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Old 06-01-2012, 12:01 PM #43
van457
 
 
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stock g4 sharpie mod rod protrustion.

Last edited by van457 : 06-01-2012 at 01:11 PM. Reason: misspelling
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Old 06-01-2012, 12:04 PM #44
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pic showing finished area of metal removed (silver area no anno)to allow better fitting oring. almost zero friction with these bolts now.I chuck these bolts up in a drill press and spin/polish with mequires mag polish or sim. metal polish and 0000 steel wool for a smoother finish.

Last edited by van457 : 06-07-2012 at 06:20 PM. Reason: Added polish info
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Old 06-01-2012, 12:12 PM #45
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Better pic of g3 bolt head shows stem tail reduction, on my gun this only gets "mechanical" dwell back to stock spacing when bolt is fully forward due to moving bolt stop forward to squeeze bolt stop oring. When you move bolt stop forward you also move inside (small) stem oring forward, thus you have to take some of bolt stem off to achieve same dwell.( distance of open space between small oring and bolt stem when bolt fully forward).

Last edited by van457 : 06-07-2012 at 04:53 PM.
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Old 06-01-2012, 01:49 PM #46
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I wish those pictures were in focus!
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Old 06-01-2012, 02:23 PM #47
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It's my thread so I suppose I can do what I want right? Even present non DP stuff.

Here's the Drone DX bolt and valve. The design is very similar to what DP uses for their spool valve. I think the MD design allows for smoother air flow since the air has to flow around a cylinder rather than around a mushroom shaped part and then into the bolt which probably creates more turbulent air flow. The completely squared off valve face in the Drone creates a low pressure zone right in front of the valve which may help in retracting the bolt. I know that the Drone bolt returns back about twice as fast as it goes forward which helps with efficiency. A cone may hurt in that case. The top 3/4" of a sharpie cap is about all that could be used due to much closer clearances between the bolt and valve. There will have to be a 3/32" 90 degree edge around the cone, but I think that 80% of the turbulent air can be dealt with.



You may not be able to see it, but my bolt and valve have been x-ringed. This Drone already runs at 95 psi at 280 fps. It is my hope that once broken in the x-rings will shave off 5 more psi.
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Last edited by rkenders : 06-01-2012 at 03:17 PM.
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Old 06-01-2012, 03:01 PM #48
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van457,

Regarding increasing your dump chamber size to lower operating pressure, I have an idea that should have much better air flow than your barbed fittings and reg extender. Both of those ideas require air flow through small ports which means the air can't move quickly. A better way to increase dump chamber size and would require no modification of the gun body would be to tap the back cap to 1/2 NPT threads and then drill several holes inside that area through the back cap. This would provide a high flow expansion dump chamber that could keep up with the spool valve. Thread a short section of brass pipe onto the back cap. The added volume can be "tuned" by putting washers inside the short pipe section to take up space if it is too large. Obviously the spool valve can flow air only so fast. Make sure the added dump chamber can match that flow rate. I don't think your hoses and the 1/8" internal air passage can flow that fast. So in my opinion while it may help, it isn't ideal since it can't flow air quickly enough. HPR's while having varying flow rates are not designed to keep up with the spool valve. Anyway my idea provides the needed flow rates. The bolt requires a certain minimum amount of pressure in order to cycle reliably and to overcome it's own resistance to moving. Flow rate and friction define how low the operating pressure can be. I think going with x-rings will help with the friction significantly. It may be possible to get the G4 operating reliably at 100-110 psi. Hmmm! I may need to keep my G4 and NOT sell it after all!!! This is a challenge I rather look forward to.

More observations...
The Drone DX has a dump chamber that is easily twice as large as the dump chamber in the G4. I'm certain that this extra volume is a significant reason why the DX runs at half the pressure of the G4. Also, the DX bolt moves very easily. Much easier than the G4 bolt. The Techt bolt moves about as easily as the DX bolt so I think this is the better platform for an ultra low pressure G4. Also the Techt back cap extends out the back of the gun a little and is essentially hollow which increases the size of the dump chamber some. This of course allows for 10-20 psi reduced operating pressures. The Techt back cap is also more like a cylinder with a flat end which would allow for a larger port to meet or exceed the flow rate of the spool valve. OK OK! I'm NOT selling my G4!
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Last edited by rkenders : 06-01-2012 at 03:35 PM.
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Old 06-01-2012, 04:39 PM #49
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Yes, they do flow fast, especially with 2 lines and the c.p. regs. I've attached a full 68/4500 and flipped on raps with no bolt in gun to see, it'll empty a tank quick.You have to realize 2- 1/8" I.D. lines plus air inlet inside gun.That's more flow area than hole size in reg piston.This dropped operating pressure with lines alone without shortening bolt stem. But, I agree that it would be better to go with a bigger can on rear of gun for alot of reason's: Simpler- air lines don't look good-could leak or snag on something-labor intensive-additional cost beyond cost of bolt-and They may be other reasons i can't think of right now. The main reason I never went with a bigger air can is I don't have a machine shop.With the lines you just get parts and do it.Well maybe not that simple

Last edited by van457 : 06-01-2012 at 04:51 PM.
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Old 06-01-2012, 06:29 PM #50
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If i am correct about the xrings, does that not cause first shot drop off as well???
I have seen this on alot of videos where people did the xring mod, and if i am not mistaken Boomer in Macdev forum tried this and took them off because of this very same reason... and from what i seen it is real bad first shot drop off.

