Please post Impact X/MKII Power Plenum .30 cal performance.

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The reason that exist the collar on Michal plenum from Poland is to fit at all generations of impact . On Mki first second and third generation the thread of the valve housing is smaller diameter . Since the mkii came in the market Fx change the valve housing with bigger diameter thread ( to fit in the bigger plenum tube 23mm) .

when I order the power plenum from Michal he asked me which generation impact I have . My impact is the x third generation . So I assume that the collar exist in Mkii as well but with different dimensions than mine. ( bigger) 

When I order later the newest valve housing with integrated valve seat ( not removable vs) I made in the lathe smaller diameter the tread area of valve housing to fit in Michals collar . ( I could not wait long time for a new collar from Poland ) 
 
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I believe FX made some of their parts thicker because the have more to lose than a small business... But I think Michal's is plenty safe and well made.
Click to expand...

Just measured the PP OD, it is 33mm as well, just like the Polish plenum.

When the wall thickness would have been 2mm less, (which I can hardly believe, as the wall thickness of the FX PP is an estimated 4mm) even then that does not give even close to an extra 17cc.

Volume of a tube being 100mm in length and 30mm OD and 26mm ID only displaces 8.8cc..... 

The PP is even shorter inside..... 

I think we can conclude that there is definitely not a significant difference in volume between the PP and the Polish variant. 

Too bad (well, actually not😜) my gun is in one piece again, otherwise I would have calculated the displacement of the PP including the valve housing. 
 
Upvote 0
I believe FX made some of their parts thicker because the have more to lose than a small business... But I think Michal's is plenty safe and well made.
Click to expand...

Just measured the PP OD, it is 33mm as well, just like the Polish plenum.

When the wall thickness would have been 2mm less, (which I can hardly believe, as the wall thickness of the FX PP is an estimated 4mm) even then that does not give even close to an extra 17cc.

Volume of a tube being 100mm in length and 30mm OD and 26mm ID only displaces 8.8cc..... 

The PP is even shorter inside..... 

I think we can conclude that there is definitely not a significant difference in volume between the PP and the Polish variant. 

Too bad (well, actually not
1f61c.svg
) my gun is in one piece again, otherwise I would have calculated the displacement of the PP including the valve housing.
Click to expand...

So basically the main difference in a stock gun, polish vs fx would be the hammer spring giving the extra power. Which I think the 357 impact comes with a stronger hammer spring so in lower caliber it might have the same energy as a mk2 with polish plenum..... or I could be completely wrong....80% chance I’m wrong. 
 
Upvote 0
I believe FX made some of their parts thicker because the have more to lose than a small business... But I think Michal's is plenty safe and well made.
Click to expand...

Just measured the PP OD, it is 33mm as well, just like the Polish plenum.

When the wall thickness would have been 2mm less, (which I can hardly believe, as the wall thickness of the FX PP is an estimated 4mm) even then that does not give even close to an extra 17cc.

Volume of a tube being 100mm in length and 30mm OD and 26mm ID only displaces 8.8cc..... 

The PP is even shorter inside..... 

I think we can conclude that there is definitely not a significant difference in volume between the PP and the Polish variant. 

Too bad (well, actually not😜) my gun is in one piece again, otherwise I would have calculated the displacement of the PP including the valve housing.
Click to expand...


Even if they are the same the one from Poland is a much better deal at $150 USD delivered.
 
Upvote 0
I believe FX made some of their parts thicker because the have more to lose than a small business... But I think Michal's is plenty safe and well made.
Click to expand...

Just measured the PP OD, it is 33mm as well, just like the Polish plenum.

When the wall thickness would have been 2mm less, (which I can hardly believe, as the wall thickness of the FX PP is an estimated 4mm) even then that does not give even close to an extra 17cc.

Volume of a tube being 100mm in length and 30mm OD and 26mm ID only displaces 8.8cc..... 

The PP is even shorter inside..... 

I think we can conclude that there is definitely not a significant difference in volume between the PP and the Polish variant. 

Too bad (well, actually not
1f61c.svg
) my gun is in one piece again, otherwise I would have calculated the displacement of the PP including the valve housing.
Click to expand...

So basically the main difference in a stock gun, polish vs fx would be the hammer spring giving the extra power. Which I think the 357 impact comes with a stronger hammer spring so in lower caliber it might have the same energy as a mk2 with polish plenum..... or I could be completely wrong....80% chance I’m wrong.
Click to expand...

Another big difference is that the valve spring is inside the Polish plenum, while the FX PP valve spring is at the valve adjuster.

I am running mine with a superlight VS, and the old style rubber ball. I can even use it without VS at all, and just the rubber ball.

The old, longer hammerspring is actually softer than the shorter PP spring....

To get more speed, the slider can be given a bit more preload at "max" setting, (play removed, and a bit extra preload) as long as you can keep on rotating the HST adjuster.
 
Upvote 0
I believe FX made some of their parts thicker because the have more to lose than a small business... But I think Michal's is plenty safe and well made.
Click to expand...

Just measured the PP OD, it is 33mm as well, just like the Polish plenum.

When the wall thickness would have been 2mm less, (which I can hardly believe, as the wall thickness of the FX PP is an estimated 4mm) even then that does not give even close to an extra 17cc.

