13xx Max Smoke Pro Valve

[Tack Driver 10]

Took the Max Smoke valve and with a little coaching took it "Pro".
Modified the exhaust end by moving it close to the exterior of the valve.
This reduces volume and streamlines the exhaust path.
The big question is, "What effect will this mod have on performance?"

[Buldawg76]

Very cool. Sure it will help but not by how much.

BD

[Long_Gun_Dallas]

Took the Max Smoke valve and with a little coaching took it "Pro".
Modified the exhaust end by moving it close to the exterior of the valve.
This reduces volume and streamlines the exhaust path.
The big question is, "What effect will this mod have on performance?"

Looks like you'll lose power overall, but will still have a decent amount with much less piston strokes. 

Curious to see the results.

[Tack Driver 10]

Assembled the gun using my mod mule gun.
It has a BackPacker tube, a front mounted 90D poly seal on the piston and a NOS 766 modified pump link.
Should be able to test in the morning, rained all day.

[Tack Driver 10]

Ran the gun over the chrony:

18" Barrel with 7.9 CPHPs:
05 pumps 524 FPS  04.82 FPE 
07 pumps 611 FPS  06.55 FPE 
10 pumps 728 FPS  09.30 FPE 
12 pumps 775 FPS  10.53 FPE 
15 pumps 835 FPS  12.23 FPE 

Decent power but this valve has more volume than my normal valve so a 24" barrel was tested:

24" Barrel with 7.9 CPHPs:
05 pumps 565 FPS  05.60 FPE 
07 pumps 661 FPS  07.66 FPE 
10 pumps 766 FPS  10.30 FPE 
12 pumps 813 FPS  11.60 FPE 
15 pumps 872 FPS  13.34 FPE 
18 pumps 938 FPS  15.43 FPE

Started retaining air at 18 pumps.
Was still making 20 FPS per pump through 18 pumps though.

A good rule of thumb is 22 cal will yield about 150 FPS less than 17 cal at the high end.
So at 18 pumps should produce close to 800 FPS in 22 cal?
That would be around 20 FPE so..............
Installed a 20" 22 cal barrel and will test in the next few days (when it warms up a bit).

[Tom Tucker]

Nice numbers.  Really awesome numbers, actually.  What was it doing before?

With the .22 cal, my guess is that 20 FPE at 18 pumps is possible, but it would need a very heavy pellet to do it.  I think it will be closer to 18 FPE at 18 pumps with 14.3's.

[Tack Driver 10]

Nice numbers.  Really awesome numbers, actually.  What was it doing before?

With the .22 cal, my guess is that 20 FPE at 18 pumps is possible, but it would need a very heavy pellet to do it.  I think it will be closer to 18 FPE at 18 pumps with 14.3's.

I don't have an apples to apples comparison but with a balanced valve installed in the same gun  (13xx SHO) it made similar power.
I didn't test it with a 24" barrel though, just the 18" barrel.
https://www.gatewaytoairguns.org/GTA/index.php?topic=153687.msg155691545#msg155691545

My 1366 gun was recently upgraded and made almost identical power with a Challenger barrel.
It has a 4.2" stroke and the max smoke valve so should have done better.
It topped off a little lower at 910 FPS with 18 pumps.
https://www.gatewaytoairguns.org/GTA/index.php?topic=157738.msg155747213#msg155747213

The throat on this valve is .220" and the TP opening is .170" so probably better suited for 22 cal.
I may make another valve ported for .177 cal with a gauge.
Should get to test this gun later today.

[Tack Driver 10]

Put the 22" Crosman 22 cal barrel on the gun and tested:

22" Barrel with 14.3 CPHPs:
05 pumps 444 FPS  06.26 FPE
07 pumps 518 FPS  08.52 FPE
10 pumps 609 FPS  11.77 FPE
12 pumps 650 FPS  13.41 FPE
15 pumps 715 FPS  16.23 FPE
18 pumps 761 FPS  18.39 FPE

Was hoping to make 19+ FPE but .........
Dropped off some at 18 pumps, possibly ran out of gas.
22 cal is about 55% greater volume so more valve volume could help.

