GTA
Airguns by Make and Model => Evanix Airguns => Topic started by: rkr on December 15, 2014, 02:20:15 AM
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This forum has provided me some great information and advice so I think it's time to give back some. A tuning guide for 9mm Evanix guns. These principles can also be applied to larger and smaller calibers. You can check my actual tuning thread http://www.gatewaytoairguns.org/GTA/index.php?topic=58699.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=58699.0) for photos and shot strings.
.357 Evanix Blizzard / Rainstorm II tuning steps by Riku:
This text assumes that you have good working knowledge of PCP airguns and that you know what you are actually doing. I take no responsibility what so ever when you ruin your gun by following these instructions. The text is based on the notes I took when I step by step tuned my Evanix blizzard to 200+ fpe power level.
First examine your gun and make sure everything is in good working order. Check that all the ports are lined up, valve housing to the transfer port and barrel port to the transfer port. If there are misalignments fix these first and make sure that there’s enough room to the o-rings when you drill out those ports. In some cases you may need to grind the port to oval shape first and then drill through to avoid hitting those o-rings. Read through the steps required for each power level and carefully consider whether you are ready and capable of taking all those steps needed. We all want 200 fpe but it takes a lot of work, perhaps 150 fpe is enough for you after all?
These steps can be applied to the new “Sniper/ML” platform as well. It is worth noting that they have longer valve housing and improved sidelever so you may be able to drill through a bigger transfer port (for .45 and .50 guns, .357 max recommended barrel port width is 7mm) and use the existing sidelever.
1. 200 joules / 150 fpe
a. Drill out the barrel port, transfer port and valve housing opening to 6.5mm. You can leave the empty valve housing in place and drill through to the valve tunnel to ensure that everything is lined up.
b. Smooth out the transition from valve tunnel to the valve housing outlet, you should have a completely smooth and round 90 degree bend channel in there. Watch out the valve seat while doing this.
c. Open the valve housing inlet to 9mm size and leave out the valve spring.
d. If you want flat power curve swap out the stock spring for a stiff double spring combo. 12mm OD 1.5mm wire innerspring and 15mm OD 1.5mm wire outer spring. The stock spring will still deliver highest power.
e. Make a support plate for the lower attach point of the sidelever fastening screw
2. 250 joules / 180 fpe
a. Drill out the barrel port, transfer port and valve opening to 7mm and replace the rear barrel holding set screw with a M8 set screw. This will get you very close to the o-rings in the barrel and valve housing so be careful and take it one step at the time.
b. Open up the valve tunnel to 8mm diameter.
c. Smooth out the transition from valve tunnel to the valve housing outlet, you should have a completely smooth and round 90 degree bend channel in there. Watch out the valve seat while doing this.
d. Make a new valve seal, Ertalyte is the material I recommend but PEEK will also work although it’s harder to make seal.
e. Open the valve housing inlet to 10mm size and leave out the valve spring.
f. If you want flat power curve swap out the stock spring for a stiff double spring combo. 12mm OD 1.5mm wire innerspring and 15mm OD 1.5mm wire outer spring. The stock spring will still deliver highest power.
g. Make a support plate for the lower attach point of the sidelever fastening screw
h. Make a new heavy duty sidelever
3. 270 joules+ / 200+ fpe
a. Drill out the barrel port, transfer port and valve opening to 7mm and replace the rear barrel holding set screw with a M8 set screw. This will get you very close to the o-rings in the barrel and valve housing so be careful and take it one step at the time.
b. Open up the valve tunnel to 8mm diameter.
c. Make the valve housing outlet oval in shape, 8mm long and 7mm wide so it just fits in between those valve housing o-rings
d. Make the barrel port oval in shape, 8mm long and 7mm wide
e. Drill open the receiver bottom in between valve housing o-rings with 7mm drill, tap and thread for M8 set screw that will later be used to block the hole.
f. Using a long dremel bit with big ball head open up the bottom of the transfer port to oval shape so it matches valve housing outlet
g. Using a long dremel bit with big ball head open up the top of the transfer port to oval shape so it matches valve barrel port. Smooth out the transition between these two oval ends ensuring an area that corresponds 7.5mm round hole throughout the transfer port
h. Smooth out the transition from valve tunnel to the valve housing outlet, you should have a completely smooth and round 90 degree bend channel in there. Watch out the valve seat while doing this.
