External Plenum for FX Impact 30

Well, except the winner, Justin Welch... No additional plenum. If you are going to shoot .30 at optimum speeds, say 875 to 925 FPS, there is no need to add a plenum or any other power upgrades for that matter. If you are going to shoot heavy slugs at higher speeds, or if you're a science denier, and want to shoot the .30 pellets at over 1000 FPS, that would be the reason to upgrade the power potential... But for accurate best BC speed pellets, no reason.

I think it's more than just adding the external plenum. It wont work that way. The internal needs to be bore out for it to work. It's not plug in play. I know ernest used to do it if you ship your gun to fx. But idk if he still does it now. Wish it was that easy just buy it and put on. 

Is a tricky business to "generalize" (is that word right in english!? jajaj)

It depend on what impact do you have, what speed do you want and what projectile you will shoot ... and finally are we talking on stock impact or modded impact? (will not go on modded impacts). Stock ones:

Impact X, valveseat (VS) 5.5mm, ValveTube (VT aka plenum) 20cc

Mk2 Early Release, VS 5.5mm, VT 25cc

MK2 Latest release, VS 6.35mm, VT25cc

As you can see all this changes affect the speed, precision and harmonics...so and FOR example, to achieve 900fps you will need different configurations for those 3. The plenum might be needed or not, adding an external plenum add more regulated air volume, so in theory even achieving 900fps on the pellet/projectile you choose and without the plenum, the plenum addition will help to lower your regulator pressure, ergo your tension on the spring, ergo the hammer strike (less force to open the valve), that can lead to less vibration and better accuracy ... but like I said in THEORY ... your Impact might achieve the "optimum" without a plenum, and adding one will improve nothing. 

At the end, precision is all that matter is the ultimate goal (at least for me)

BTW: Adding an external plenum is not plug and play, mods need to be made...of course you can add one and do nothing but actually will not help as it supposed to) 

First you get the gun, then you get the speed, and then you got the Accuracy! (scarface mode on!)

You can order an eccentric plenum from Poland which is larger than the external ones and doesn't require any modification to your gun. $140 shipped [email protected]

You'll get higher velocity at a lower reg pressure and if you want more power just elongate the brass transfer port/pellet probe and add a larger valve seat to reach 110 to 130 fpe.

https://youtu.be/JdoTMsyuVQY

Is a tricky business to "generalize" (is that word right in english!? jajaj)

It depend on what impact do you have, what speed do you want and what projectile you will shoot ... and finally are we talking on stock impact or modded impact? (will not go on modded impacts). Stock ones:

Impact X, valveseat (VS) 5.5mm, ValveTube (VT aka plenum) 20cc

Mk2 Early Release, VS 5.5mm, VT 25cc

MK2 Latest release, VS 6.35mm, VT25cc

As you can see all this changes affect the speed, precision and harmonics...so and FOR example, to achieve 900fps you will need different configurations for those 3. The plenum might be needed or not, adding an external plenum add more regulated air volume, so in theory even achieving 900fps on the pellet/projectile you choose and without the plenum, the plenum addition will help to lower your regulator pressure, ergo your tension on the spring, ergo the hammer strike (less force to open the valve), that can lead to less vibration and better accuracy ... but like I said in THEORY ... your Impact might achieve the "optimum" without a plenum, and adding one will improve nothing. 

At the end, precision is all that matter is the ultimate goal (at least for me)

BTW: Adding an external plenum is not plug and play, mods need to be made...of course you can add one and do nothing but actually will not help as it supposed to) 

First you get the gun, then you get the speed, and then you got the Accuracy! (scarface mode on!)

Click to expand...

I have an mk2 but How do i know 

if my VS is 5.5 or 6.35 ? For serial number ?

If you were travelling around shooting in the bigger competitions, wouldn't you want all the upgrades on your rifles?. Just for the intimidation factor alone! 

FX sells the 30 Impacts to perform as advertised, which is shooting the 44.75 grain JSBs around 865 fps. From the few examples I've seen, you will get a max of around 880-890 fps with a 600 mm barrel, and around 915 fps with the 700 mm. This is with an out of the box Mk II, with the hammer spring and regulator pressure adjustments close to max.

As mentioned, shooting slugs drives the "need" for speed to higher levels, and that's one driving force to mod these guns. That said, the nice feature of adding plenum volume is it allows velocity improvements at lower reg pressures, with guys posting nice results at 140 bar or lower.

@Souhaib as far as I know, only checking the ValveHousing 

FX quit selling power parts because of liability issues. My fear is that some noob is going to attach a Yong Heng fitting or other crappy part to their gun to use as a plenum, like some are already doing and they’re going to get severely injured or killed when 2600psi strips poorly made threads and sends that thing into their head or jugular which is only about 3” away. 

A well made part by Ernest or Edosan is a different story but I’m afraid FX could see the writing on the wall and got out before a catastrophic injury resulted from non-FX parts being sold by FX. Other than Edosan or Ernest, whom I trust to have thoroughly tested these parts, it can be a huge risk. Something bad will happen sooner or later when inexperienced air gunners push the limits. I don’t usually worry about things like this much, but it’s something to think about. 

Stoti

FX quit selling power parts because of liability issues. My fear is that some noob is going to attach a Yong Heng fitting to their gun to use as a plenum, like some are already doing and they’re going to get severely injured or killed. A well made part by Ernest or Edosan is a different story but I’m afraid FX could see the writing on the wall and got out before a catastrophic injury resulted from non-FX parts being sold by FX. The power is great but other than Edosan or Ernest, whom I trust to have thoroughly tested these parts, you’re taking a huge risk. It will happen sooner or later! 

Stoti

Click to expand...