Put a 14 1/2" barrel on and tested:

14 1/2" Barrel with 14.3 CPHPs:
05 pumps 428 FPS  05.82 FPE
10 pumps 584 FPS  10.83 FPE
15 pumps 675 FPS  14.46 FPE

For comparison:
The 13xx gun with the balanced valve made 598 FPS, 11.35 FPE with an 18" barrel and 10 pumps.

[Long_Gun_Dallas]

That's some great numbers!  Do you have increased piston stroke?  I've worked mine as best as I can manage with normal stroke.  I can get 555fps at 15 pumps w/16gr and 14.5" barrel.  I've seen far worse and far greater results. (Than mine).  I can only wish I had tools to experiment as you are.

How does the volume on your valve compare to a normal one?  It looks like it would be smaller? 

[Tom Tucker]

Very cool setup.  I think the combination of the parachute seal on the piston and the check-seal being flush with the face of the valve is what makes this setup so efficient and able to perform so well with what appears to be very little valve volume.  You must be generating a lot of pressure...

Since you have to the tools and the know-how, I wonder if you ever tried making the piston seal out of PTFE?

[Tack Driver 10]

That's some great numbers!  Do you have increased piston stroke?  I've worked mine as best as I can manage with normal stroke.  I can get 555fps at 15 pumps w/16gr and 14.5" barrel.  I've seen far worse and far greater results. (Than mine).  I can only wish I had tools to experiment as you are.

How does the volume on your valve compare to a normal one?  It looks like it would be smaller?

Since this gun is using a Backpacker tube the stroke is the same as a stock 13xx gun, 3 1/2".
The valve volume is smaller than a stock valve but I don't know by how much.
A FT valve and piston and some light valve work should get you around 550 FPS with 14.3 CPHPs and 10 pumps.

[Long_Gun_Dallas]

Since this gun is using a Backpacker tube the stroke is the same as a stock 13xx gun, 3 1/2".
The valve volume is smaller than a stock valve but I don't know by how much.
A FT valve and piston and some light valve work should get you around 550 FPS with 14.3 CPHPs and 10 pumps.

That sounds about right.  I've only ever had one valve I've worked with, and it was hogged out before I got my hands on the gun.  I think I'm going to have a go at reducing the volume forward of the inlet valve.  Maybe by moving it forward as you did.  And reduce internal volume as well.  Thanks for the feedback

[Tack Driver 10]

Very cool setup.  I think the combination of the parachute seal on the piston and the check-seal being flush with the face of the valve is what makes this setup so efficient and able to perform so well with what appears to be very little valve volume.  You must be generating a lot of pressure...

Since you have to the tools and the know-how, I wonder if you ever tried making the piston seal out of PTFE?

I wish I would have put a gauge on this valve.
It really helps to know what the pressure is when testing.
I'm guessing since it's retaining air at 18 pumps the pressure is around 2500 PSI.
I might take the gun apart and make a few more valve mods to it along with a gauge.

The piston seal, close tolerance check valve along with the HD pump link really packs the air in.
The Delrin valve stem releases really easy at high pressure also.

I have PTFE and made a few test seals but found that it's not very resilient and is difficult to get a good seal.
Most 13xx tubes are stamped and it telegraphs through along with out of round issues etc.
It would work well with a high quality tube.
James Perotti made some parachute seals from Teflon with great success.
   

[Tack Driver 10]

We've all heard the cliche "less is more", so with that in mind.......
I made a new valve based loosely on the Max Smoke Pro valve with significant mods.
It'll have reduced volume, smaller porting, new seal technology and a gauge.

The new version will be called, the "Min-Max Smoke Pro Valve". (try saying that 3 times fast...LOL)
The throat is reduced from .220" to .187" and the port is .155", formally .170".
Coupled with the reduced volume, should allow higher pressure without retained air.

