Fx Impact Fix & Mods for more FPS / FPE

I may end up reaching out to someone to custom build one for me so it will have a thicker side wall to accommodate a gauge.

Do you look at your reg gauge that often?

Me...no! 


the impact is the only one of my guns that does have a reg fitted to the low pressure side, I can’t say that I miss that on my other guns.

the plus side is that it’s easy to check if there is a reg problem but let’s face it, there shouldn’t be. If you are someone who constantly fiddled with reg setting then it is really handy. if you shoot different calibres and at different speeds then it’s very handy. The down side is you feel obliged to fiddle with regged pressure when there is no need The gauges aren’t that accurate so bit of a guess as to the exact pressure. but most annoyingly for me, I can hear the gauge go “ping” every time I pull the trigger. Once I get my impact shooting like I want it to shoot, I am seriously thinking about removing the gauge and fitting a blanking plug instead. I use a digital pressure gauge to set the regs on my other guns so it wouldn’t bother me to screw a gauge into to impact when needed, plus it would save about 1/2ozs in weight, ....at my age, every little helps.





Bb, 










Bb
 
I just want to say thank you to everyone on this thread. My 2017 smooth twist 30cal with a 700mm barrel at 150b was maxed out at 865 fps shooting the 50 grain pellets. After all the mods I am now getting 940 fps at 147b. One thing I did that I don't recall reading about was to drill the rear block out with a 19/64 drill bit. The set screw still tightened up on the valve housing. I was going to get the bigger plenum but now I don't think I need it. Thanks again Brian.
 
I just want to say thank you to everyone on this thread. My 2017 smooth twist 30cal with a 700mm barrel at 150b was maxed out at 865 fps shooting the 50 grain pellets. After all the mods I am now getting 940 fps at 147b. One thing I did that I don't recall reading about was to drill the rear block out with a 19/64 drill bit. The set screw still tightened up on the valve housing. I was going to get the bigger plenum but now I don't think I need it. Thanks again Brian.

Modifying the block's port is hidden a ways back in one of my responses. I used a Dremel tool with a 1/4" mill bit working through that threaded hole to open up and port match the block's port to the valve housing's hole, and to the brass transfer port. I didn't get the latest Plenum, nor did I add the additional plenum either. My shot count is really low and reg fairly high at 160+, but it shoots well and can push 50 grainers well over 1000 fps if I wanted to. 
 
Has anyone modified the valve block in such a way they moved the gauge to be on the side facing out instead of on the bottom or on the bottom of an additional plenum?

The time that it is important to see it is when you adjust your reg pressure. The easiest way to do that is turn the gun upside down. Then you can see your gauge while adjusting the pressure. 
 
Has anyone modified the valve block in such a way they moved the gauge to be on the side facing out instead of on the bottom or on the bottom of an additional plenum?

The time that it is important to see it is when you adjust your reg pressure. The easiest way to do that is turn the gun upside down. Then you can see your gauge while adjusting the pressure.

It's easy to say turn it upside down but what do you do when you have an added plenum and a bag rider.

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Not my gun but you get the point.

This is what I want to do with my Impact when it comes in.
 
Intend to install power plenum...but i can't open this with 11 mm spaner...any comments? Now the shape become round circle

I highly recommend the Knipex - Pliers Wrench for applications like this where you need a secure non marking grip. These may look like pliers but it is a wrench that will never slip. You can't understand until you try them.

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I think “ heavy impact “ mentioned many times in previous posts that you are not going to gain anything if you install both plenums together specially in small calibers . I assume that it will give better results in .35 cal maybe in 0.30 as well. With so much air volume in valve area probably you need to add more hammer weight and strongest spring . 
 
I think “ heavy impact “ mentioned many times in previous posts that you are not going to gain anything if you install both plenums together specially in small calibers . I assume that it will give better results in .35 cal maybe in 0.30 as well. With so much air volume in valve area probably you need to add more hammer weight and strongest spring .

Yeah would probably need a larger valve and seat also to be able to flow the extra air.


 
Glem Chally

yes I forgot to mention it. It supposed that all the rest well known modifications have been done.In my 30 call impact ( with plenum from Poland ) I was thinking to add an external plenum in order to achieve respectable speed for heavy slugs with lower regulator settings . I didn’t have the time to try it yet. The gun is already a beast and accurate for my needs ( with a 71 mm unchocked barrel). I am thinking to leave it as it is for the moment because I am happy with this modes . But this is the point with the impact madness . All time new thoughts and new experiments. We are lucky lately that Edosan took a brake from his daily surgical operations in his gun otherwise we should tinkering our gun every 2-3 days . 😂😂😂.


 
I think “ heavy impact “ mentioned many times in previous posts that you are not going to gain anything if you install both plenums together specially in small calibers . I assume that it will give better results in .35 cal maybe in 0.30 as well. With so much air volume in valve area probably you need to add more hammer weight and strongest spring .

The large volume of air is mostly going to help with big calibers, the diameter of the barrels with the small calibers is too small to feed all the air into there. To maximize flow with the donkey's d*ck style plenum (in the pressure gauge hole) you'll need to make the hole as big as possible, the standard 1/8 BSP gives you a restriction which won't optimize it's function.

The volume of air is not te problem with opening the valve ;) The two things that matter for the valve are it's area which seals the high pressure side from the low pressure side and the regulated pressure. These two combined will give you the force that acts on the valve
 

He is changing out that 3mm set screw to the larger 4mm for safety reasons. There is a lot of pressure on the pellet probe and that 3mm set screw, and there has been at least one reported failure of the 3mm screw, where the probe shot backwards causing damage.
 
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I was organizing some spare parts and I notice a different size probe that I bought without realize the difference.Three of them are for 30 cal . The first and the second I used them already and fit to my gun( impact x 3 generation). The third on the right side is bigger in the length seems stronger and the bottom ( neck ) is different . With a first look seems that is not matching to my probe holder . Even if it can fit will change the the pellet/slug position In the barrel because of its length.
I knew that fx Improved the problem with m3 screw and they change it to m4 but I didn’t knew that they change and the pellet probe size.. So I opened the last fx diagram and I found that they changed as well and the probe holder . There are 2 types of probe holder . Obviously this probe I bought by mistake it fits only in the new improved probe holder. 
They mention in the diagram that there are 2 revisions probe holders according the serial number of the gun but they have the same code 19614 and the retailer is confused and he doesn’t even know about this difference. Is a little bit confusing . I think it could be more clear if fx could change the code and add something like “19614-1”or whatever more understandable.