Of all the external plenums I've seen the yong heng is by far the strongest... like 3 X stronger than the ones with larger diameter, thinner walls and no radiused ends.

I would bet the farm on the yong heng if someone is willing to test them to destruction.

@stoti and is the reason why I am reluctant to sell plenums , I have said it before, but an external plenum not tested fully or wrong machined, can be the most dangerous part on the Impact. 

FX quit selling power parts because of liability issues. My fear is that some noob is going to attach a Yong Heng fitting or other crappy part to their gun to use as a plenum, like some are already doing and they’re going to get severely injured or killed when 2600psi strips poorly made threads and sends that thing into their head or jugular which is only about 3” away. 

A well made part by Ernest or Edosan is a different story but I’m afraid FX could see the writing on the wall and got out before a catastrophic injury resulted from non-FX parts being sold by FX. Other than Edosan or Ernest, whom I trust to have thoroughly tested these parts, it can be a huge risk. Something bad will happen sooner or later when inexperienced air gunners push the limits. I don’t usually worry about things like this much, but it’s something to think about. 

Stoti

Click to expand...

Everyone have to diss on the china man made product. Smh. Those cheap crappy filter you take about. They are rated for 4500 psi. The 2600 psi you claim have nothing on it. Plus most people set their reg pressure to 1500 psi to 2000 psi. I've been using these you called cheap crappy poorly made filters on the yong heng to fill my tanks to 4500 psi for 2 years with no problems. Trust me. Its gonna take more than 2600 you claimed to break its threads or walls. With thousands of these cheap yong heng filters being sold and use..please link me to one where it blew up and killed someone.

Heavy, just using the Yong Heng as an example because I knew it by name. Those are the ones I see being used a lot because they “fit”. I’m not trying to point the finger at any particular brand, just make people aware that if not tested properly, installed properly, used properly, there can be a problem. Especially when the parts are repurposed or not intended to be used as a plenum. 

Dan, for normal use, you’re absolutely fine.

Stoti

2fast—— I said Yong Heng or other crappy part. I never said anything derogatory about the “China man” or filter or called the Yong Heng cheap or crappy product. Don’t put words in my mouth. I said Yong Heng or “a” crappy part. I was simply using the Yong Heng as an example because it is a part people are using often. The point is not who makes these parts, it’s that inexperienced people are attaching parts places they were not designed to be. And, many of these people don’t know what they’re doing. Sooner or later something bad is liable to happen. Just because you are capable and feel that it’s okay doesn’t make it safe for everyone.

I also never said the part blew up and killed someone when being used as it’s intended to be, on a compressor. I said it’s liable to happen if someone who doesn’t know what they’re doing uses parts purposed for other things.

And, most people I know don’t usually run their Impacts at 103-130bar like you said, although debatable.

Stoti

The YH filter is an engineered pressure vessel that is at least 3 times stronger than any of the tubing made external plenums that we've seen because of it's smaller diameter thicker walls, radiused end, very thick cap and heavy threads. I have no doubt that it would be the last thing to fail in the chain of parts. It's over engineered for 4500 psi so the pressure it sees as a plenum is nothing. If someone wants to make an external plenum, the yong heng inline filter housing itself would be the safest part on the gun.

The adapter would be the weakest point if you left it 1/8"/M10 but even if it failed the small area of pressure wouldn't propel it fast of far with the sheer angle and weight of the part.

I machined my rear block and YH housing to M16 since I want max power for .30 slugs when the liners hit the market.

2fast—— I said Yong Heng or other crappy part. I never said anything derogatory about the “China man” or filter or called the Yong Heng cheap or crappy product. Don’t put words in my mouth. I said Yong Heng or “a” crappy part. I was simply using the Yong Heng as an example because it is a part people are using often. The point is not who makes these parts, it’s that inexperienced people are attaching parts places they were not designed to be. And, many of these people don’t know what they’re doing. Sooner or later something bad is liable to happen. Just because you are capable and feel that it’s okay doesn’t make it safe for everyone.

I also never said the part blew up and killed someone when being used as it’s intended to be, on a compressor. I said it’s liable to happen if someone who doesn’t know what they’re doing uses parts purposed for other things.

And, most people I know don’t usually run their Impacts at 103-130bar like you said, although debatable.

Stoti

Click to expand...

Trust me I know what you were referring to when you say noobs are attaching yong heng fittings to their impacts and I'm not putting words into your mouth. Heavy impact also know what you were referring to that's why he is telling you, it is not as weak and poorly made as you claimed. You were talking about this yong heng filter. Made cheaply and poorly by the chinese. Yet it can handle 4500 psi easily.

Again, not about the Yong Heng and you did absolutely put words in my mouth! It's all in black and white. 

My point is simply to warn new Impact owners, who are after more power or asking about plenums that there can be dangers involved when putting aftermarket parts, not designed by FX, on their rifle without proper knowledge or experience. Sure, many people have the skillset, knowledge and proper parts to do it, however, many do not. Do a search on You Tube or the Facebook groups and look at all of the people making plenums for their Impacts, sooner or later someone will start selling an untested product to make a quick buck, someone will have either made it wrong or installed it wrong and they'll get hurt. 

Stoti

I wouldn't risk my life with Chinesium, but that's just me. To each their own!

Long live youg heng! 



Any certified (important) hpa filter for 300bar + will take the regulator pressure ... too small imo tho. But without modding the vh and drilling the block, is just "Simon says" I have seen it to the level that people says that adding a plenum will not help at all.

Actual mk2 (latest) with a bigger bore vs has enough power for most shooters, and the new 0.35 ... Man I heard some rumors ... It might even be close (but not that close jajaj) to Silver Surfer