I was playing around with some older injectors and had noticed that the initial pop pressure varies somewhat in relation to chatter pressure. For example one injector popped at 1960 psi but chatters at 1870. Another one pops at 1990 but chatters at 1940. It's the difference in pop vs chatter pressure that I was wondering about. Sometime it's roughly 50 psi and others shows up to 120 psi difference. Is this anything to be concerned about or what have others observed?