Pressurized Water System

[Mutley]

I am looking into building a pressurized water system for my car would like to hear how some you guys have done it. What are somethings I should look out for?  -M

[maguromic]

How much pressure do you want to run? Tony

[Racerboy]

Just a few questions

What engine, and what class
What type of water punp (electrical or mechanical)
Radiator or water tank (and what size tank)

[Mutley]

I am going to be running in C comp coupe with a SBC.  I want to use a radiator with a header tank and run 35-40 lbs of pressure. -M

[krusty]

 Take a look here    http://www.crracing.com/custom-built-products/pressurized-cooling-systems   and here    http://www.crracing.com/tech/cooling-installation-details/using-pressurized-colling-system  for information on high-pressure cooling systems as used in many professional series' engines. Remember that your radiator, accumulator, and hoses/fittings need to be rated to withstand the pressure you decide to run at. I have used this system in both Cup cars and LSR and it works very well.    vic

[maguromic]

To add to Vic’s comments, you wont find a cap much higher than 30 pounds, and then your only option is to build a system like Vic suggests.  One of the things you want to keep in mind us the fin count on the radiator
 
In my experience the more fin count per square inch the better.  I have found that 17-23 fin count, with 17 being the minimum I would use works.  Without the extra fin count for support, anything lower you run the risk of core degradation. On our RMR we will be running closer to 50 pounds and on my neighbors GC Firebird, we will be running a radiator with 200 fins per inch and pressurizing to 40 pounds.

If you set up the system properly you could use different water pressure as part of your strategy to tune the motor for optimal performance.  Tony

[Mutley]

Vic and Tony, thank you for the information.    It looks like its a little more involved than I thought. But then what isn't? -M

[kiwi belly tank]

Mutley, another way to it is to put a small radiator in a water tank, pressure the rad but not the tank. Gives you gobbs of cooling capacity.
  Sid.

[Jonny Hotnuts]

A sealed system will develop pressure when the water heats up and is metered by the PSI rating of the cap. If you want 30 psi, put a 30 psi cap on it and the water pressure in the system will make that a few seconds after the water temp reaches just over 100 degrees and starts to expand.

I have a 5 gallon air tank I use for my coolant tank with a 15 psi cap, no radiator and it pressurizes itself just fine.

I know some peeps will say I am wrong, and it is necessary to have the restriction of the radiator core to develop head pressure (and it will make a few pounds depending on the pump and restriction) the system does NOT need a radiator to develop its operating pressure. When the water heats up it will pressurize beyond the head pressure of the pump and wont care if there is a radiator, tank or other.

If for whatever reason you want to pre pressurize your system.....you would have to use pressurized water or you will be introducing air in the system.

~JH

[manta22]

A sealed system will develop pressure when the water heats up and is metered by the PSI rating of the cap. If you want 30 psi, put a 30 psi cap on it and the water pressure in the system will make that a few seconds after the water temp reaches just over 100 degrees and starts to expand.

I have a 5 gallon air tank I use for my coolant tank with a 15 psi cap, no radiator and it pressurizes itself just fine.

I know some peeps will say I am wrong, and it is necessary to have the restriction of the radiator core to develop head pressure (and it will make a few pounds depending on the pump and restriction) the system does NOT need a radiator to develop its operating pressure. When the water heats up it will pressurize beyond the head pressure of the pump and wont care if there is a radiator, tank or other.

If for whatever reason you want to pre pressurize your system.....you would have to use pressurized water or you will be introducing air in the system.

~JH

JH;

You're not exactly wrong but your understanding is a bit incomplete; true, the coolant will develop a pressure in the cooling system that will be relieved by the pressure cap if it is allowed to reach a high enough temperature-- however, the thing about pressurizing the block & heads by the water pump is true, but that pressure is over & above the pressure in the radiator and pump inlet. So even higher pressure will be developed by the back pressure of a restriction.

Regards,   Neil  Tucson, AZ

[hotrod]

If for whatever reason you want to pre pressurize your system.....you would have to use pressurized water or you will be introducing air in the system.

Not necessarily, if you use an air over water accumulator with a bladder, connected to the cooling system by a small diameter tubing. The system can be pressurized by airing up the bladder in the accumulator, but there is on water flow in the small diameter pressurization tube, so the accumulator never sees the high temperature water in the cooling system. Also if the system does burp a little water the make up water that the accumulator will push into the system will be cooler water than the circulating water helping to cool things off.

Basically the same configuration as the oil pressure accumulators like used in the accusump systems.

http://www.cantonracingproducts.com/cgi-bin/commerce.cgi?search=action&category=2410

Larry