Mike... the water restriction is used to regulate your engine temperature finitely if you choose to do so.. nitro and the corresponding engine temperature will effect your engine performance... an overheat can cause engine damage as the engine leans out and quits... intently you may want to gain a flow meter and keep statistics on engine temperatures, and other test factors like ambient air, air density, humidity, water temperature and beyond... its all what you want to look into it... gauging along the way , the performance in your testing.... good luck...
