Fx Impact Fix & Mods for more FPS / FPE

[Hyperdave]

@heavy-impact

Hey! Nice CAD drawing... Is there an open source for those or have you done your own?

 

[wajie316]

Start at the outside making it 7.4mm then make the elongated portion and then smooth the transition between them.

I do this with a li-ion rotary tool and a carbide burr, second one from the right in pic ⑲.

Polish the area last using a felt tip and red polishing compound.

Use low to medium speed when removing metal for best control. Polish at high speed.

Heavy impact,

So we tried to improvise it and we did get around 15fps gain. Its now shooting around 952-955fps at 150 bars. 

Let me know if we can improve it a bit more since this was the first time that we did something of this sort. Please note that the transfer port was elongated before as well but we tried to replicate your design. 

 

[heavy-impact]

@heavy-impact

Hey! Nice CAD drawing... Is there an open source for those or have you done your own?

I copied them from the forum here in different places. The search function doesn't work well at AGN anymore so here's what I have.

 

[mtnGhost]

Start at the outside making it 7.4mm then make the elongated portion and then smooth the transition between them.

I do this with a li-ion rotary tool and a carbide burr, second one from the right in pic ⑲.

Polish the area last using a felt tip and red polishing compound.

Use low to medium speed when removing metal for best control. Polish at high speed.

Heavy impact,

So we tried to improvise it and we did get around 15fps gain. Its now shooting around 952-955fps at 150 bars. 

Let me know if we can improve it a bit more since this was the first time that we did something of this sort. Please note that the transfer port was elongated before as well but we tried to replicate your design. 

I'd probably chuck that one and try again with a Dremel + a narrow grinding stone bit.

 

[mtnGhost]

@heavy-impact

Hey! Nice CAD drawing... Is there an open source for those or have you done your own?

https://grabcad.com/library/fx-impact-1#! .. there's probably more out there

 

[wajie316]

Start at the outside making it 7.4mm then make the elongated portion and then smooth the transition between them.

I do this with a li-ion rotary tool and a carbide burr, second one from the right in pic ⑲.

Polish the area last using a felt tip and red polishing compound.

Use low to medium speed when removing metal for best control. Polish at high speed.

Heavy impact,

So we tried to improvise it and we did get around 15fps gain. Its now shooting around 952-955fps at 150 bars. 

Let me know if we can improve it a bit more since this was the first time that we did something of this sort. Please note that the transfer port was elongated before as well but we tried to replicate your design. 

I'd probably chuck that one and try again with a Dremel + a

Start at the outside making it 7.4mm then make the elongated portion and then smooth the transition between them.

I do this with a li-ion rotary tool and a carbide burr, second one from the right in pic ⑲.

Polish the area last using a felt tip and red polishing compound.

Use low to medium speed when removing metal for best control. Polish at high speed.

Heavy impact,

So we tried to improvise it and we did get around 15fps gain. Its now shooting around 952-955fps at 150 bars. 

Let me know if we can improve it a bit more since this was the first time that we did something of this sort. Please note that the transfer port was elongated before as well but we tried to replicate your design. 

I'd probably chuck that one and try again with a Dremel + a narrow grinding stone bit.

I agree. Any idea wat should be the gains in fps that i should expect from transfer port mod only?

 

[edosan]

@heavy-impact you are right about the turns, But you are missing 2 things considering why I said the ER is more efficient.

1- I have made real test in lots of different integrated plenum (40cc) and external plenums (at least 10 different combos) and the combo 20cc external + 20cc integrated, beats in speed (do not remember exactly how much but is noticable) the 40cc integrated only. 

2- Talking with ER the conclusion is that since the external plenum is closer to the VS the air flow got caught by it faster, more direct Flow.

So for experience, is more efficient.

The plenum COMBO Michal (if it works over time, too soon to tell, but looks good) & ER (proven and working on all br events) I will take it any time tho together! I will build a 200fpe impact 

Btw, do not trust those drawings to the letter, they are good but inaccurate in several places. 

 

[heavy-impact]

Threads will be much neater if we delete the pictures when we quote someone.

 

[heavy-impact]

I plan to combine the large eccentric and external as well. I wish I hadn't deleted the CAD drawing I posted for the large eccentric plenum back in April. Mod said it couldn't be restored since I edited it. https://www.airgunnation.com/topic/fx-impact-mods-for-more-fpe/page/15/#post-486520

I'm glad someone produced it though. Huma missed the chance.

