Fx Impact Fix & Mods for more FPS / FPE

Forums PCP Airguns Fx Impact Fix & Mods for more FPS / FPE

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    mtnGhost
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    heavy-impact

    I don't think there will be any gain going above bore size on the port.

    I think the gain is also from the pellet or slug not dropping off nose first into the port.  So with the center supporting the projectile you can get an even bigger port area on either side of that, essentially making the ports the perfect size for the air volume needed and  also contour shaping the port's exit into the barrel for optimal flow.  

    I agree. I have held back and been far more conservative with port enlargement due to jamming / loading issues (especially 30 cal). I also like this design better for deflecting the brunt of shot pressure on my hand made pellet (slug) pins. I'm also being conservative with the pin diameters, I'm just not sure how much pressure they can take (I'm sure there's math to ballpark that, but meh).

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    heavy-impact
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    I think the gain is also from the pellet or slug not dropping off nose first into the port.  So with the center supporting the projectile you can get an even bigger port area on either side of that, essentially making the ports the perfect size for the air volume needed and  also contour shaping the port's exit into the barrel for optimal flow.  

    I explained in another thread but it's impossible for a projectile to tip into the port if the job was done correctly. FX made the port as wide as it can be reliable so it should never be made wider. You only need to flare the entry, lengthen slightly to match barrel area, radius the short turn and finish by blending all the cuts together for smooth airflow.

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    edosan
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    Another good thing is if you made a mistake, no sweat, you can make another tp in the opposite side, and you do not need another brass piece (on whatever shape you choose). 💡

    So if you slug or pellet get stuck from a shape error, no sweat, you can make another!

    • This reply was modified 5 months ago by edosan.
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    mtnGhost
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    heavy-impact

    Airgun-hobbyist

     

    I think the gain is also from the pellet or slug not dropping off nose first into the port.  So with the center supporting the projectile you can get an even bigger port area on either side of that, essentially making the ports the perfect size for the air volume needed and  also contour shaping the port's exit into the barrel for optimal flow.  

    I explained in another thread but it's impossible for a projectile to tip into the port if the job was done correctly. FX made the port as wide as it can be reliable so it should never be made wider. You only need to flare the entry, lengthen slightly to match barrel area, radius the short turn and finish by blending all the cuts together for smooth airflow.

    In a perfect world, maybe. There's been two inlets on different barrel kits that I bought that had undersized TPs drilled in them. Most recent was the 30 cal kit that had bought from UA, the inlet had to have been meant for a 17 cal. It was under 5mm and looked obscenely small.

    An observation that I made – in terms of velocity, I never saw a performance hit by inadvertently going a little wider than the block's port. I'm also fairly certain that I have widened every inlet that I have modified unintentionally lol

    @edosan – yep! That takes some stress off of modifying them 😂 

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    Vadimas
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    • This reply was modified 4 months ago by Vadimas.
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    T3PRanch
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    Since the post above was emptied of content this one was also since it relied on the post above it for meaning! :P

    • This reply was modified 4 months ago by T3PRanch.
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    srtmat
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    I’ve been following this thread for a while and I thought I would add my results from my Crown Continuum.

    I ported both 380mm and 700mm barrels as well as the probe.

    STOCK GUN FACTORY SET AT 150 bar. 

    •380mm PW-Max 850-855 with 25.4gr

    •700mm PW-Max 995 with 25.4gr

    •700mm PW-Max 900-905 with 34gr

    I just finished porting both barrels and the probe this afternoon and re-power tuned with the 700mm slug barrel and the 34gr.  Reg pressure set to 155 bar. I didn’t mess around much above 155 seemed like it was about tapped out with stock internals.

    •Ported 380mm PW-Max 875 with 25.4gr.

    •Ported 700mm PW-Max 1040 with 25.4gr.

    •Ported 700mm PW-Max 935-940 with 34gr.

    I actually had the 380 barrel ported prior to this power tune and I was able to get the 25.4gr going 875. I’m sure it will go up a little bit with the current tune but I really don’t think it pays to port the 380 mm barrel. 

    I want to shoot slugs at some point and was looking for a little bit of headroom.  With limited time I did shoot a few groups 700mm 34gr and found that the gun was actually shooting best backed down to PW4 at 908. I didn’t try slower but I would imagine PW3 would also be great as it shot them great at 875 prior to the tune.

    Definitely picked up some good FPS and a pretty easy mod to do. No problems with loading pellets.

     

    12/15/19 Update.

