Injector Pop vs chatter
 

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?

Interesting as I am about to test a set.

Could it be there is a degree of 'bounce' when chattering?

Lookup my post on an electronic pop tester. I give time traces of the fluctuating pressure. It does look like a triangle wave, w/ ~50 psi amplitude. Problem is I found the chattering depends more on how you handle the pump than properties of each injector. On some, they didn't chatter unless I pressed harder on the pump handle.

Thank you Bill I recall reading your post a long time ago but needed direction on how to find it again. But in my observations I seem to have hysteresis initial pop being at least 50 to 120 psi greater than maximum chatter pressure I may have to go to a data logger to capture this. My observations after many repeats seems consistent I would have expected something like your trends.