Volume of a tube being 100mm in length and 30mm OD and 26mm ID only displaces 8.8cc..... 

The PP is even shorter inside..... 

I think we can conclude that there is definitely not a significant difference in volume between the PP and the Polish variant. 

Too bad (well, actually not
1f61c.svg
) my gun is in one piece again, otherwise I would have calculated the displacement of the PP including the valve housing.
Click to expand...


Even if they are the same the one from Poland is a much better deal at $150 USD delivered.
Click to expand...

Original PP is 139€ here in EU, or 150USD. Also, the original kit contains far more parts, new valve stem, new hammer, new hammerspring, new adjuster. These parts can be combined with the old parts, so that means more possibilities.

Not trying to stirr the pot, but IMHO the original one seems like the best deal to me, especially if the displacement is about the same.
 
Upvote 0
Original PP is 139€ here in EU, or 150USD. Also, the original kit contains far more parts, new valve stem, new hammer, new hammerspring, new adjuster. These parts can be combined with the old parts, so that means more possibilities.

Not trying to stirr the pot, but IMHO the original one seems like the best deal to me, especially if the displacement is about the same.
Click to expand...

I haven't purchased an FX PP, I saw some people posting $300 as the price. I prefer the old setup but I trim the long spring and close one end to seat atop the coupler before the valve.
 
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I kinda think we got off track here on the OP's original post. I for one would like to see the .30 Impact with PP performance compared to the Impact X without PP (doesn't matter if its FX or Polish). What I'd especially like to see are the efficiency numbers... All you need is the pellet or slug weight, starting and ending bottle pressure, bottle volume, number of shots, and average FPS per shot. I ran the numbers from Giles video when the PP was first released and came up with about 1.49 FPE/cu-in. For reference, the .30 Vulcan2 I was tuning came to 1.52 FPE/cu-in.

PCP Efficiency Calculator
 
Upvote 0
I kinda think we got off track here on the OP's original post. I for one would like to see the .30 Impact with PP performance compared to the Impact X without PP (doesn't matter if its FX or Polish). What I'd especially like to see are the efficiency numbers... All you need is the pellet or slug weight, starting and ending bottle pressure, bottle volume, number of shots, and average FPS per shot. I ran the numbers from Giles video when the PP was first released and came up with about 1.49 FPE/cu-in. For reference, the .30 Vulcan2 I was tuning came to 1.52 FPE/cu-in.

PCP Efficiency Calculator
Click to expand...

Ok C'cut i ran a 40 shot string across the chrony.

240-173bar (could be 174 but i called it 173)

108 or so on the reg, this is not a tune i worked on just changed barrel and probe from .22 and left the HST on min (have a hammer weight) opened up the valve adjuster to just past 4th line.

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Ended up with 1.55
 
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This is the exact information I’m wanting to know as well. I had my gun sent in for the power plenum kit upgrade and I got it back with reg pressure set at 135bar and shooting .30 cal 44gr JSB’s around 960fps avg. im only getting about 57 shots per fill (250-135) and my groups are nowhere near where I want them to be. I’m shooting with a 700mm barrel Others I have spoken with say the reg pressure should be somewhere between 105-100 bar yielding a optimal velocity somewhere between 870-890 FPS. Curious to see what others will post. 
 
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Excellent info Chuck. Thanks for posting that. It will give me a good starting reference point. I sent my gun in for the PP upgrade and it came back with a reg pressure of 135bar shooting between 960fps- 997fps. ES was 37 with a SD of 7.86!!!! Shots were all over the place. I think it was tuned for power shooting heavier slugs as opposed to what I am looking for which is extreme accuracy with pellets out to 100 yds with a nice increase in shot count. I have recorded the measurements already so I can come back to this tune when I decide to shoot the heavier slugs and see what it does with those but for now I gotta retune this gun for the JSB 44’s. 
 
Upvote 0
Excellent info Chuck. Thanks for posting that. It will give me a good starting reference point. I sent my gun in for the PP upgrade and it came back with a reg pressure of 135bar shooting between 960fps- 997fps. ES was 37 with a SD of 7.86!!!! Shots were all over the place. I think it was tuned for power shooting heavier slugs as opposed to what I am looking for which is extreme accuracy with pellets out to 100 yds with a nice increase in shot count. I have recorded the measurements already so I can come back to this tune when I decide to shoot the heavier slugs and see what it does with those but for now I gotta retune this gun for the JSB 44’s.
Click to expand...


You're welcome. I figured if a few of us shooting .30's posted where we were, and what we were tuning for, it'd get a little easier to find a reasonable starting point with the PP upgrades for .30 cal. It definitely sounds like yours came back tuned for slugs. That, to me, anyway, is way past sweet-spot speeds for JSB 44's. You're after the same thing I'm after, and I would definitely tune that rifle down. It would be interesting to hear back from you how close our results were if you set your rifle to the settings I used. If you do that to get in the ballpark, record and post what you get at my settings before you start tuning adjustments. We all know every gun is different, but it would be interesting to see just HOW different like guns with like settings can actually be. Just a curiosity thing.

Good luck, and let us know how it goes tuning it in.
 
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