Paintball

[Jackson]

I'm trying to tune my spyder to shoot at lower pressures. Currently I've removed the venturi from the bolt and have it shooting a consistent 270 fps at around 550 psi. I'd like to get this a bit lower.

My question is, what combo of springs will net the lowest usable pressure? I have two valve springs (stock and a lighter one) and a 5 piece main spring kit.

[brycelarson]

Originally Posted by Jackson

I'm trying to tune my spyder to shoot at lower pressures. Currently I've removed the venturi from the bolt and have it shooting a consistent 270 fps at around 550 psi. I'd like to get this a bit lower.

My question is, what combo of springs will net the lowest usable pressure? I have two valve springs (stock and a lighter one) and a 5 piece main spring kit.

sorry to sidetrack your thread - but why do you want it to go lower?

now for my answers - to get low you prob need to reduce the valve spring weight - that'll allow your valve to open wider - therefore allowing the same volume of air through at a lower pressure.

[Jackson]

Originally Posted by brycelarson

sorry to sidetrack your thread - but why do you want it to go lower?

now for my answers - to get low you prob need to reduce the valve spring weight - that'll allow your valve to open wider - therefore allowing the same volume of air through at a lower pressure.

For one, it's quieter. Two, gotta put that Stabilizer to some good use. And three, bragging rights/just because I can. I'm a tinkerer, what else am I going to do?

That's what I thought. I just don't have a chrono and don't feel like spending an hour at the field chrono messing with it going in the wrong direction with the springs.

[brycelarson]

Originally Posted by Jackson

And three, bragging rights/just because I can. I'm a tinkerer, what else am I going to do?

yeah, I buy that.

think about low pressure this way - approximately the same number of air molecules need to reach the ball. The lower pressure the gas the larger the passage that needs to open to allow the same volume of uncompressed air to reach the breech of the gun. So, anywhere there's a restriction on the flow of gas will require a higher pressure to get the ball moving.

It's been a while since I've working on my Spyder clone - but basic idea is that you're going to need a valve that opens wider to run low pressure than high. This means you should look at the soft valve spring, any if you feel up to it, see if you can open up the passage through the valve after the cup seal - maybe you can get a bit more flow through there.

If you do achieve super low pressure the problem that you're going to run into is getting the gun to re-cock. Since the design uses the air pressure to return the bolt / hammer - at some point you'll turn it into a single action gun that you have to manually re-cock between shots. There's a thread somewhere on here about getting spyders to shoot at 177fps for use in Japan. Just reducing pressure was possible - but was goofing up the function of the gun.

[Jackson]

Originally Posted by brycelarson

yeah, I buy that.

think about low pressure this way - approximately the same number of air molecules need to reach the ball. The lower pressure the gas the larger the passage that needs to open to allow the same volume of uncompressed air to reach the breech of the gun. So, anywhere there's a restriction on the flow of gas will require a higher pressure to get the ball moving.

It's been a while since I've working on my Spyder clone - but basic idea is that you're going to need a valve that opens wider to run low pressure than high. This means you should look at the soft valve spring, any if you feel up to it, see if you can open up the passage through the valve after the cup seal - maybe you can get a bit more flow through there.

If you do achieve super low pressure the problem that you're going to run into is getting the gun to re-cock. Since the design uses the air pressure to return the bolt / hammer - at some point you'll turn it into a single action gun that you have to manually re-cock between shots. There's a thread somewhere on here about getting spyders to shoot at 177fps for use in Japan. Just reducing pressure was possible - but was goofing up the function of the gun.

I've bored out an extra valve a bit to try to increase flow. Haven't tested it yet. Also modified a valve pin with an extra blow back slot to try to increase airflow to recock. I'll try combining those two along with the lighter valve spring and see what drive spring I can use. Thanks for the help.

[aqua_scummm]

A lot of spyder modders make LP chambers just to keep the flow rate up. I'm not doubting the dark magical powers of a stab, but it is nice to have a volume of pre-regulaetd air ready.

[ta2maki]

Originally Posted by Jackson

I've bored out an extra valve a bit to try to increase flow. Haven't tested it yet. Also modified a valve pin with an extra blow back slot to try to increase airflow to recock. I'll try combining those two along with the lighter valve spring and see what drive spring I can use. Thanks for the help.

You should only add to the recock slot if you have recock issues and are able to sacrifice velocity. If you direct too much air for recocking, you won't be able to get useable velocity.

Here's my bored out spyder valve and pin. My spyder will cycle down to 200psi. I have it set at 450psi for reliable operation, which also is the top of the sweetspot pressure.

[TheAznInvazn]

I modded my spyder to work at around 300 psi consistantly by doing all the mods in my sig >.<

havent messed with the valve pin spring though, but I do like my spyder much more after doing all these mods :tup

[sunfisher89]

I"m currently working on a "sleeper" spyder. I'm using a classic spyder and I'm going to try and make it fireable at the lowest pressure possible. Originally that wasn't the plan...but it seems all the aftermarket parts for these guns are made for LP operation. I'm currently waiting on a pile of parts to come in, this LPC just happens to be one of them:

hehehe

I'm probably going to be doing one of those updated regularly updated project threads soon enough.

I do have a suggestion though. I made a pump spyder a few years ago. It order to make a new valve pin that would eliminate blowback I had to rig up a "lathe." I took a corded drill and put it in a vise, upside down. Turn it on and you have yourself a rotating rod for a perfectly symmetrical valve pin. I put the cut to length rod in the drill. Then I used a dremel grinding wheel to get it roughly down to specs. After that I used sandpaper to smooth out and finish it up. It worked great, nearly eliminated all blow back

Anyways, you could use the same process to make yourself a new high flow valve pin.

[TheAznInvazn]

Interesting idea...

I wasn't really done with my pin either. Was going to grind it down more in a few areas.