Moved the seal forward to reduce dead air and added a gauge.
Assembled the test gun and pressure tested it last night.
11 pumps 2000 psi
14 pumps 2500 psi

With the reduced volume this valve will be geared for 17 cal and a shorter barrel.
I have a 24" barrel on it now and hope to test it later today.

[rsterne]

Must be a lot smaller volume than a stock valve.... I was only getting 1200 psi at 11 pumps with an FTP, and it took 22 pumps to reach 2000.... and about 38 to reach 2500....



With a stock pump piston, the pressure maxed out at about 1300 psi, no matter how many pumps.... 

Bob

[Tack Driver 10]

Must be a lot smaller volume than a stock valve.... I was only getting 1200 psi at 11 pumps with an FTP, and it took 22 pumps to reach 2000.... and about 38 to reach 2500....



With a stock pump piston, the pressure maxed out at about 1300 psi, no matter how many pumps.... 

Bob

Probably less volume than a 13xx stock valve.
A 2100 valve has the least volume maybe less than this one.
It only has about .200" stem travel before the stem hits the check.

Chrony results with 7.9 CPHPs and 17 cal 24" barrel:

05 pumps 580 FPS  05.90 FPE 1000 PSI
07 pumps 677 FPS  08.04 FPE 1300 PSI
10 pumps 785 FPS  10.81 FPE 1950 PSI
12 pumps 837 FPS  12.29 FPE 2250 PSI
15 pumps 883 FPS  13.67 FPE 2600 PSI (full dump)
18 pumps not tested

Averaged about 15+ FPS more than the Max Smoke Valve across the string.
Didn't test 18 pumps since the results started to top off at 15 pumps.
Might try a 10" barrel with 10 pumps to see how close it can get to 700 FPS.

[Tack Driver 10]

Another day, another valve mod.
Took the Max Smoke Pro valve and bolted on a new front end.
The original used the standard o-ring configuration. (that's so yesterday.....LOL)
This new version incorporates forward seal technology coupled with the new wide mouth bass mod.
I'm calling this new valve "The Max Smoke Pro Billy Bass Edition".....LOL
It's part of my "Zero Tolerance for Dead Air Initiative".

[Tom Tucker]

You are having more fun than you should be allowed to have.

LOL.

I've been trying to build a 1322 that will do 10-10-10.  10 FPE, 10 pumps, 10-inch barrel.  I think you're pretty much there, or slightly above...

[Tack Driver 10]

You are having more fun than you should be allowed to have.

LOL.

I've been trying to build a 1322 that will do 10-10-10.  10 FPE, 10 pumps, 10-inch barrel.  I think you're pretty much there, or slightly above...

What power are you getting now with what mods?

10³ is doable with a 10" barrel in 22 cal.
I ran the gun with a 10" 17 cal barrel yesterday and it got 693 FPS, 8.42 FPE using 7.9 CPHPs.
With a little valve volume tuning I think it could make 10 FPE in 22 cal, definitely with heavy pellets.
It would need to make 561.2 FPS with 14.3 CPHPs.

I'm knocking on the door and hopefully me and "Billy" will bust the door down soon.

[Tom Tucker]

I have one that does 9.0 FPE at 10 pumps, 10-inch barrel.  Flat-top piston.  Delrin piston with oil wiper, Viton 75D o-ring and Nitrile 90D back-up ring.  Flat-top valve.  90D Nitrile O-Ring 1.7cc volume, short check valve with dowel pin, shaped poppet, narrow stem, ported exhaust, o-ring sealed stem.  5/32" ports.  This one might do better with a metal piston.

Another one is doing 9.4 FPE at it's best, but it uses a brass piston with a Crosman pump cup and it needs an oil wiper because it drops down to 8.5 FPE as the cup gets dry.  Same valve mods as the first one

The last one is doing 10.7 FPE with an 18-inch barrel.  Similar to the first one, but with an aluminum flat-top piston and 90D poly o-rings, valve is bored to 2.4cc, and 11/64" ports.  I don't think this one would do very well with a short barrel because of the large valve volume.