i. Make a new valve with a stem narrowed down to 2.4mm in the tunnel area. Ertalyte is the seal material I recommend but PEEK will also work, although it’s harder to make seal.
j. Open the valve housing inlet to 10mm size and leave out the valve spring.
k. If you want flat power curve swap out the stock spring for a stiff double spring combo. 12mm OD 1.5mm wire innerspring and 15mm OD 1.5mm wire outer spring. The stock spring will still deliver highest power.
l. Make a support plate for the lower and higher attach points of the sidelever fastening screw
m. Make a new heavy duty sidelever
n. If you did it all correctly the hammer has now trouble pushing the valve open. Make a heavy tophat that fits inside your spring and hammer. I used a 18 gram tophat in my gun.
o. At this point the stock barrel length is starting to limit the the power and opening the valve for longer periods of time only wastes air. Consider swapping to a longer barrel, each extra inch will give you roughly 10fps extra speed. With 28” barrel you are looking at 220+ fpe and may even hit 240 fpe with heavy bullets.
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Thanks!
I not only bookmarked this but I printed it to PDF to keep in my files.
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I like your shot version of the long thread
thank you
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I like your shot version of the long thread
thank you
Thanks! As an afterthought, if you are power hungry it's better to start with the Sniper platform. The breech is sturdier, it has room for bigger transfer port and heavier spring. The sidelever can take at least 270 fpe without issues and the barrel can be left free floating as the breech supports it better. As a bonus you can get the X2 model with CF bottle which makes for a light gun with decent shotcount.
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Good write up Riku.
One thing I have noticed, it's not the bliz barrel that limits power, I have made 285fpe on that same barrel in an inline valve gun. It's the design that limits output, too long path from valve to barrel and too many corners.
Nice of you to cover the tuning in steps, really helps people on tuning aspect and what to expect.
Marko
Edit: didn't notice how old the original post was..
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Good write up Riku.
One thing I have noticed, it's not the bliz barrel that limits power, I have made 285fpe on that same barrel in an inline valve gun. It's the design that limits output, too long path from valve to barrel and too many corners.
Nice of you to cover the tuning in steps, really helps people on tuning aspect and what to expect.
Marko
Edit: didn't notice how old the original post was..
Well, it's the Blizzard/RS2 barrel that limits the power when we consider the flow limitations in these guns. Sure you can get more power with inline valve and bore size porting, unfortunately inline valve is not possible with these guns. Even a bore size porting would take a lot of work and custom valve housing to make it happen, sure it would give some 20-40 fpe extra power but at that point it is easier to swap in a longer barrel for roughly the same gain in power. I think many owners of these .357 Evanixes are happy to just shoot JSBs at 900+ fps which is what the 150 fpe tune is for.
Edit: It is interesting that you got 285 fpe. Some one said that each 90 deg bend reduces flow some 10%. If we take in to consideration those two bends in the airpath the power would drop down to 230 fpe and the size difference in porting (I assume you had bore size porting) would drop the power to around 200 fpe which was the point where my gun hit the limit with stock barrel. With longer barrel I got well over 230 fpe and for me that was the easy alternative as I also got rid of that crappy original barrel. Of course there's also the fill pressure to play with if you invest in better air tube but I guess we don't have to go to that.
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Yeah, that's what I wrote, 5-10% depending on the turn radius. And I did use bore size porting, right after the most restricting part that is the valve, there the port is bigger to flow more faster.
Marko
Edit: forgot fill pressure was 200bar
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Yeah, that's what I wrote, 5-10% depending on the turn radius. And I did use bore size porting, right after the most restricting part that is the valve, there the port is bigger to flow more faster.
Marko
Edit: forgot fill pressure was 200bar
Oh it was you who stated that, sorry - I didn't recall it. Anyway, around 10% seems to be a close match to real life. If higher pressure is desired, the CF bottles that Evanix uses have 250 bar rating.
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Hello rkr
what color Ertalyte did you used?
there is white and black?
thank you
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Hello rkr
what color Ertalyte did you used?
there is white and black?
thank you
I used white one. Color shouldn't really matter but all seals I've seen have been made of the white stuff. Also known as PET-P.
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ok thank you