Xring mod being done on the drones of course...
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Old 06-02-2012, 03:47 AM #51
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Originally Posted by Shru View Post
If i am correct about the xrings, does that not cause first shot drop off as well???
I have seen this on alot of videos where people did the xring mod, and if i am not mistaken Boomer in Macdev forum tried this and took them off because of this very same reason... and from what i seen it is real bad first shot drop off.

Xring mod being done on the drones of course...
I read Boomer's comments too and wondered about it. As soon as I x-ring'd my Drone I took it outside and chrono'd on my Virtue Clock. I had ABS set to 4 for the stock o-rings and with the x-rings my first shot was hot so I set it to 3. After that my first shot or 10th shot were the same. I repeated the test several times by waiting a minute between strings of 10-20 shots fired at about 1bps. I wonder if Boomer had some marginal x-rings. The Drone is kind of picky about the o-rings you use and will suffer from significant bolt stick if the o-rings aren't just right. The bolt will pass the flick test just fine, but still not fire consistently. Anyway, one of my Drones has always been perfect and the other was a royal pain due to bolt stick issues until I finally replaced all the dynamic o-rings. After that it worked well. I just x-ring'd that Drone and I'll get to use it for real on Sunday. I'll see then if they cause me issues or not.
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Old 06-02-2012, 03:48 AM #52
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Originally Posted by van457 View Post
Yes, they do flow fast, especially with 2 lines and the c.p. regs. I've attached a full 68/4500 and flipped on raps with no bolt in gun to see, it'll empty a tank quick.You have to realize 2- 1/8" I.D. lines plus air inlet inside gun.That's more flow area than hole size in reg piston.This dropped operating pressure with lines alone without shortening bolt stem. But, I agree that it would be better to go with a bigger can on rear of gun for alot of reason's: Simpler- air lines don't look good-could leak or snag on something-labor intensive-additional cost beyond cost of bolt-and They may be other reasons i can't think of right now. The main reason I never went with a bigger air can is I don't have a machine shop.With the lines you just get parts and do it.Well maybe not that simple
It's in a lot of ways because of your input here that I have changed my mind about selling my G4. Thanks! I wasn't really wanting to sell it.

On the subject of flow rates...
The spool valve has got to flow as fast as possible since it's open for a very short time. The HPR however has easily twice as long to recharge the dump chamber so it's flow rate doesn't need to be any where near as high as the spool valve. Did you have any improvement with the CP regulator over the stock regulator? The DP reg is average on consistency and so I replaced mine for that reason. I found a PE Ego reg for $20 that was much better. On a related thought, your sharpie cap mod stream lines the air flow, but it also appears to restrict the amount of space the air has to travel in. Have you tried a much shorter piece of sharpie cap? I am wondering if the cap really needs to go all the way to the bolt face or if a 3/4" long piece would work just as well.
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Last edited by rkenders : 06-02-2012 at 04:07 AM.
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Old 06-02-2012, 04:40 AM #53
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Before trying to make a bolt mod for my G4 thanks to yours, I wanted to find a soft to see how the flow is in function of the bolt guide. I have gound Flow Illustrator (available here).

I tried this with three bolt guide : stock G4 back cap ; a bolf guide inspired by the Geo ; and a bold guide inspired by the Geo and the Clone

It result in these pictures :



I think that the best bolt guide would be like this on the right.

I'll try to design one and to machine it to verify
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Old 06-02-2012, 10:23 AM #54
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rkenders, I don't believe sharpie cap restricts the flow due to two things.#1- 15 psi drop in pressure to reach same fps, this is obvious as more efficient.#2- At smaller restriction near base of sharpie cap (were it hits stem), your pressure will be HIGHER here than at front of cap due to less volume at this area . What is happening is gas is RAPIDLY going past base of cap to displace LOWER pressure at front of cap.

Last edited by van457 : 06-02-2012 at 03:35 PM.
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Old 06-02-2012, 01:55 PM #55
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Has anybody run an actual efficiency test on modifying the tail of the L7 bolt, or is it an assumption that is being made because of the immediate velocity boost and allowing the gun to operate at a lower pressure?

The velocity will go up because the restriction from the flow path is being reduced - the tail sticking into the flow path when popping out of the bolt stop to fire acts like a needle valve - having it further away from the orifice reduces the restriction. But while shortening the tail means it opens sooner and further, it also means that it takes longer to shut the flow off when the bolt retracts, which typically has a negative impact on efficiency. Probably a good way to lower your OP if you are a low pressure chaser, but I'm honestly a bit leery about it improving efficiency unless you have an aftermarket board capable of lowering the dwell more to help offset the added time to shut the valve off.

