Spooler

Coolant pressure has been a topic of discussion. I can tell you by watching my Emtron display that the coolant pressure varies on when the thermostat opens and closes. My car naturally has a max coolant pressure of 25psi when using 12psi of boost at 8k rpms. It does the exact same thing at 23psi of boost. The pressure does vary if the thermostat is open or closed. When the car is cold I can see 19psi just cruising around. Once the thermostat opens, it drops down to 12-15 psi of coolant pressure. After a run, it is 12psi of pressure. I know one other person that drilled his thermostat, basically removed the guts, and his are only 12psi but he has no thermostat. That's fine for a drag car but not good for a streetcar. That's one of the things you need to do if you have copper headgaskets. They don't like high coolant pressure. We really need a coolant by-pass like I run on my 04.5 Dodge Dually with a 5.9 diesel to limit coolant pressure. Back in the old days they would clip the water pump fins to help with this. That's old school stuff.