Tuning Fx Impact shoots the same speed on each settings: Update

Jump to latest Follow Reply
Redick

Redick

Member
Nov 9, 2019
1,546
26
Ohio, United States
Just picked up a used impact and every setting is the same speed from min to max on the power wheel which is about 900fps. Anyone know the problem? I would like to gradually decrease/increase pressure with every turn of the wheel like it's supposed to operate. 

Fx impact 25 mk1, No Power Plenum 700mm 

Huma Regulator set to 100bar

Valve adjuster is on 3rd line

Huma dual port and probe

Hammer spring has plenty slack i did not measure but it's really loose even on max setting. 












 
It may be that you have a derelin C3 bumper. The original "rubber viton style" had some give in it and my power wheel had a good range of speeds. When I put in the derelin one there was very little if any variation. I confirmed this with FX and they said it is why the factory ones come with a viton Oring there, even though they do wear out in time. I ended up putting a viton one back in and all is well.
 
Upvote 0
It may be that you have a derelin C3 bumper. The original "rubber viton style" had some give in it and my power wheel had a good range of speeds. When I put in the derelin one there was very little if any variation. I confirmed this with FX and they said it is why the factory ones come with a viton Oring there, even though they do wear out in time. I ended up putting a viton one back in and all is well.
Click to expand...

If that's the case then why would the newer style impacts with the C3 still function as normal with the PW as well as some others who upgraded. Just doesn't make any sense. 
 
Upvote 0
Could be the C3.

Could be that reg pressure is too low so the HS is overpowered on every setting.

Check your HS pre-load adjustment by holding the hammer adjuster against the power wheel and rotate the power wheel with your other hand. If set properly, the hammer adjuster should barely move when you change the power wheel from Min to E or 1.

If the previous owner backed the hammer adjuster screw out too far it could be that the power wheel is not engaging at any setting.
 
Upvote 0
Could be the C3.

Could be that reg pressure is too low so the HS is overpowered on every setting.

Check your HS pre-load adjustment by holding the hammer adjuster against the power wheel and rotate the power wheel with your other hand. If set properly, the hammer adjuster should barely move when you change the power wheel from Min to E or 1.

If the previous owner backed the hammer adjuster screw out too far it could be that the power wheel is not engaging at any setting.
Click to expand...

Bingo Jbravo I think you just nailed it. I just checked the wheel and there's no movement at all
 
Upvote 0
"If that's the case then why would the newer style impacts with the C3 still function as normal with the PW as well as some others who upgraded. Just doesn't make any sense."

Just trying to be helpful. I have an Impact X in .22. When my original C3 _"bumper"_ bit the dust, the gun lost velocity and sounded a bit hollow. FX sent me 2 types of C3's, a derelin one and a couple of original ORings. When I put in the derelin one my MAX setting velocity went from the original 895 to 910 fps. There was very little velocity differences in the wheel settings. FX said that was why they didn't ship with those. When I put back the original style my wheel velocities went from 740 on MIN to 905 on MAX. (I don't know if the newer versions ship with the derelin one like you seem to indicate.)

With my gun uncocked, if I hold the adjuster against the wheel and turn the wheel, there is no movement between MIN and 1, from there the adjuster moves to the left with each increase in numbers all the way to MAX. Your's should too if you want the spread of velocities between settings. I could probably give that screw a turn for more speed but JSB 18.13's just work too well at 875 to change anything. Good Luck!
 
Upvote 0
"If that's the case then why would the newer style impacts with the C3 still function as normal with the PW as well as some others who upgraded. Just doesn't make any sense."

Just trying to be helpful. I have an Impact X in .22. When my original C3 _"bumper"_ bit the dust, the gun lost velocity and sounded a bit hollow. FX sent me 2 types of C3's, a derelin one and a couple of original ORings. When I put in the derelin one my MAX setting velocity went from the original 895 to 910 fps. There was very little velocity differences in the wheel settings. FX said that was why they didn't ship with those. When I put back the original style my wheel velocities went from 740 on MIN to 905 on MAX. (I don't know if the newer versions ship with the derelin one like you seem to indicate.)

With my gun uncocked, if I hold the adjuster against the wheel and turn the wheel, there is no movement between MIN and 1, from there the adjuster moves to the left with each increase in numbers all the way to MAX. Your's should too if you want the spread of velocities between settings. I could probably give that screw a turn for more speed but JSB 18.13's just work too well at 875 to change anything. Good Luck!
Click to expand...

Thanks for the help I wasn't stating what you said didn't make sense. I was stating the c3 issue didn't make sense. I'm starting to think its the C3 for sure now.

I opened the Valve past the 4th line and went up to 110bar on the reg shot over chrony and speed went from 900 to 950. I then adjusted the valve back down to 915. Now after all the madness the HS adjuster is working as it should but the speed still doesn't change using the HS only using the Valve. So on Min to Max setting its pushing a 25.39 pellets at 915fps on 110bar. I'm getting a silly amount of shots on this setting ill tell you that much almost 100!!!

Valve-9.84mm

HS-20.12mm
 
Upvote 0
You may want to check out your hammer and spring as well it could have a heavy hammer weight or spring shims installed. That could also account for the type of problems you are having as well.

I had the same problem with my Impact when I installed a smallish brass spring spacer/hammer weight. I was able to just turn down the HS adjuster to get back most of the adjustment on the power adjuster wheel though.
 
Upvote 0
You may want to check out your hammer and spring as well it could have a heavy hammer weight or spring shims installed. That could also account for the type of problems you are having as well.

