Increasing regulator pressure does not gain velocity - FX IMPACT X

[SW]

Hello all,

I recently upgrade my FX IMPACT X with power plenum kit and with 700mm .30 barrel. I find out when I increase reg pressure from 125 bar to 135 bar, I actually loose velocity from 933 fps to around 920. I am shooting 44.75 grain jsb exact pellet. I have maxed out tension spring. further increase reg pressure seems does not help. what is it going on here?

any help is highly appreciated! Thank you.

Regards,

S.W.

 

[grrbrrr]

You need to turn up the hammer spring. The pressure increase has increased the force needed for the hammer spring to open the valve. Some people put weighted spacers/washers where the hammer spring is so that it has more spring compression and force to open the valve. The new Fx impact slug probe kit has those parts in it. Ernest row talks about this a little bit in his video on how to install the slug power kit. I would first try to increase the hammer spring tension.


hope this helps,

grant 

 

[SW]

Thanks Grant! I suspect the valve was not opening big enough, with higher pressure, making it even more difficult. so indeed higher tension on hammer spring or hammer weight.. on that direction...I just hoped it could work when installed... apparently not..

 

[Leon83]

Increase the tension on hammer spring until you reach highest velocity then decrease hammer spring tension so the velocity drops by 3-5%. Such setting will be the most efficient in terms of air consumption. This would be the highest velocity for the pressure set on reg. 

 

[SW]

@Leon83 I understand.. but my issue is: increasing reg pressure does not increase velocity. I first want to reach my desired fps range for my slug hopefully, then I can fine tuned it to make it more efficiently.. currently I simply cannot reach to the 960 fps range with my desired slug e.g. 61 grain nielsen.

 

[Butch]

If you used the the spring that came with the kit it is 52mm and not enough spring to open the valve above that pressure. Us your old spring (57mm) instead and you will get all the FPS you will want. 
Butch

 

[Glem.Chally]

@Leon83 I understand.. but my issue is: increasing reg pressure does not increase velocity. I first want to reach my desired fps range for my slug hopefully, then I can fine tuned it to make it more efficiently.. currently I simply cannot reach to the 960 fps range with my desired slug e.g. 61 grain nielsen.

Thats 125fpe, you might be at the limit there with that valve adjuster spring.

 

[Butch]

I missed that part with the 61 grain slugs Glem. Lol. I was thinking the 44s. Might be asking a little to much for the 61s. Good catch Glem. 
Butch

 

[Glem.Chally]

 Not impossible though, with a softer (lighter) return spring you might get there.

But it wont be efficient at that power level, maybe 30-40 shots.

 

[SW]

@Butch thanks! that seems to be a common advice to use the old hammer spring 57mm..

 

[SW]

@Glem.Chally I probably ask too much, might be over the limit of what impact can do.... I might end up with 47, 49, 51 grains range.. I like the speed.. so i might need to go down with slug weight. I am new to slug, I like the performance of slug with windy condition. pellet seems just cannot do...

 

[Glem.Chally]

@Glem.Chally I probably ask too much, might be over the limit of what impact can do..

.. I might end up with 47, 49, 51 grains range.. I like the speed.. so i might need to go down with slug weight. I am new to slug, I like the performance of slug with windy condition. pellet seems just cannot do...

Not necessarily, but beyond what its doing now you might need a lighter return spring under the valve adjuster. Maybe the 55s would be a great slug to push, they should buck the wind just as well. I shot some .30 slugs this past weekend and even at 830fps they were very accurate.

 

[SW]

thanks all! after changing back to my old 57mm spring. my reg pressure is set at 130 bars, max out tension spring, I am able to push 44.7 grain jsb exact, at 978 fps with 45 fps increase from 52mm spring.. now I am more confident that I am able to push middle weight slug at around 930 - 950 fps range.

 

[bigHUN]

I had the DIY enlarged Huma dual port with enlarged FX pellet probe (in the middle), the speed was maxing at 960 fps with 34 gr MK2's and 119 bar maxed out HS

I just swap to this new Huma dual port (a new kit that comes with the dual port + pellet probe as well) and lost about 30ish fps, I did not enlarged these pocket openings yet. Same reg pressure 119 bar HS maxed out.

Next thing I will try Ernest 45 degree port pocket openings, if any good. I have one spare brass piece still stock.

 

[SW]

I had the DIY enlarged Huma dual port with enlarged FX pellet probe (in the middle), the speed was maxing at 960 fps with 34 gr MK2's and 119 bar maxed out HS

I just swap to this new Huma dual port (a new kit that comes with the dual port + pellet probe as well) and lost about 30ish fps, I did not enlarged these pocket openings yet. Same reg pressure 119 bar HS maxed out.

Next thing I will try Ernest 45 degree port pocket openings, if any good. I have one spare brass piece still stock.

yes.. I also have the huma tp and prob installed on my impact 700mm .30 barrel kit. at 130 bars, it shoot at 978 fps (after replace 52 mm with 57mm spring) with 44.75 grain jsb pellet. it has 95 fpe, 129 joules. it seems powerful enough for me ... at this stage.. I only want to shoot 43 grain slug at around 960 fps.. it would be sufficient at my initial stage..

 

[bigHUN]

.......

yes.. I also have the huma tp and prob installed on my impact 700mm .30 barrel kit. at 130 bars, it shoot at 978 fps (after replace 52 mm with 57mm spring) with 44.75 grain jsb pellet. it has 95 fpe, 129 joules. it seems powerful enough for me ... at this stage.. I only want to shoot 43 grain slug at around 960 fps.. it would be sufficient at my initial stage..

I asked around everywhere and I cannot get that longer 57mm spring to my hands. I would order from McMasterCar but I would need the spring details (OD, wire OD, material, load). The spec is different between the 57mm and 52mm not just the length, not the same stiffness.

 

[Spierings]

You can get more hammer spring tension bij swapping the hammer spring slide bar and spring bucket.



https://youtu.be/rPUxx1Z3AZY

 

[SW]

.......

yes.. I also have the huma tp and prob installed on my impact 700mm .30 barrel kit. at 130 bars, it shoot at 978 fps (after replace 52 mm with 57mm spring) with 44.75 grain jsb pellet. it has 95 fpe, 129 joules. it seems powerful enough for me ... at this stage.. I only want to shoot 43 grain slug at around 960 fps.. it would be sufficient at my initial stage..

I asked around everywhere and I cannot get that longer 57mm spring to my hands. I would order from McMasterCar but I would need the spring details (OD, wire OD, material, load). The spec is different between the 57mm and 52mm not just the length, not the same stiffness.

these sites have them. you probably want to double check if they are 57mm..

https://www.huma-air.com/FX-Impact-Tuning-Hammer-Spring

https://spares.bagnallandkirkwood.co.uk/product/part-c7-fx-impact-hammerspring/

 

[SW]

@Spierings yes, I saw this one before.. that would be the next step if I ever needed more power...

 

[bigHUN]

I asked around everywhere and I cannot get that longer 57mm spring to my hands. I would order from McMasterCar but I would need the spring details (OD, wire OD, material, load). The spec is different between the 57mm and 52mm not just the length, not the same stiffness.

these sites have them. you probably want to double check if they are 57mm..

https://www.huma-air.com/FX-Impact-Tuning-Hammer-Spring

https://spares.bagnallandkirkwood.co.uk/product/part-c7-fx-impact-hammerspring/

Yes I saw these springs but non of them saying what is a length.