• The AGN App is ready! Search "Airgun Nation" in your App store. To compliment this new tech we've assigned the "Threads" Feed & "Dark" Mode. To revert back click HERE.

Tuning FX Impact M3 valve & seat upgrade

Jump to latest Follow Reply
mubhaur

mubhaur

Member
Nov 8, 2015
2,235
970
52
Karachi, Pakistan
20220618_201327.jpg
20220618_201305.jpg


Used old style valve housing that used to use removable valve seat. Made a new seat of bigger size. Machined the valve housing to fit in M3 72cc plenum. Made a new valve out of peek and with a bit bigger outer dia.

All other settings remaining identical.

On same settings the gun which was previously giving 925fps with 25 grain .25 pellets, now gives 970fps.

To come back to previous desired fps, reduced the power wheel from 8 to 4.

I think its another way to skin a cat. A substitute of power block.

Umair Bhaur
 
Do you have any pictures of the fitment of the new valve seat against the valve? I'm wondering if theres much better airflow to be had if we decrease the diameter of the steel cone section.

Also- It looks like you machined back the Peek quite a bit- I'm curious how much that reduces what you can "open" the valve to now?

Nice work!
 
Last edited:
Upvote 0
Seeker said:
Power block should give you more because it has a bigger channel plus the flow is slightly optimized. You could gain another 20fps maybe.
Click to expand...
Screenshot_20220826-181742_Gallery.jpg


I understand that if I just use a bigger grub screw to hold the valve housing in the block just like power block system uses it will allow for making accordingly bigger hole in the block just as is in power block system (as I understand), I can squeeze more fps without changing the settings.

This is just experiments as power block is needed for slugs and I only use pellets.

But I understand that through this mod I can achieve the same level of power as power block produces. Who knows a bit more !
 
Upvote 0
mubhaur said:
I understand that if I just use a bigger grub screw to hold the valve housing in the block just like power block system uses it will allow for making accordingly bigger hole in the block just as is in power block system (as I understand), I can squeeze more fps without changing the settings.
Click to expand...
True, but you haven't done it yet so there may be some additional gains.

mubhaur said:
But I understand that through this mod I can achieve the same level of power as power block produces.
Click to expand...
Not exactly because the valve housing in the Power Block is slightly optimized flow wise. Apart from that orings sealing the barrel are slightly better placed resulting in less wasted volume. These changes might give additional 5-10FPS. But more or less you are able to achieve Power Block power levels without the original Power Block.
 
  • Like
Reactions: mubhaur
Upvote 0
Seeker said:
Not exactly because the valve housing in the Power Block is slightly optimized flow wise. Apart from that orings sealing the barrel are slightly better placed resulting in less wasted volume. These changes might give additional 5-10FPS. But more or less you are able to achieve Power Block power levels without the original Power Block.
Click to expand...


Not trying to pick on you here- but has anyone actually measured and reported the differences? If not, we should really try to do that collectively. People quote the advertising all the time without pointing out what exactly is different. I can see the valve seats are slightly different (I haven't tried to measure it yet) and the powerblock trasnfer port is SLIGHTLY larger. but overall the biggest differences i see are the o-rings being embedded in the block vs valve housing itself. I'm genuinely curious how much of a difference there really is. My powerblock transfer port is drilled out, but if somoene had the ability to measure how it comes from FX, that would help put these differences down in numbers. I have some equipment that i could mesaure the valve itself and get some solid info.. Just a thought
 
Last edited:
  • Like
Reactions: mubhaur
Upvote 0
LSRHokie said:
Not trying to pick on you here- but has anyone actually measured and reported the differences? If not, we should really try to do that collectively. People quote the advertising all the time without pointing out what exactly is different. I can see the valve seats are slightly different (I haven't tried to measure it yet) and the powerblock trasnfer port is SLIGHTLY larger. but overall the biggest differences i see are the o-rings being embedded in the block vs valve housing itself. I'm genuinely curious how much of a difference there really is. My powerblock transfer port is drilled out, but if somoene had the ability to measure how it comes from FX, that would help put these differences down in numbers. I have some equipment that i could mesaure the valve itself and get some solid info.. Just a thought
Click to expand...
I saw about 25-30FPS from drilling out the port and switching to an E.R. DTP. Currently shooting 62-grain varmint knockers 1110FPS for 170FPE.. but I also have other modifications.
 
Upvote 0
TwoLoe88 said:
I also learned the hard way that if you drill the valve house out to 8.5, you'll drill out the sealing surface of the valve pin.
Click to expand...
I'm mainly curious if/ how much bigger the valve seat/ opening is, which is why this post interested me. With my .357, I can open up the rest of the passages, but i've been wondering if that is really the restriction for big bore. I will say the Huma .357 TP is massive and no longer is the restriction with my drilled TP in the powerblock. Next on my list of to-dos is measure all the spring rates to see what the differences actually is between "regular" valve springs and "slug kit" springs are, and if the .357 springs are any different. I have an old Chatillion spring rate gauge here that i used to pretty well tune my benjamin marauder. Im just sad to see theres no where as much info on these FX rifles
 
Upvote 0
LSRHokie said:
I'm mainly curious if/ how much bigger the valve seat/ opening is, which is why this post interested me. With my .357, I can open up the rest of the passages, but i've been wondering if that is really the restriction for big bore. I will say the Huma .357 TP is massive and no longer is the restriction with my drilled TP in the powerblock. Next on my list of to-dos is measure all the spring rates to see what the differences actually is between "regular" valve springs and "slug kit" springs are, and if the .357 springs are any different. I have an old Chatillion spring rate gauge here that i used to pretty well tune my benjamin marauder. Im just sad to see theres no where as much info on these FX rifles
Click to expand...
I have found out that just turning up the reg makes a big difference, I was able to get to 210 bar on the reg before my stock valve pin is maxed out, I also have a custom tungsten weight to keep it open as long as possible.
 
Upvote 0
TwoLoe88 said:
I have found out that just turning up the reg makes a big difference, I was able to get to 210 bar on the reg before my stock valve pin is maxed out, I also have a custom tungsten weight to keep it open as long as possible.
Click to expand...
Oh wow. I got up to 180 before I blew the o-ring on the back of the valve rod. Hopefully that was just a fluke, as turning up the pressure would certainly be nice. I assumed it was just too much for the o-rings in general
 
Upvote 0
mubhaur said:
View attachment 285424View attachment 285425

Used old style valve housing that used to use removable valve seat. Made a new seat of bigger size. Machined the valve housing to fit in M3 72cc plenum. Made a new valve out of peek and with a bit bigger outer dia.

All other settings remaining identical.

On same settings the gun which was previously giving 925fps with 25 grain .25 pellets, now gives 970fps.

To come back to previous desired fps, reduced the power wheel from 8 to 4.

I think its another way to skin a cat. A substitute of power block.

Umair Bhaur
Click to expand...
please can u tell me the OD dia of both the peek poppet you made ??
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu