Tuning Umarex Notos has arrived.

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Ezana4CE said:
@Firewalker So What's going on in this photo? Is that an additional 3D printed moderator affixed to the factory moderator? I've been loosely following this gun this year and I like some of what I've been reading about it. I'm still not too familiar with it though. I've found some decent info on how to install the moderator from post #s 490, 512, 530, but where'd you get the moderator?
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Where did you get the moderator? @Firewalker
 
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Dkubany86 said:
Where did you get the moderator? @Firewalker
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I carry the moderator insert as well as a screw on version by Big Air called the "Long John".

20240628_171515.jpg
 
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Hi all, I am Nikos, new to this forum and I need your help @Firewalker and/or any other experts, as I am confused with my Notos behavior. I have added a plenum and drilled all holes to 4mm. I set the regulator at 4/5 of a turn counterclockwise, used the stock hammer spring with 3mm preload and filled the gun to 3,500 PSI. I used the jsb 13.43gr and I could not get more than 870 fps which is the same result I got with the regulator at almost half a turn on a previous occasion. Now the weird thing which I can not explain and I need your advice, is that when the pressure on the gauge dropped to around 2850 psi the fps started rising up to 925 fps and continued at 915-925 until the regulator dropped to 2450 psi and below that the fps started decreasing as naturally expected. I repeated this procedure once more and I got the same results. So what do you guys think? How can this happen, is it something that can be explained or there's something wrong with the regulator or something else? Thank you for any advice on this issue.
Nikos
 
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Nikoum said:
Hi all, I am Nikos, new to this forum and I need your help @Firewalker and/or any other experts, as I am confused with my Notos behavior. I have added a plenum and drilled all holes to 4mm. I set the regulator at 4/5 of a turn counterclockwise, used the stock hammer spring with 3mm preload and filled the gun to 3,500 PSI. I used the jsb 13.43gr and I could not get more than 870 fps which is the same result I got with the regulator at almost half a turn on a previous occasion. Now the weird thing which I can not explain and I need your advice, is that when the pressure on the gauge dropped to around 2850 psi the fps started rising up to 925 fps and continued at 915-925 until the regulator dropped to 2450 psi and below that the fps started decreasing as naturally expected. I repeated this procedure once more and I got the same results. So what do you guys think? How can this happen, is it something that can be explained or there's something wrong with the regulator or something else? Thank you for any advice on this issue.
Nikos
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This is a common issue of a weak hammer spring. The 3500psi has even more area to push against making the hammer spring even less able to push the poppet out of the way so that the air can be sent down the barrel.

Now you have a conundrum to deal with. You will need to change out the poppet to a peek one and get a stiffer hammer spring to open the poppet. The problem is that you will waste air, loose efficiency and stress the cocking handle. You need to drop the regulator setting down, perhaps 2000psi and slowly open it little by little until it plateaus.

With the OEM barrel, 925fps is very respectable, you will need a longer barrel to get 1000fps with your gun.
 
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