Umarex "Umarex Notos Update HUGE power Upgrade!" Or is it?

So Firewalker cut and crowned an FX liner for my 380mm barrel kit from C88machining. I also ordered c88's plenum and plenum extension. I already had a gauge block from Wes @ Airgunarcheryfun.ca and decided to keep it on there.
Man oh man, it was close to not fitting but it fits.
3D867061-DEB4-412D-BDFC-D8DBCEA75518_1_105_c.jpeg


Moderator is close to the airtube but doesn't touch, about 1mm of clearance.
6F9BBD1D-5C36-46A6-904E-815EE585F71E_1_105_c.jpeg


Overall length is now 36-1/2" as I use it with the stock extended and a Donny FL Tanto on the end. And it still feels light!
It weighs, as you see it, 5lbs 1oz according to my kitchen scale. Scoping it will put it over 6lbs but will be worth it.

Here is the kit laid out as I got it from Firewalker after he cut the barrel and assembled the kit for testing.
He and c88machining both did a great packing job on the parts.

55458D29-440B-4FFE-85FA-5C8785F52714_1_105_c.jpeg


Just did some testing and it looks like I gained 50 fps while still having 4mags before I drop off the reg. Nice!
CPHP were doing 825fps for 21.6 FPE and are now going 875fps for 24.32 FPE. H&N Slug HP .218 were going 675fps before and now are going 730fps.
Without a re-zero while doing chronograph testing, I was hitting my spinner about an inch up and to the left.
Finding accuracy should be a breeze.
Famous last words, lol.
 
So Firewalker cut and crowned an FX liner for my 380mm barrel kit from C88machining. I also ordered c88's plenum and plenum extension. I already had a gauge block from Wes @ Airgunarcheryfun.ca and decided to keep it on there.
Man oh man, it was close to not fitting but it fits.
View attachment 461099

Moderator is close to the airtube but doesn't touch, about 1mm of clearance.
View attachment 461100

Overall length is now 36-1/2" as I use it with the stock extended and a Donny FL Tanto on the end. And it still feels light!
It weighs, as you see it, 5lbs 1oz according to my kitchen scale. Scoping it will put it over 6lbs but will be worth it.

Here is the kit laid out as I got it from Firewalker after he cut the barrel and assembled the kit for testing.
He and c88machining both did a great packing job on the parts.

View attachment 461102

Just did some testing and it looks like I gained 50 fps while still having 4mags before I drop off the reg. Nice!
CPHP were doing 825fps for 21.6 FPE and are now going 875fps for 24.32 FPE. H&N Slug HP .218 were going 675fps before and now are going 730fps.
Without a re-zero while doing chronograph testing, I was hitting my spinner about an inch up and to the left.
Finding accuracy should be a breeze.
Famous last words, lol.
Nice!
STOP!
Your making me want the exact same set up!
 
I’ve got a plenum ready to be threaded if usps does their part tomorrow. I suppose we’ll see. Appreciate the analysis 👍. Hopefully have some numbers soon. I have a feeling this thing's going to need a bigger boat….. I mean tank, lol.

Dave

Look forward to your results so I can do some comparative analysis with my formulas/spreadsheet. Hope you go big on that new plenum! Lol.

-Matt
 
I'm
I’ve got a plenum ready to be threaded if usps does their part tomorrow. I suppose we’ll see. Appreciate the analysis 👍. Hopefully have some numbers soon. I have a feeling this thing's going to need a bigger boat….. I mean tank, lol.

Dave

Running a .48L bottle on the big gun!
 
The usps came through but the die cut an undersized thread so I ended up single pointing it on the mini lathe. The tap was fine though. I made the plenum from an inline filter housing. It brought my volume up to 21cc total.

My reg set point kept coming up as the reg was breaking in (I assume), so I had to adjust it down a bit. Pressure before each shot is listed. The original 2600 test was around 2620, now it’s a little lower, hopefully the reg will settle.

It has quite a bark with the short barrel.

Obviously the faster shots are with 14.3gr and the slower are 25.4

Dave


IMG_5867.jpeg
IMG_5862.jpeg
 
Running the reg that ‘high’ is just a random number to experiment with. 2600 isn’t that high to me. If you consider an unregulated gun, the initial point is a lot higher. To make power with short barrels, higher pressure is a way to do that.

This gun is only an experiment and will undoubtedly be tuned way back. A lighter hammer will be tested at some point as well. Something to do inside during this rainy season here.

Dave
 
@sb327 - What's the reason for having the reg so high? I was wondering if your creep is related.
Are you running a stock barrel and just a plenum?
And yes, stock barrel with added plenum, with my other mods I mentioned earlier in thread.

The set point change may very well be from the higher setting. Keep in mind though, I’m probably one of the few who have actually measured the output of the factory regulator and I’m doing it with a digital gauge which is overly accurate for most applications. If it’s cool outside, just holding the plenum in your hand will warm it up and make a decent pressure jump.

Dave
 
And yes, stock barrel with added plenum, with my other mods I mentioned earlier in thread.

The set point change may very well be from the higher setting. Keep in mind though, I’m probably one of the few who have actually measured the output of the factory regulator and I’m doing it with a digital gauge which is overly accurate for most applications. If it’s cool outside, just holding the plenum in your hand will warm it up and make a decent pressure jump.

Dave
Nice! I just went back and looked at your other mods. (y)
I was trying to up power while maintaining shot count but I didn't get near the power increase you have for obvious reasons.
Looks like it's time to do some porting and see if I can find the happy medium of fps and shot count....
 
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Running the reg that ‘high’ is just a random number to experiment with. 2600 isn’t that high to me. If you consider an unregulated gun, the initial point is a lot higher. To make power with short barrels, higher pressure is a way to do that.

This gun is only an experiment and will undoubtedly be tuned way back. A lighter hammer will be tested at some point as well. Something to do inside during this rainy season here.

Dave

I'm running 2500 psi on my 700mm Notos. I'll go higher in the future but I need a tap and a good reamer first.
 
Nice! I just went back and looked at your other mods. (y)
I was trying to up power while maintaining shot count but I didn't get near the power increase you have for obvious reasons.
Looks like it's time to do some porting and see if I can find the happy medium of fps and shot count....

The good news is that you can up the power by porting.

The bad news is that once you port it, your shot count will always be lower.

Part of the Umarex engineering was its outstanding balance of 750 fps with a good shot count for such a small tube. Once you open it up, you create a larger plenum within the receiver itself and that air will always leave the gun when you pull the trigger.

Back to the good news: Hammer weight, hammer spring and preload spring are tuneable! You may find as did I that using a softer hammer spring gives you more velocity with a the gun ported.
 
I’m looking at the real estate available between the valve and barrel and I think there is plenty of room to put a choke in there. I’m not the most knowledgeable on this type of tuning but in conversations with Matt, it helps with es when going lower on a tune. Maybe he can talk me into or out of a tp adjuster. Keep in mind, this is only experimental fun.

Dave