Velocity too low

[Bilbo]

I just took my Xtra out for a scenario game in MD. I loved the reliability of it (not a chopped ball or jam all day long). Of course, I felt very outgunned by the the kajillion-balls-a-minute superguns, but I held my own. And it made me aim more and plan my shots.
Anyway, even with the velocity adjuster all the way up, the best I could manage was 220 fps. As the day warmed up, I got around 230, but still way below the field speed of 285.
I understand a new main spring can be put in to help with this.
Two questions:
1) what is different about the "upgraded" spring? Is it longer, shorter, stiffer, what? And how does this affect velocity?
2) Is there anything that can be done to the existing spring to improve velocity? Can I trim it, stretch it, or whatever? Part of the reason I ask is so I can try it while waiting to get a new spring. And, frankly, part of it is because I hate paying 10 bucks for a little spring.

[kidonfire]

1) When you fire the gun, the hammer hits the valve pin(because the spring pushes it), which opens the valve and lets the air in. what the spring does is controls how long the valve stay's open, letting air in. the stiffer spring will hit the pin harder keeping it open for longer, and letting more air in, giving you more velocity. a lighter spring will hit the pin softer letting less air in.

2)I don't think you can make it stronger. The best thing to do would be to get a spring kit, which gives you 3 main springs(soft, med, heavy) so you can fine tune your velocity.

[Theheroguy]

a spring kit and this (http://www.alamocitypb.com/MANUFACTPAGES/accesspix/spydervbk.html)

[bracer028]

that velocity thing is useless

just use a soft valve spring and a hard main spring and ur velocity will jump to 300

[Hob Hayward]

Yeah. Though, I'd play around with springs first. Try switching to a light valve with a medium main spring. That should keep recoil from increasing, and also increase velocity by increasing dwell (dwell is the length of time that the valve stays open) .

[Bilbo]

A follow-up post.
Today I played walk on at another field. I didn't have a chance to buy any springs, but saw on another board about how someone put washers on the spring guide to increase the tension. Well, I figured I had nothing to lose, so I put 3 washers on there.
Well, today my velocity topped out at 286. A huge leap from the 230 I was getting. It was a warmer day, but not that much.
On a side note, I also learned today what a difference decent paint makes. I had a bunch of very old bargain paint and decided to burn it up today. Well, it spun around in corkscrews (really a sight to see) and went this way and that. On top of that, my faithful spider had its first major jam when one broke in the chamber and the bolt jammed on the shell fragments. Had to disassemble the marker and push the bolt out with a dowel. Then I tried some newer paint (actually also not top-notch, but better), and what a difference. Range and accuracy really jumped.

Anyway, thanks to all those who answered my post.