I had the same problem with my Impact when I installed a smallish brass spring spacer/hammer weight. I was able to just turn down the HS adjuster to get back most of the adjustment on the power adjuster wheel though.
Click to expand...

I'm friends with the previous owner so I asked what all he had done to it. He assured that he only did the huma upgrades nothing else so I don't know. I guess I will start from scratch to see what happens. Bio..Remember the hammer spring started out loose with no adjustments in speed shooting 900 already so that keeps making me believe it might be that C3. Wierd..lol these impacts are🤯
 
Upvote 0
I was pmed about it, I honestly dont think there's anything wrong with the gun. It can be tuned to act like this.

MK1 no power plenum running at a low reg pressure (100 bar), valve knob between second and third line making 45fpe.

Of course more hammer spring than minimum wont add power as it's basically maxed out at that reg pressure and being limited in travel by the valve adjuster.

Open that valve adjuster up and voila more power.

The thing about the HST tension preload screw was strange. I think it would be remedied but running at a more MK1 reg pressure for .25. (120-130 bar) then the HST wheel will work as it's intended. It's been tuned like a PP model low reg pressure. But being neutered by the valve adjuster being between 2-3 line (no dwell)

My opinions only.
 
Upvote 0
I was pmed about it, I honestly dont think there's anything wrong with the gun. It can be tuned to act like this.

MK1 no power plenum running at a low reg pressure (100 bar), valve knob between second and third line making 45fpe.

Of course more hammer spring than minimum wont add power as it's basically maxed out at that reg pressure and being limited in travel by the valve adjuster.

Open that valve adjuster up and voila more power.

The thing about the HST tension preload screw was strange. I think it would be remedied but running at a more MK1 reg pressure for .25. (120-130 bar) then the HST wheel will work as it's intended. It's been tuned like a PP model low reg pressure. But being neutered by the valve adjuster being between 2-3 line (no dwell)

My opinions only.
Click to expand...

I'm going to try that method Glem. I'm going to open the valve up all the way, turn back the HS and up the regulator pressure and see what happens. 
 
Upvote 0
Reduce HS until you see speed drop.
Click to expand...

HS was already loose and was not operating as stated in my initial post. I then turned HS in until it started to function properly. The only way the speed will decrease is with the valve adjuster. I'm starting to think the C3 as the OP first stated might be the problem.
Click to expand...




what’s the HS measurement at max or min? I forgot to mention that your regulator is a bit high also. For reference when my gun came from Utah airgun the regulator was at 90 bars and hammer spring was no where near all the way(sorry forgot exact measurement) and at setting 3 the exact king was shooting 920 FPS. So it’s very possible even at the lowest possible hammer force the the speed can’t go lower with 100bar regulator pressure. Reduce your reg to 90 or 85 and you should see your hammer spring power setting start working again. Keep in mind the impact with PP is very powerful, it’s practically silly powerful when it comes to lighter pellets. I had my reg at 80 and still shoot hades at 900+ FPS with HS barely half way. If you want to shoot at lower speed you need to be at 80 bars and HS way down.
 
Upvote 0
Reduce HS until you see speed drop.
Click to expand...

HS was already loose and was not operating as stated in my initial post. I then turned HS in until it started to function properly. The only way the speed will decrease is with the valve adjuster. I'm starting to think the C3 as the OP first stated might be the problem.
Click to expand...




what’s the HS measurement at max or min? I forgot to mention that your regulator is a bit high also. For reference when my gun came from Utah airgun the regulator was at 90 bars and hammer spring was no where near all the way(sorry forgot exact measurement) and at setting 3 the exact king was shooting 920 FPS. So it’s very possible even at the lowest possible hammer force the the speed can’t go lower with 100bar regulator pressure. Reduce your reg to 90 or 85 and you should see your hammer spring power setting start working again. Keep in mind the impact with PP is very powerful, it’s practically silly powerful when it comes to lighter pellets. I had my reg at 80 and still shoot hades at 900+ FPS with HS barely half way. If you want to shoot at lower speed you need to be at 80 bars and HS way down.
Click to expand...

Is yours a MK1?
 
Upvote 0
Reduce HS until you see speed drop.
Click to expand...

HS was already loose and was not operating as stated in my initial post. I then turned HS in until it started to function properly. The only way the speed will decrease is with the valve adjuster. I'm starting to think the C3 as the OP first stated might be the problem.
Click to expand...




what’s the HS measurement at max or min? I forgot to mention that your regulator is a bit high also. For reference when my gun came from Utah airgun the regulator was at 90 bars and hammer spring was no where near all the way(sorry forgot exact measurement) and at setting 3 the exact king was shooting 920 FPS. So it’s very possible even at the lowest possible hammer force the the speed can’t go lower with 100bar regulator pressure. Reduce your reg to 90 or 85 and you should see your hammer spring power setting start working again. Keep in mind the impact with PP is very powerful, it’s practically silly powerful when it comes to lighter pellets. I had my reg at 80 and still shoot hades at 900+ FPS with HS barely half way. If you want to shoot at lower speed you need to be at 80 bars and HS way down.
Click to expand...

Is yours a MK1?
Click to expand...




doh, didn’t see OP has MK1. However I’ll still be shocked with 700mm barrel OP needs 100 bars to get 26 grain pellet to 900fps.....then again I could be wrong 
 
Upvote 0
Ok fellas Glem got me in the ball park. I now have control of the power wheel. The issue was too low of a regulator pressure again to much HS & valve tension. Now on to tuning for what I intended for a backyard low power high shot count squirrel smacker
Click to expand...

Excellent, keep us updated as to how you're liking it. Should have a great shot count in that setup.

👍
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu