How many lbs radiator pressure cap is optimal?

[vector1]

i talked to howe because i had a car show up with a ruined radiator (howe brand) and they recommended a 22-24 lb. cap. the radiator actually had the cooling tubes expanded so no air could flow through. i asked them how this could happen and he explained that when an air bubble is ran through them it is real easy to do. i should have asked how but he didn't elaborate. the radiator had a 16 lb. cap installed and the puke hose was ran to the top of the catch can which is prob why the head gasket was leaking and blowing the coolant and filling the system with air, because the coolant was being expelled and not recovered. by the way my jbl was doing the same thing because the catch can was also hooked up incorrectly by the po, blowing coolant and not recovering which led to a leaking head gasket.

the cooling system i am currently running on the jbl is using a 22# cap. the puke tube is running to the bottom of a catch can with the catch can filled 1/2 full. the top of the catch can is prob inline with the top coolant hose. i am running a stewart high flow 180 thermostat with three drilled holes purchased from speedway already drilled. there is no air in the system, none, nada, zilch. when the system heats up the coolant is pushed into the catch can and when it cools down the coolant is drawn back into the main system. after the system cools i can take the cap off and it is filled 100% with coolant. this is on an all aluminum engine so i would think if the pressure was too much it would show on this setup.

i think unless you have air in the system because of hydraulics the cap is going to let go no matter what. my top tube is inline with the top of the engine, so its either going to contain quite a bit of air in the top hose, engine, and radiator, or 100% coolant, i went with the latter.

i had an oem 195 thermostat with two holes installed and the temp would fluctuate too much, i like the stewart high flow 180 much better for holding temp and should work well for racing.

hth