16psi plus/minus 2psi.

 

I have been no pressure Woody since this cooling thing began. Please remember that the I/C varies from -14psi to plus 16 or what ever. That is a differential of 30 psi compression to about zero at full boost with your 16 psi rad. I have zero pressure so I go from -14 to plus 16differential, which is the same SWING if you are following my drift.

I have only plus or minus 16 psi approximately while you go from 30 psi to zero pressure differential. I like mine better as I have half the stress - - divided between + and - pressures. You go from -14 with +16 tank pressure ( 30 psi difference ) to +16 to +16 ( about zero difference). As soon as you lift off the boost you go to full 30# difference instantly, working the tank more.

I plan to do a flow and leak test on a members I/C that failed, so as to gather more understandings. I believe it may be a galvantic problem. More to follow. Enjoy Woody

 

Where is -14 coming from?
That is a darn good low pressure.

With the reservoir cap having a minimum low tolerance of 14psi I am sure that a normal radiator system will not get to that pressure or the the fluid would soon be low. 10-12psi maybe as the cap will be just out of the normal pressure range.

My original statement said that I was not considering max boost, frankly where on the roads can you do that and not get unwanted attention from the local constabulary? The cooler would last a long time if you lost your license. Also I was making the statement that the separated system was better in my mind.

For those that do not know the system is separated at the normal working temperature of the engine and therefore the separated system will cool down and lower the pressure inside it due to the water reducing its volume. From then on the IC system will only warm up from the use of the SC, ignoring radiant and conducted heat from the engine and the coolant will be cooled by the IC radiator. What pressure it will reach will certainly be lower than the engine coolant due to the lower temperature reached. At least one would hope so or the separated system is wasted money. When cool the system could have the rubber pipes collapse slightly to balance the IC coolant pressure to the ambient air pressure.

 

As the separated IC heats pressure rises, pick a pressure you like I assumed the max of 16#.
( When you shut the car off the the pressure would still be present on the inside. What's radiator pressure, 16psi? - earlier posting ).

The -14psi is the number when your off the throttle, i.e. -25 -28 inches of mercury, I idle at -20+ inches.

So you can move the numbers, but I have 0 psig on the IC circuit. and thus lower differential pressure. The highest pressure difference is wide open throttle ( boost is high ) throttle, and IC tank pressure. In my analysis, I assumed the worst for most of the cars - NON ISOLATED IC running 16 psig and Idle or off throttle vacuum ( partial pressure ) which approaches 30 psig differential.

Worst, the pressure varies greatly in time, it can be zero differential to + 30 psig on the I/C many times in seconds in spirited driving. Again, I have the pressure differential that varies from + 15 psig and zero psig between the air and water circuits.

I still put forward the idea of electrolysis weaking the walls / joints due to chemicals and or currents thru the liquid circuit - charging current, starter current etc. I have water pump lube and conditioner added to my 25% ANTIFREEZE SOLUTION in the I/C curcuit.

HUMMMMM, I will have to see if my water has a Ph of 7.0 or not????
Weekend ENJOY. Woody