Posted by: Vampyr on December 22, 2003 at 21:29:39

I'd really get a rocket and try it... without boring the valve seat.... I need to try to find LPCD's article on setting up the rocket, the only mirror I knew of is gone (Autococker.net has been down for awhile and I have not heard from the admin in a long time.) The rocket is a good valve and on a stock '98 it will get you to about 215 PSI without additional mods. Give it a shot, they're what... $35 or so... The trick in LPCDs method was to set the opening in the rocket, and grind off the excess shaft that extended beyond the hat to help how the valve closes. Make sure you are happy with the performance of the Rocket before you consider boring the valve seat. You may want to get a second valve incase they ever go out of production.... A black anno'd Jackel body runs what... 135 to 160 ish... been awhile since I looked. Those are already 2K specs. The reason that increasing volume off the front block on a '98 doesn't help much is the restriction of the banjo bolt. The 2k+ bodies have much largerbanjos which by the diagram shows much better volume directly upstream from the valve seat. Now a quick run down on why that area is important... Look at a garden hose, for a given diameter, the longer the hose the greater the friction loses (flow rate). the shorter the length of the restriction, the better the flow. granted diameter of the orifice has a lot to do with it as well. the next biggest restriction is at the valve. the area between the cupseal and the body, and the area between the cupseal and the valve body. this is probably one of the worst restrictions in the gun. Not much you can do about it without major work and a custom valve design. the final transfer hole from the valve up to the bolt is actually quite large, but it might be opened up a bit but you will have to rethread the set screw for holding the valve body (in the case of the rocket it is strictly a plug.) The rocket has much larger holes in the body than the transfer hole, and it also has a reduced radius where the holes are and a full set of 4 holes for better transfer flow. This means the main things to open up are the ASA to body internals and the valve seat. I don't really know which helps the most. On a '98 opening up to 2K+ banjo gets alot more air where you need it. Lastly would be the transfer hole, I believe you already know that the stock bolt is extremely high flow.... Just a quick check on why you want the volume there, where it can really flow behind the valve. You are basically opening a port to atmosphere. (behind the ball) you want to pressurize it a bit to try to get constant acceleration the entire length of the barrel. to do that you want a constant pressure on the ball. This really isn't going to happen. The pressure upstream of the valve is going to drop. the trick is to try to minimize the drop for the duration that the valve is open. Or more appropriately the pressure drop behind the ball, to do that you need a volume much greater than your barrel volume (Enough so that the barrel volume is insignificant) and a flow path atleast as big if not bigger. Reality dictates that this is an unreasonable thing to do. So now you know what the goal is, you need to do whatever is possible to come closer to that perfect solution. The closer you can get to that perfect situation, the lower the pressure required to operate on. Hmm, I wonder if you can bore more metal out towards the valve seat, but leave the seat intact. Also if you measure the outside diameter of the valve spring and the ID of the housing it sits in to figure out how far off center it could get, then subtract twice the thickness of the spring wire, you could safely bore the valve seat out to that diameter and not have any worry of loosing the spring into the front block. : : You comments about the second hole in the ASA for increased Reg flow gave me a thought. : : If the need for extra volume is actually behind the valve AND in front of the restriction resultiing from the valve spring seat, then Why not port out the ASA hole and Enlarge the ASA so it adds VOLUME between the reg and body? Basically an extended ASA and with a larger internal/external diameter? : : All those holes go into the body in FRONT of the restriction for the valve spring seat. That's why it won't work....

Follow Ups: Found it... Vampyr 21:36:58 12/22/03 (1) Good thought Dale "Head_Hunters" DuPont 09:20:35 12/23/03 (0) Post a Followup Show your name as: DefaultRealnameBothNickname E-Mail address (eg: joeschmoe@aol.com): Show your e-mail address? DefaultYesNo Your Password: Don't have a password? CLICK HERE - Forgot your password? CLICK HERE Subject: Subject:Message: : I'd really get a rocket and try it... without boring the valve seat.... I need to try to find LPCD's article on setting up the rocket, the only mirror I knew of is gone (Autococker.net has been down for awhile and I have not heard from the admin in a long time.) : The rocket is a good valve and on a stock '98 it will get you to about 215 PSI without additional mods. Give it a shot, they're what... $35 or so... The trick in LPCDs method was to set the opening in the rocket, and grind off the excess shaft that extended beyond the hat to help how the valve closes. Make sure you are happy with the performance of the Rocket before you consider boring the valve seat. You may want to get a second valve incase they ever go out of production.... A black anno'd Jackel body runs what... 135 to 160 ish... been awhile since I looked. Those are already 2K specs. : The reason that increasing volume off the front block on a '98 doesn't help much is the restriction of the banjo bolt. The 2k+ bodies have much largerbanjos which by the diagram shows much better volume directly upstream from the valve seat. : Now a quick run down on why that area is important... Look at a garden hose, for a given diameter, the longer the hose the greater the friction loses (flow rate). the shorter the length of the restriction, the better the flow. granted diameter of the orifice has a lot to do with it as well. the next biggest restriction is at the valve. the area between the cupseal and the body, and the area between the cupseal and the valve body. this is probably one of the worst restrictions in the gun. Not much you can do about it without major work and a custom valve design. the final transfer hole from the valve up to the bolt is actually quite large, but it might be opened up a bit but you will have to rethread the set screw for holding the valve body (in the case of the rocket it is strictly a plug.) The rocket has much larger holes in the body than the transfer hole, and it also has a reduced radius where the holes are and a full set of 4 holes for better transfer flow. : This means the main things to open up are the ASA to body internals and the valve seat. I don't really know which helps the most. On a '98 opening up to 2K+ banjo gets alot more air where you need it. Lastly would be the transfer hole, I believe you already know that the stock bolt is extremely high flow.... : : Just a quick check on why you want the volume there, where it can really flow behind the valve. You are basically opening a port to atmosphere. (behind the ball) you want to pressurize it a bit to try to get constant acceleration the entire length of the barrel. to do that you want a constant pressure on the ball. This really isn't going to happen. The pressure upstream of the valve is going to drop. the trick is to try to minimize the drop for the duration that the valve is open. Or more appropriately the pressure drop behind the ball, to do that you need a volume much greater than your barrel volume (Enough so that the barrel volume is insignificant) and a flow path atleast as big if not bigger. Reality dictates that this is an unreasonable thing to do. So now you know what the goal is, you need to do whatever is possible to come closer to that perfect solution. The closer you can get to that perfect situation, the lower the pressure required to operate on. : Hmm, I wonder if you can bore more metal out towards the valve seat, but leave the seat intact. Also if you measure the outside diameter of the valve spring and the ID of the housing it sits in to figure out how far off center it could get, then subtract twice the thickness of the spring wire, you could safely bore the valve seat out to that diameter and not have any worry of loosing the spring into the front block. : : : : You comments about the second hole in the ASA for increased Reg flow gave me a thought. : : : If the need for extra volume is actually behind the valve AND in front of the restriction resultiing from the valve spring seat, then Why not port out the ASA hole and Enlarge the ASA so it adds VOLUME between the reg and body? Basically an extended ASA and with a larger internal/external diameter? : : : : All those holes go into the body in FRONT of the restriction for the valve spring seat. That's why it won't work.... [ Follow Ups ] [ Post Followup ] [ WARPIG Tech Talk - Autococker / Minicocker ]