Power Plenum ~ Taipan Veteran

I haven’t measured valve port but will next time I’m in there. Side note; the refresh rate (shot to shot plenum recharge) on this setup is about 15 seconds. Shooting it faster gives a much poorer SD and ES.

It's around 10s for mine.i took the little fill limiter screw out of the top of my Huma reg though. That is with the Huma right? Have you chrono'd any heavy slugs with it yet? Would love to know what the max FPE is in your .25
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Bah, this has been a slow marathon getting this one setup. I bored out my brass TP to 5.53mm, thought it was all good and had air dumping down the barrel. Had to resurface a flat on the face to get it sealing again. 
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Anyways, I got all of 10fps out of that mod from where it was before for 959fps max. I had dropped my reg pressure down to around 142bar prior and tested a new spring and bushing. Cocking is like cutting warm butter, but with the larger port I earned a benefit of using even lighter tension. When I shoot the monsters, it sounds like 400fps when it's actually 900-915
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Hoping it's accurate. Dumping rain here again tomorrow, but I'm a soldier so I gotta get out and test it
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Really like what you’re doing there. Great work!!

I’m running the factory regulator. It is good as long as your set speed to max plateau differential is less than 3.5%. 

This .25, with reg set to 150+ bar (I’m currently at 142 bar) w/ a stronger hammer spring, I would estimate, could achieve 75 FPE. W/slugs about 71 FPE. With Hybrid slugs it would get a few more FPE (maybe 73) as they are more forgiving through a choke. 
 
@zx10wall, that's good to know! 142bar seems like a decent compromise for power and shot count too. I'm using the Huma for testing, but I like this factory reg a lot and want to use it once I figure out the final configuration. I might wind up making an adapter for my reg tester so I can fine tune them better, those 12 bolts man.. my right forearm is going to be diesel soon turning these things! lol

Next up for me - testing over 150bar. Might even go 160-170 to gather data..


 
Alright I'm going to call this power tune job good now! Cranked my reg up to 160bar, which is smoking the Monsters out at 970fps 
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I'm going to leave it up there to test at paper, because I'm too damned curious on how those and the NSAs will shoot with this barrel.

Holy smokes!! You’ve got that dude screaming 😱 now. Way to go. Interested in results on paper now. 
 
Thanks, it's pretty close to where I wanted it now, but I still need to plan for testing with different valve springs soon.

Also, I have a slight concern with the valve seat at higher pressures. I'm thinking hard about making a new one with a slightly larger seat in a slightly more robust design. It's holding up though, I just dislike not having spare parts. I can keep it light with titanium, but it still might turn out a tad heavier than factory (which will surely change some the dynamics requiring testing with different springs).

Anyways, I'll probably just make a couple now and shoot with the factory pin until it breaks and deal with it afterwards. I haven't made any valve pins yet, but I have a pretty good idea of a press fit design (barbed at the seat end, and maybe even flanged at the back of the seat as a retainer, and then using the end of the Ti pin for the spring guide portion instead of the composite material 🤔)

Has anyone heard of these valve pins breaking under higher pressures? I get the feeing that us Taipan modders are few and far between though!
 
Thanks, it's pretty close to where I wanted it now, but I still need to plan for testing with different valve springs soon.

Also, I have a slight concern with the valve seat at higher pressures. I'm thinking hard about making a new one with a slightly larger seat in a slightly more robust design. It's holding up though, I just dislike not having spare parts. I can keep it light with titanium, but it still might turn out a tad heavier than factory (which will surely change some the dynamics requiring testing with different springs).

Anyways, I'll probably just make a couple now and shoot with the factory pin until it breaks and deal with it afterwards. I haven't made any valve pins yet, but I have a pretty good idea of a press fit design (barbed at the seat end, and maybe even flanged at the back of the seat as a retainer, and then using the end of the Ti pin for the spring guide portion instead of the composite material 🤔)

Has anyone heard of these valve pins breaking under higher pressures? I get the feeing that us Taipan modders are few and far between though!