Not that it can't potentially help, just food for thought...
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Old 06-02-2012, 03:02 PM #56
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Have never run efficency test. I've never run out of air, so as long as it's reasonable thats ok.I don't go on the field with a case of paint on my back.Well, I mean I don't expect to shoot a case of paint in one game.the only time i trimmed stem on bolt was to compensate for moving bolt stop forward thus making bolt fully forward space the same.

Last edited by van457 : 06-02-2012 at 03:12 PM.
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Old 06-02-2012, 03:43 PM #57
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Yoda900, One thing to remember about gun pressure is lower pressure is quieter, I know you know this. But, if I can take a shot at somebody (I play rec/woods ball) and they don't know it until their hit becuse they never heard a shot, BIG advantage.
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Old 06-05-2012, 06:40 PM #58
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Yoda,

It's my opinion that shaving a little off the bolt tail wont make the gun more efficient. Admittedly I haven't done the mod yet myself. It will lower the guns operating pressure since air flow will be less restricted. However that lower pressure is only going to come if the dump chamber is enlarged. The G3/G4 has a smallish dump chamber which is why it needs the pressures it does. The Techt bolt expands the dump chamber by hollowing out the back cap and as a result gives you a few PSI. Also the Techt bolt moves a lot easier than the stock bolt. I'm sure that helps the need for higher pressures a little too. Truely Van457's mod needs the added dump space and the bolt mod to work well.
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Old 06-06-2012, 08:28 AM #59
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Originally Posted by rkenders View Post
Yoda,

It's my opinion that shaving a little off the bolt tail wont make the gun more efficient. Admittedly I haven't done the mod yet myself. It will lower the guns operating pressure since air flow will be less restricted. However that lower pressure is only going to come if the dump chamber is enlarged. The G3/G4 has a smallish dump chamber which is why it needs the pressures it does. The Techt bolt expands the dump chamber by hollowing out the back cap and as a result gives you a few PSI. Also the Techt bolt moves a lot easier than the stock bolt. I'm sure that helps the need for higher pressures a little too. Truely Van457's mod needs the added dump space and the bolt mod to work well.
It is your opinion and i Fully respect that, but this is based on my own experience last weekend.
Son shot a modded g3 last weekend, he got 1000 shots off of a 3700 psi fill on a 49/4500 tank...
His marker was running at an 11 dwell as well, I could lower the dwell and get a few more shots or have a full fill and get another 100-200 shots possibly... so if he actually had a full fill on a 49/4500 tank, he in reality would have gotten between 1100-1200 shots, on a 68/4500 fill a much greater number...
So in my experience, And my bolts are actually modded, that it has helped out alot in efficiency, Unless you know anyone else that would probably get close to 1200 shots on a 49/4500 tank, I would consider them numbers pretty damn good...especially for a dump valve spoolie..
I believe a Clone VX which is supposed to be one of the more efficient spoolie markers is only getting around 1400 shots on a 68/4500 fill and that is a well broken in VX at that..
And i actually owned a vx as well and can confirm that number as well.

On one test that i know of, on a 1000 psi test running at a dwell of 10 on a modded g3, the shot count was 450 something... the test was done as well on a 11 dwell and 12 dwell and of course the shot count went down, this was on a 1000 psi test...
so if we even multiply that or give and take some, you should be able to achieve at least or around 1600 shots on a full fill of a 68/4500 tank..

These are not my opinions but facts, does not matter if anyone believes it or not, Unless anyone wants to paypal me the cash to buy medium to highend paint, pay for my gas and air...I will be more than happy to shoot paint on video and show it to you...
It does not matter to me if anyone here mods the bolt or not, I own 2 g3 markers and justicexd has his g3 modded as well, I reap the rewards of it and I just wanted to share what his mod actually did to the marker...
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Old 06-06-2012, 09:19 AM #60
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What bolts do you run, and what mods do you do to them? On my g4, If I had known that techt bolt stuck into breach opening where ball drops down, I would have waited for yoda's bolt. But my g3's and two son's g3's rock.If you shoot some good paint like evil out of a good barrel like a lurker etc., you can own anybody.Um, yea. looks like techt bolt with stem mod?

Last edited by van457 : 06-06-2012 at 10:07 AM. Reason: added info
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Old 06-06-2012, 10:39 AM #61
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posted on previous page what i was talking about
pen shows on the bolt where it was shaved slightly...
I run only on g3 markers, I don't own a g4 personally, these are true facts of what i get, so it also does improve effeciency without sacrifing sound signature either or consistancy...
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Old 06-06-2012, 10:45 AM #62
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Cool. Thanks.
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Old 06-06-2012, 11:04 AM #63
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Shru-How much did you shave off your bolt?
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