LPR Input pressure and dwell

[fog]

I just got an LPR, and am playing around with how to set it up best for my marker. I've got a question about how to properly adjust an LPR setup for best efficiency. Here are the directions you can find on the impulse faq as to adjusting an LPR kit-

Set your Impulses operating pressure to 150psi.
2. Set the LPR at its maximum output pressure setting.* This will be 150psi.* We don't really care about the LPR's actual pressure.* We are trying to do this the simple way.
3. With the operating pressure at 150psi, adjust your dwell to get the gun to shoot about 300fps.* This will give you a very good dwell setting to use with the LPR.
4. Now set the operating pressure up to 200psi.
5. Shoot over a chrono, adjust the LPR to get the velocity you want, lets say 290fps for an example.
6. There you are done!

To change your velocity, adjust the LPR.** Leave your dwell and operating pressure set as is.

What I'm not sure about is the 200psi input pressure. Is this a number that was picked with stock internals, or does it take into account aftermarket parts that may be more efficient? (I'm running new designz internals- valve, bolt, and AA brass hammer on a Toxic and an ANS Jackhammer 2 on the vert adaptor) It seems to me that a high input pressure with a high dwell setting (lots of pressure going through a valve open for a long time) would give you worse effiency than a lower input pressure (say 150?) with the same dwell setting. Wouldn't it be better to run lower pressure into the marker for better efficiency, or am I way off? I was thinking of trying to set the gun up with 150psi input, adjust the dwell from the highest, to the point at which the velocity drops off, and then adjusting the LPR. Would this work?

If anyone out there is running an LPR I would be interested in hearing how they set it up, and what kind of effieciency that they are getting out of it (shots per tank), and the other performance details.

[mipaint]

Being the one that orginaly wrote those directions, I'll coment.

1st you have to understand that the amount of ghas required is the product of two factors. The pressure of the gas and the amount of time that pressure is relesed. To say the dwellis the time the pressure is "on" is not realy correct, but the dwell effects how long the pressure is "on".

So to oversimplefy you can push the ball with a long low pressure push or a short high pressure push. The problem with a long low pressure push is that the ball is set in motion. as the ball moves away (down the barrel) the pressure decreeses. because of this, you need more air with the long low pressure push.

Now guys-- those of you that know exactly how this works will take issue with this explination- but remember we are trying to explanin this in a very simple way, so I'm using a bit of liberity with the exact facts.

So anyway, getting back to the real world example. when I use a low pressure on the valve, I have to hang that valve open a longer time to get my 300 fps or so. The advanage of the LPR is to allow you to run the valve at a very high pressure while the lpr runs the solenoid at a very low pressure.

An Impulse can be run at 100 psi with a very long dwell setting. problem is, it will use a lot of air and you will most likly get less then half as many shots as you would at 180 psi. The solenoid is designed to take the very high pressures that would generate the best effeciency, so that is why we use the LPR.

We recomend 200 psi simply because it gives you room to slightly adjust the imput pressure to compsate for conditions without going up to the 230 psi range where the reg starts to vent.

We have a few fokes that are using the after market valves, the High pressure spring in the max flo, and relocating the PRV to the back of the gun. they are using pressures as high as 300 psi (while the LPR keeps the solenoind at less than half that) These guys are getting over 2000 shots for a 68ci tank. Frankly we have guns using the ND valve at 200 psi and the dwell almost shut off getting up in the 2000 shot area too.

FOM

[fog]

Thanks for the reply. I guess I am just trying to figure out in my head the way the impulse works for best effiency, and am trying to weed out the BS I have heard about the dwell and how it works. It makes more sense now. I actually ordered the valve and LPR kit through your site because of the information on it.

[checkyourhopper]

Damn FOM,

That was impressive.

On a side note though, I was reading your response and wondered something. Why hasn't anyone developed a solenoid that can take 200 psi without imploding? You would think that would be the next step instead of always having to design stuff to basically do an end-around the fragility of a solenoid.

[brad2886]

The solenoid can take 200 psi and it would explode, not implode :P

[checkyourhopper]

Not my solenoid.

And I still think implode is the better word because the last time I even approached 200 psi, my solenoid started leaking from the inside something crazy. It didn't really "burst with a loud noise; blow up; detonate" or "burst noisily and violently" as some of the definitions of the word explode state.

And besides, there is still my original point. I'm just curious as to why no one has come up with a sturdier solenoid. I mean, we have upgrades for just about every peice of the marker. Why not a better solenoid that can take, say 250 psi. Then you could really have like a really short dwell with a high PSI so the marker would be more efficient. Not to mention, you would no longer need an LPR setup.

Anyways, just my random thoughts...

[Spec]

how bout with an Evil LPR is it the same thing with other LPR's???

do i have to put it to 200 psi and than go to 300 FPS than adjust from there with the LPR???

[brad2886]

Implode is where high pressure from out goes in, and explode is from in to out... high air passing THROUGH the solenoid would make it explode, since it can not hold that pressure in, it goes out.... therefore explode :D

brad

[checkyourhopper]

Originally posted by brad2886
Implode is where high pressure from out goes in, and explode is from in to out... high air passing THROUGH the solenoid would make it explode, since it can not hold that pressure in, it goes out.... therefore explode :D

brad

No mas. I concede. It's explode. :|