Gutting or Removing the Thermostat

[staticpat]

Even the mazdamotorsports tech section recommends this.

Originally Posted by mazdaspeed

Water Pump
Water Pump/Thermostat
If you are using a stock (cast-iron) water pump, we recommend "gutting" the stock thermostat, leaving just the thermostat casing. Because some "restriction" is helpful, generally removing the thermostat is not as effective as using a gutted thermostat or restrictor. It is also important to plug the thermostat housing's water bypass. This can be done very easily by tapping the hole (1/2" pipe tap) and installing a plug