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Modifications More Plenum Fun with Niksan Ozark

SpindleB

HAM Ranger
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I was thinking about how to add a plenum to an unregulated gun to which I added a regulator. The gun foster fitting is no longer used and I was thinking I could remove it and add a plenum there.

So the question then becomes how? I retasked an inline filter/dryer for the tube. It has m10x1 at both ends. Clean out the material and a you have a 300bar tube. Put a plug in one end and a 90° M10 on the other.

For testing purposes I put a foster fitting on the tube and a open foster on the gun.

It works! But I got ahead myself and don't know if it actually provides any measurable increase in performance. Some idjit forgot to test the gun before he added the plenum.

So, I'll drain the gun, again, put the one way foster back in, test with the chrony, then hook up the plenum, again, test with the chrony.

Sounds like a plan for tomorrow or Tuesday. 20251109_083828.webp20251109_084809.webp
 
Okay, I'm bored, tore it down
No Plenum: 784
With Plenum: 814

Needs a bigger port into the gun.
I used the gun fill probe minus the one way. portion.

Now to reassemble as would be used.
Try just an M10 fitting no foster.
 
*sigh*
Need to use direct fittings no fosters.
Too much restriction through the fosters.
And in my copious and varied fittings collection I dont have the fittings I need.
Ordered via AliExpress.
 
Got the parts for this one and built it up. Been in leak check since Saturday. Forgot about it due to my fun with the FX Boss slug project. Appears to have a very slow leak. 500psi since Saturday.

Will test it out this weekend with the Boss.
20251204_005316.webp20251204_005332.webp20251204_005343.webp
 
Well, at 2500psi on the regulator I'm getting almost 1000fps. Before it was 875fps. Bring the regulator down to 2000psi and it should be solid.

Had to reset everything, the adjustable transfer port was sitting mid scale. So the previous numbers were wrong.
 
Well, at 2500psi on the regulator I'm getting almost 1000fps. Before it was 875fps. Bring the regulator down to 2000psi and it should be solid.

Had to reset everything, the adjustable transfer port was sitting mid scale. So the previous numbers were wrong.
All in the name of science, even if its not super practical looking😆!! Just seeing this thread now....yeah those fosters are the weak (flow) link for sure. I switched out my shop airline fittings (150psi compressor to 1/2in steel pipe on the wall to 3/8 air line reels) and the fitting/coupler upgrade was WILDLY better. They claimed 40% more flow...I believe it!
Anyways...if I get a slug barrel for my ghost some day I may just pop out the reg gauge and thread in a custom 20-ish cc plenum add-on. Mainly want to see how fast i can push chunky slugs, but also want to see if the plenum size is the Ghosts 'weak' link. Well done sir, keep us updated👍
 
All in the name of science, even if its not super practical looking😆!! Just seeing this thread now....yeah those fosters are the weak (flow) link for sure. I switched out my shop airline fittings (150psi compressor to 1/2in steel pipe on the wall to 3/8 air line reels) and the fitting/coupler upgrade was WILDLY better. They claimed 40% more flow...I believe it!
Anyways...if I get a slug barrel for my ghost some day I may just pop out the reg gauge and thread in a custom 20-ish cc plenum add-on. Mainly want to see how fast i can push chunky slugs, but also want to see if the plenum size is the Ghosts 'weak' link. Well done sir, keep us updated👍
The foster fitting has fairly deep thread and the fittings are 4000psi. The bottle is filled from the regulator so it was superfluous. The interior hole is probably 6-7mm as opposed to the gauge hole of maybe less than 2mm. Using the gauge hole wasnt an option. Definitely ugly but it works. Only issue is it sticks out there and could get torn off. which means I will probably pull it all off and just plug that hole. 10x1mm fittings are not terribly stout.

I did notice the bark was significantly sharper with the plenum so it is pushing a lot more air down the barrel.
 

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