Bypassing the JSA SS valves Balanced feature .... Now high flow conventional

[Motorhead]

Disclaimer .... This is Not an approved or discussed modification with anyone at JSA. 

This simple modification is a BYPASS of the valves Balancing feature having it operate as a conventional valve with a Cobra chamber. Reason for is I run REGULATED on all my PCP's and the SS valve in stock form GREAT as it is unregulated simply was not satisfactory to my requirements while trying to run it regulated

. So to not have this excellent valve sitting unused went about doing the simple modification of manufacturing a new poppet / stem that did away with the balance function. Now the SS valve is ( Not to drop names .. but have too ) is now very similar to a WAR Cobra valve.
* Returning the valve to Balanced operation is a simple as a poppet / stem swap. use the supplied spring & required jet size.

Picture #1
Shows the "Balanced" poppet/stem with vent hole between stem at throat and secondary step in poppet head. ( Top of image )
In the middle ( Ref only ) is a WAR valve poppet from a pre-cobra valve.
Bottom is my custom poppet from PEEK with a poly o-ring to seal within the cobra chamber tube.

Picture #2
My PEEK poppet as it sits within the Cobra tube.
* Did taper the end of tube slightly to reduce any turbulence.

Picture #3
The intake side of the SS valve where I used a countersink in a hand drill and placed small flairs on each hole to reduce intake turbulence & smooth flow.


How does it work ? .... Excellent making equal power to the WAR Cobra valve it replaced.

NO .. Am not going to sell these poppets but only sharing what to do in bypassing a design feature & still use the valve at near full power potential.



Scott

 

[ackuric]

Good job on finding a work around to make the valve function without having to scrap it entirely. I've thought about running a similar cobra style setup just to see if there is benefit in the poppet flow as it seems by design to be better than your conventional setup. I would run mine without the jet as I run a really large plenum and don't see large pressure drop that would really benefit from it.



I would love to see a comparison of a valve setup with the poppet spring + head hidden from air flow like the cobra but unjetted, and then one setup 100% conventionally with spring and poppet head exposed to air flow, to verify if there is any benefit in that aspect. Might be 1 fps, might be 10, but I am sure its gotta be something. Using the same valve but just swapping the internals would aid in keeping the test conditions consistent. 



-Matt

 

[Motorhead]

One thing we do know is the laminar flow the tube provides. Without the air tumbling in and threw the poppet spring coils and the flow that feed the valves throat once poppets up off the seat is far more efficient coming from ONLY the side of the poppet head and not tumbling over it.

The whole premise of Cobra tech is keeping the PRESSURE to AREA the same bearing down on poppet as it is up off the seat. By isolating the pressure drop around the poppets head as valve essentially dumps we keep intact a stronger pressure head within the tube to quickly close it.

The screw in jet & its orifice size control how much pressure can escape the tube while pressure in around poppet head collapses faster.





Scott

 

[ackuric]

I understand the Tech behind the Cobra valve. I personally see less than 100 psi drop over most my shots which is only 5% of my pressure, IMO the Cobra valve REALLY shines in guns that have large 10-20% pressure drops during the shot...now if it can be proven then there are gains to be had with the Cobra tube creating more laminar flow that would be pretty awesome...I suspect it to be more likely true than not, its just a matter of how much the peak fps increases in comparison to the same valve without the tube. 

-Matt