Fx transfer port and prope mod.

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I have been tuning with the new PP arrangement this morning in my FX Impact MKII.

The setup now is:

  • New PP plenum tube
  • New valve rod and housing
  • Original valve spring (Inside the new plenum)
  • Original hammer spring
  • Original rubber ball valve cap
  • New hammer (w/built-in C3)
  • No added hammer weight
  • Modified Huma dual port roughly 6mm x 6mm
  • Modified probe to match dual TP
  • Shooting JSB MKIIs w/sorted weight to 34.12gr to 34.42gr (Average weight 34.27gr).
  • JSBs sized to .251"
  • Regulator set at 135 psi.

With PW set to Max I'm getting 942 fps

With PW set to 5 I'm getting 929 fps

With PW set to 4 I'm getting 899 fps

With PW set to 3 I'm getting 846 fps

The ES for all of these settings is coming in at 1 to 3 fps on these short test runs. It may spread a bit more on longer runs, but still very tight and good enough for my ranges that are typically within 100 yards.

The accuracy has improved even more now that I have a better balanced tune dialed in. I can hear the difference as well. With the PW set on 4 or 5, It looks to be near drilling holes at 52 yards depending my shooting abilities off of a wobbly plastic table and bag setup. I'll have to do more test to see for sure.

This tune should work great for the MKIIs and the Kings. I'll probably need to adjust the reg for the .30 caliber, which is next to get sorted out. I want the .30's shooting at least 100 FPE. This was the reason for getting the Impact to begin with, so I could match my brother's .22 rimfire power while shooting together. I think I'll finally get there with an Impact.

I consider my .357 Slayer to be in a class by itself at 280 to 300 FPE. That gun is simply amazing. I don't think you'll find a better built gun than a Slayer, but the Impact sure is close in build quality on many fronts. I just love how well the FX Impact performs. Man, this is a gun for me, for sure.


 
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What is a transfer port hole size in the FX Impact rear block? Is that hole OD differing between calibers or the block is a common part # between calibers?

(I would assume maybe the .30 but definitely the .35 shall have a bigger hole ((area)) for a bigger air volume passing through).

In need for speed, the last limiting factor is the "area of a hole" in a liner ID, only way to help is to increase the molecular density....go and shoot in -20C and below ;)

Edit:

Not sure what would be a speed difference @ between -20C and/or -40C, for that to test I would need to wait a next 5-6 months


 
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The Valve Housing transfer hole size is less then 6.5 mm ID (I only have this closest drill size and the shank doesn't go in).

The black delrin seal head is 7.5 mm OD.

Waiting for my order of new/spare PP Valve Housing and Valve Pin (complete kit as how they selling only) also if I can reach to a Rear Block as well.

I would try to replace the black delrin seal with a bigger OD in order to be able to re-drill the transfer hole for next size up (let say 7.1 mm ID).

Right now there is a max air-room of 1.5 mm per side on circumference (valve housing hole is 10.63 mm ID) to play with dimensions, not crashing into outer oring.

What glue/epoxy you would recommend, I understand the dimension shall be press fit on rod as well.



1597597265_1238401385f3966518659c8.72851687.jpg


1597597682_15275183475f3967f2532091.81181646.jpg



 
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I have been tuning with the new PP arrangement this morning in my FX Impact MKII.

The setup now is:

  • New PP plenum tube
  • New valve rod and housing
  • Original valve spring (Inside the new plenum)
  • Original hammer spring
  • Original rubber ball valve cap
  • New hammer (w/built-in C3)
  • No added hammer weight
  • Modified Huma dual port roughly 6mm x 6mm
  • Modified probe to match dual TP
  • Shooting JSB MKIIs w/sorted weight to 34.12gr to 34.42gr (Average weight 34.27gr).
  • JSBs sized to .251"
  • Regulator set at 135 psi.

With PW set to Max I'm getting 942 fps

With PW set to 5 I'm getting 929 fps

With PW set to 4 I'm getting 899 fps

With PW set to 3 I'm getting 846 fps

The ES for all of these settings is coming in at 1 to 3 fps on these short test runs. It may spread a bit more on longer runs, but still very tight and good enough for my ranges that are typically within 100 yards.

The accuracy has improved even more now that I have a better balanced tune dialed in. I can hear the difference as well. With the PW set on 4 or 5, It looks to be near drilling holes at 52 yards depending my shooting abilities off of a wobbly plastic table and bag setup. I'll have to do more test to see for sure.

This tune should work great for the MKIIs and the Kings. I'll probably need to adjust the reg for the .30 caliber, which is next to get sorted out. I want the .30's shooting at least 100 FPE. This was the reason for getting the Impact to begin with, so I could match my brother's .22 rimfire power while shooting together. I think I'll finally get there with an Impact.

I consider my .357 Slayer to be in a class by itself at 280 to 300 FPE. That gun is simply amazing. I don't think you'll find a better built gun than a Slayer, but the Impact sure is close in build quality on many fronts. I just love how well the FX Impact performs. Man, this is a gun for me, for sure.

The original valve Spring inside the PP ? it will squeeze the white oring in PP tube ? 
right ?
Click to expand...


 
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Souhaib,

I used the original black plastic spring guide from the hammer spring. It fits perfectly inside the plenum tube arm to support the old valve spring inside the new power plenum tube. I no longer use this arrangement. I went full power plenum kit, and have a slug kit on the way. The hybrid method will keep your cocking effort to a minimum if not wanting more power than this hybrid setup will give you.
 
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