Valve Identification

[alpha_q_up23]

Hey guys, I recently got a mag with a what I thought was a lv 7. Today I was looking through some extra parts and found an extra lv 10 assembly so I figured I'd just pop it on and when I went to unscrew the tip of the power tube, and the whole power tube unscrewed as well, I was just curious as to what kind of valve this is, as I have not seen this before.

Thanks, and here are some pics of said valve.

[Nobody]

More than likely it is a lvl7 that was cut in the powertube so that you could put in a powertube spacer. Otherwise, as long as you can put in the L10 bolt, its all good.

[Cyco-Dude]

just a lvl 7 valve. either the weld was cut like nobody said, or it broke. i have a classic valve that i can unscrew the power tube as well.

[vintage]

i've got one that does that. can be interesting if your powertube tip is extra tight.

[alpha_q_up23]

Yeah I can get the lv7 tip off, just was a bit curious about it cause I had never seen that before, thanks again.

[alpha_q_up23]

Also quick question, could I use an efficiency insert and would it be just a drop in? Or would I need to send it to luke or someone to have something done?

[Cyco-Dude]

i think it just drops in. they are for co2, aren't they?

[athomas]

The inserts are for any gas. They reduce the volume of the chamber and causes it to operate at a higher pressure. It creates more of a pop when fired such that the volume of gas exits faster because the higher pressure is less affected by the retriction in the air path through the bolt.

[Cyco-Dude]

i don't see how that would improve efficiency at all for hpa. pressure and volume are inversely proportional, with the amount of gas, the gas constant, and temperature on the other end of the ideal gas law. those variables are assumed constant...lower volume with higher pressure, or lower pressure with higher volume, you still end up propelling the paintball to 280 fps. the only benefit i see of higher operating pressure is a faster cycling rate, which let's face it, you don't need unless you're going for a bps speed record. the drawbacks in my mind would be increased sound, the bolt action being harder on paint (due to the faster cycling), and not shooting as deep into the tank due to the higher pressure required.

i do not think the efficiency insert does anything beneficial under hpa.

[athomas]

i don't see how that would improve efficiency at all for hpa. pressure and volume are inversely proportional, with the amount of gas, the gas constant, and temperature on the other end of the ideal gas law. those variables are assumed constant...lower volume with higher pressure, or lower pressure with higher volume, you still end up propelling the paintball to 280 fps. the only benefit i see of higher operating pressure is a faster cycling rate, which let's face it, you don't need unless you're going for a bps speed record. the drawbacks in my mind would be increased sound, the bolt action being harder on paint (due to the faster cycling), and not shooting as deep into the tank due to the higher pressure required.

i do not think the efficiency insert does anything beneficial under hpa.

Normally, higher pressure and lower volume is equal to lower pressure and higher volume. In order to maintain maximum efficiency, you need to have all the air available instantaneously without restriction for both cases. In the case of any valve or air line with something restricting the flow, you can get more air (volume x pressure combination) out faster using a higher pressure than you can using a lower pressure. The lower volume would also cause more of the air in the chamber to be released during the impulse. This allows you to get closer to making the appropriate amount of required air instantaneously available than if you used a low pressure and allowed it to slowly flow out behind the ball. Since the higher pressure and the lower volume will exhaust itself sooner, you also have less wasted air trailing behind the ball that has already left the barrel as well. A lower pressure impulse couldn't keep up with the ball past a certain distance as it travelled down the barrel, because of the slower air discharge, but the returning bolt wouldn't be able to close off the flow because more air would still be available in the chamber. The higher pressure air would have a shorter duration impulse of air behind the ball and because of the lower volume, more would be used to propel the ball and less would be wasted trailing the ball.

A higher pressure chamber with less volume would actually slow down the rate of fire. It would take longer to recharge the chamber back to a higher pressure than it would to recharge to a lower pressure due to the finished pressure differential being less with the high pressure chamber than with the lower pressure chamber. The lower pressure differential would slow the charge rate as the chamber finished its top off of the regulated air.

[Spider-TW]

Also, the higher chamber pressure gets harder on paint, both in the bolt action and gas impingement on the ball. IIRC, Hill's numbers were in the 5-10% improvement range with HPA. CO2 improvements are significant, like 30-40%, depending on high you are willing to go. A 12g automag can really benefit from an insert or other devolumizing.