Mine broke on my .25 cal long back in October way before I added the power plenum. I made a new one out of Ertalyte TX , Pet-P. I also made a new valve pin out of O1 tool steel. I have about 2000 rounds on the new valve with no issues. I made mine a little bigger than the factory one with no decline in velocity.


 
Mine broke at the tip of the pin laterally. The top half basically sheered off. I just made mine to be press fit. I am not a machinist and don't have a lathe. I made it on my drill press with some improvised tools. The material I used is suppose to be a happy medium between Delrin and Peek. Better impact resistance but easier to get to seal. If I was more technically advanced I would post a pic of it. It is a very basic design. 
 
I measured the plenum volume in the Ernest plenum extensions and the Huma reg plenum tube. The extensions are 20cc's each, and the Huma cylinder comes in around 18cc's.

I should have taken off the aluminum piece that goes into the block to measure its volume as well, but I already put it back together.. so take it or leave it! :p
 
Received my papy_yosh lefty biathlon lever and my cheek-piece yesterday. These, as well as the mag holders, are quality pieces. They enhance an otherwise great package. 

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Agreed! I got mine yesterday too. I was kind of worried about how well the magazine holders would attach to the barrel, but man he did a great job with the design 👍
 
Hi everyone my name Mohamed from Egypt

I have taipan veteran standard 0.22, and I really need to install power plenum for shooting heavy slug 25 : 33 grain, I have some questions

1- what is the recommended reg pressure should I adjust after installing plenum ( noted factory set about 135 bar ), should I increase or decrease the pressure ?? 

2- is it recommended to modify the valve port ( increase the diameter ), if it does what is the recommended diameter ?

3- as my information the power plenum add more air volume capacity, so can I fill beyond 250 bar, I want to know how this plenum increase shot count ???

4- should I buy a modified heavy hammer spring ( I want a link for sale ) ??

5- should I replace the return spring with another weak one ???

Thanks very much






 
Hi everyone my name Mohamed from Egypt

I have taipan veteran standard 0.22, and I really need to install power plenum for shooting heavy slug 25 : 33 grain, I have some questions

1- what is the recommended reg pressure should I adjust after installing plenum ( noted factory set about 135 bar ), should I increase or decrease the pressure ?? 

2- is it recommended to modify the valve port ( increase the diameter ), if it does what is the recommended diameter ?

3- as my information the power plenum add more air volume capacity, so can I fill beyond 250 bar, I want to know how this plenum increase shot count ???

4- should I buy a modified heavy hammer spring ( I want a link for sale ) ??

5- should I replace the return spring with another weak one ???

Thanks very much






1) Install the power plenum and test. 

2) I wouldn't say it's recommended but it does help. If you do it wrong though, you will be up a creek without a paddle. Don't know dimensions. 

3) No, do not fill over the manufacturers max pressure.

4) Pull your spring out and measure it. Springs are readily available on Amazon (music wire works well)

5) No, the factory return spring is already on the weak side. 

Sorry, typo below. Power tune wire size should be .48 not .048

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Thanks alot for you

1- Why I shouldn't recommend not filling beyond 250 bar, I will already add an extra air capacity, how do this plenum increase the shot count while I fill 250 bar also like before ???

2- could you please give me the exact link for hammer spring, I searched on Amazon, didn't find it ?????


1) You shouldn't fill beyond what the manufacturer recommends because that is a gamble you don't want to take! The added plenum will get you more shots if you kept the FPE the same. This is because you can lower your regulator's set point with the extra volume of regulated air on tap and continue to get the same power. You won't have to hit the valve stem as hard and you will shoot down to a lower pressure. 1+1 equals 2

2) https://www.amazon.com/dp/B005KSVVM8?psc=1&ref=ppx_pop_dt_b_product_details ~ quit skipping leg days. Leg work is good for you 😆. These are stainless and do work very well.