As others mentioned, you'll kill your EEPROM pretty quickly that way, but to answer your questions...
Ben1234:
Does anyone know how long that additional time will be?
That entirely depends on your code. If the rest of your loop is an assignment statement, a mere nano seconds. If the rest of your loop is a few hundred floating point calculations, then it might take a while.
Is there a function that I can use to test the time?
millis(). You're better off using that than delay() anyway.