    I put the 380mm barrel on and ran it over the Crony.

    25.4gr JSB’s           34gr          28.25 H&N

    Max 890                 795               850

    PW5 883

    PW4 880

    PWC 867

    PW3 855

    PWD 825

    PW2 808

    Makes me wonder if I can shoot FX Hybrid slugs from the 380mm.

    • This reply was modified 3 months ago by srtmat.
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    srtmat
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    A few pics of the work.  I removed a bit of material from the inside of the probe to thin and “knife edge” it.  Used the blue Dremel chainsaw sharpener then polished with some fine grit rubbery type of bits I had from who knows where.

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    ogodaw
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    Test plenum from Poland 

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    edosan
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    srtmat

    A few pics of the work.  I removed a bit of material from the inside of the probe to thin and “knife edge” it.  Used the blue Dremel chainsaw sharpener then polished with some fine grit rubbery type of bits I had from who knows where.

    Good job and great results! 

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    edosan
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    Regulator creep or leak?, no sweat, check this great video from Newman Buck (FX USA)

     

     

     

    • This reply was modified 3 months ago by edosan.
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    tomhu0918
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    Hello Guys,

     

     I added the plenum and modified valve housing & VS and TP and hammer weight.

    My target is speed is 930fps. NSA .22 slug 27gr.

    Right now I can get 960fps easily just only use 130bar.  I was wondering what is the best way to tune the gun.

    Should I increase the reg pressure to 150bar and use valve knob to reduce the velocity to 930fps?

    Which way is the best for saving the air consuming and make the impact quieter?

    High or low reg pressure?

    • This reply was modified 3 months ago by tomhu0918.
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    edosan
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    tomhu0918

    Hello Guys,

     

     I added the plenum and modified valve housing & VS and TP and hammer weight.

    My target is speed is 930fps. NSA .22 slug 27gr.

    Right now I can get 960fps easily just only use 130bar.  I was wondering what is the best way to tune the gun.

    Should I increase the reg pressure to 150bar and use valve knob to reduce the velocity to 930fps?

    Which way is the best for saving the air consuming and make the impact quieter?

    High or low reg pressure?

    There are several videos on tuning (including FX videos), the higher the reg pressure more air you will use. Also the higher the reg pressure, louder your impact will be, that is why tuning is the balance between reg pressure, hst and valve opening. 

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    tomhu0918
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    I forgot which video said the lower reg pressure need more air to push the projectile.

    Which it need more air and louder. But I am not sure it is correct or not.

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    srtmat
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    Fantastic AMP reg video!

    Thanks for sharing edosan.

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    Vadimas
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    ogodaw

    Test plenum from Poland 

     

     

    The tests shall be carried out with oil or water hydraulically. Only a person with little mind can conduct air tests!

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    mtnGhost
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    Vadimas

    ogodaw

    Test plenum from Poland 

     

     

     

     

    The tests shall be carried out with oil or water hydraulically. Only a person with little mind can conduct air tests!

    Would have been cool to have seen him strike the valve with a large 🔨 😂

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    Sjoerd
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    Hello guys,

    Next week i will receive my impact mk2 with 700mm .25 barrel with slug liner.

    I want to shoot the 38,5gr NSA slugs, the heaviest i can get around here. I did order an power upgrade kit with enlonged tp, modified pellet probe, 7gram hammer weight, modified valvehousing and plenum.

    But if i dont need to, i dont want to take the gun completely appart when i get it. 

    Will i get enough speed (around 960fps) when i only replace the tp and pellet probe ? Or should i build in the complete power upgrade ?

     

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    heavy-impact
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    Sjoerd

    Hello guys,Next week i will receive my impact mk2 with 700mm .25 barrel with slug liner.I want to shoot the 38,5gr NSA slugs, the heaviest i can get around here. I did order an power upgrade kit with enlonged tp, modified pellet probe, 7gram hammer weight, modified valvehousing and plenum.But if i dont need to, i dont want to take the gun completely appart when i get it. Will i get enough speed (around 960fps) when i only replace the tp and pellet probe ? Or should i build in the complete power upgrade ?

    You will need it all.

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    ahmed
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    The very best that I could do without hammer weight and plenum is 945fps and that is on (.25 – 700mm Slug liner Barrel – 34gr JSBs) Modified valve housing, ported TP and probe, Delrin C3 bumper. Hammer spring maxed out and regulator maxed till it dropped then backed up a bit.

    Like heavy said, you will need it all for sure to spit them 38.5gr out at the speeds your looking for.

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