They open based on vacuum and the secondary springs. The lighter the spring, the lower the vacuum signal (RPM) they open. It's not really RPM based, it's vacuum based, but the two are related. You could get a GOPRO and stick under the hood. Aren't they pretty affordable now?
Haha, thats not a half bad idea.
I pulled my springs but the color at the tip has worn off. I tried to match them up with the pics of the different springs, counting the rings, and they look to be either the purple or short yellow. Purple is mid point, yellow is light. Anyways, I guess what Im saying is that when regular driving, the paper clip didnt move. Only when I stabbed it at 2500 in first.