 

[mtnGhost]

Two plenums.. hmmm, I guess my plans to switch my MKII to .257 won't be a problem! My question is who's going to be the first with a .50 cal MKII?

 

[heavy-impact]

Two plenums.. hmmm, I guess my plans to switch my MKII to .257 won't be a problem! My question is who's going to be the first with a .50 cal MKII?

I'm pretty sure I'll have a

MKXXXV Heavy-Impacter when the barrels arrive.

 

[edosan]

You don't need to wait for the liner to shoot .30 slugs...here is what a tj barrel do with RatSniper Slugs @ 150meters over the impact ... If I could pull it together living where I live! For you should be much much more easy... You just need to do more and complain less

 

[heavy-impact]

1 out of 2 ain't bad.

 

[Avidrob]

Do i need a Hammer weight, for pressures between 130-165b. is there any benefit, or is the 19.5 gram stock hammer the best? I feel i have quite a lot of Hammer spring tension, so did wonder if a liitle more weight and little less tension would be better? 

Iv just ordered Mikes plenum tube, along with his twin brass inlet and Probe (nice work mike)

Im trying to make my impact more efficient, its currently slinging .25 34gr mk2 at 890 fps, but i need the reg at 165b to get there, (Long story covered in an older thread), I think the 700mm barrel sees to big a pressure drop, so hopfully the bigger plenum will help fix this.

My Valve seat is 6mm, and the brass inlet is ported

Open to input from anybody on how i can improve things

 

[PaniSd]

I had simular issue with my gun when I get it.

First you need to check manometers. If you have FX ... defenetly they are not acurate. Also I believe you dont need 165 for shooting mk2. I belive you have bad setings on your gun.find the Ernest Rowe vodeo about finebtune the gun ... I think is in section of videos on you tube called Master clas. There is so much to be explained so first see the video.

 

[heavy-impact]

Do i need a Hammer weight, for pressures between 130-165b. is there any benefit, or is the 19.5 gram stock hammer the best? I feel i have quite a lot of Hammer spring tension, so did wonder if a liitle more weight and little less tension would be better? 

Iv just ordered Mikes plenum tube, along with his twin brass inlet and Probe (nice work mike)

Im trying to make my impact more efficient, its currently slinging .25 34gr mk2 at 890 fps, but i need the reg at 165b to get there, (Long story covered in an older thread), I think the 700mm barrel sees to big a pressure drop, so hopfully the bigger plenum will help fix this.

My Valve seat is 6mm, and the brass inlet is ported

Open to input from anybody on how i can improve things

Adding hammer weight helps from 145 bar on up with the standard valve size. A larger valve takes more force to open so about 6 grams more weight should do. You need to tune it with the valve stop to keep from opening the valve too long and wasting air.

 

[mtnGhost]

What is the life expectancy of acetyl C3 bumpers btw?

 

[OrdnasNS]

3000+ shots, 6mm OD, cca 2mm thickness, relatively tight fit on valve rod so it does not move from hammer seat and it is the same as when I put it in, no marks, dents, cracks. The head of hammer is 6mm in diameter so it is best to use delrin of the same OD and then there is no way to make indention or to cut it slowly like if it is 8mm and also C3 is always in a same position tight on hammer seat so it does get hitted in a same manner. ID of the delrin is 3mm and then filed to make it tight so it can not move or get tilted, it is always parallel to hamer and the stop so it can not get damaged.

 

[Avidrob]

I had simular issue with my gun when I get it.

First you need to check manometers. If you have FX ... defenetly they are not acurate. Also I believe you dont need 165 for shooting mk2. I belive you have bad setings on your gun.find the Ernest Rowe vodeo about finebtune the gun ... I think is in section of videos on you tube called Master clas. There is so much to be explained so first see the video.

Thanks Panisd

Mine is a mk1, with a few upgrades including 6mm VS and wika guages, so im know the reg readings are pretty accurate.

Re settings believe me when i say, i have tried EVERYTHING possible (as covered in another thread), I have hit the ceiling of max velocity at all my tested reg pressures, Just for clarity this reg pressure will give 920fps with everything wide open, but i dial back the valve stop 890fps to tighten groups and air efficiency

Right now at 890fps im super happy with the SD ES and group sizes, just want to see if i can get the same at much lower pressures. Leaving me headroom for more power for slugs later.

 

[Kikopower]

Today, I found something in the mail box...

Thank you very much @edosan... it is always fun to come back from some holidays and find new toys waiting for you