spyder valve spring help

[headman]

What does changing the valve spring do to a spyder? Why would you make it lighter vs. heavier if you did change it?

[Lord Delta]

Changing the spring does a couple things.
1) The stiffer the spring the higher you can get your velocity (to a certain limit, can't go crazy w/ a super stiff spring) Its like when you use your velocity adjuster on your marker, you are compressing or stretching the spring. Compressing it is like using a stiffer spring and increases your velocity a bit.

2) People often make their markers shoot at a lower operating pressure (most stock blow back markers operate around 800psi which is the pressure the co2 comes out of the tank at)

Lowering the operating pressure has several advantages, but I won't go into that here, check other threads for that. When they lower the pressure they need to replace their main spring with a lighter tension spring. In a blowback marker co2 is used to fire the paintball and recock the bolt. The bolt is pushed back against your main spring. If the spring isn't replaced often the co2 bled off from firing the paintball won't be able to recock the bolt because the low operating pressure can't overcome the stiff spring.

This is kinda long, and probably kinda confusing. If you don't understand it, or I missed what you were asking let me know and I'll try to clarify.