Pressure-Compensating and Balanced regs

[UTDragun]

what exactly are these two and what are the pros and cons of each?

[cledford]

I know AKA and now STD (what a stupid name for a company) are heavily into this - but don't know much about it myself. I do know that the original SCM mod was a temperamental pain to setup and someone once did the math and determined that even if it did work that the median impact was so minimal that a human wouldn't be able to notice. That leads me to believe it’s an over engineered means (read more likely to fail or have issues) to do the same thing that a normal LPR does – oh, and make your wallet lighter as a side-effect.

I'd be interested in knowing more but will currently classify it all as BS hype by Aaron Alexander, intended to sell overly complex LPRs when the normal ones work just fine.

If anyone wants more info do a search in the PBN cocker forum - there was a very technical thread there - a second might exist in AKA forum.

-Calvin

[Steelrat]

Geez Cledford, that was a pretty nasty snipe at Aaron. I don't think anyone ever claimed massive benefits from it, but for those people looking for the Nth degree of performance, the pressure compensating SCM and the like deliver it. Why not try to advance the technology? There is a lot of crap out there that costs nearly as much, and frankly, if you don't like the price, don't buy it.

And, for the record, I've never had a problem with an SCM, and I've owned a lot of AKA markers. You just have to remember to adjust up, not down.

[cledford]

Yeah, it was a little harsh, but Aaron/STD/AKA have been known to make some nice claims with nothing to back it up. I think that the Viking/Excal are still the nicest ram based markers out there - but there were even claims made there that wern't backed up. Aaron, like everyone else, is subject to be called out. I would have liked to have seen some hard numbers from him as there were a couple of well thought out questions regarding the SCM that were never addressed.

I should add that aaron is more than smart enough (unlike a lot of those out there hawking the "newest" cutting edge advancement in PB tech) to back his claims up with decent math/proof - if he so chose. Unlike a lot of others he has the training, education and ability - but I've never seen it and don't understand why. That makes me wonder, especially when AKA/STD tends to run twice the cost of "normal" tech goodies.

-Calvin

[WenULiVeUdiE]

what exactly are these two and what are the pros and cons of each?

Pressure compensating basically means the output pressure of one reg (LPR) will not change if the output pressure of it's air source changes. Many DM3 owners had to constantly deal with this. They cange their HPR pressure and would have to adjust their LPR to compensate.

I think the claim that it is overly complex is alittle off base. It does lead to inconsistancy or anything. There is less maintenance to do on the pressure compensating SCM-2 than there is to do on a non-compensating Timmy or Cyborg or Matrix (etc.) LPR.

cledford- Any examples of where Aaron needed to back himself up? I know Larry did spew abit of hype with the Excalibur and such. To my knowledge, Aaron has never made any public claims.

[rkjunior303]

Yeah, it was a little harsh, but Aaron/STD/AKA have been known to make some nice claims with nothing to back it up. I think that the Viking/Excal are still the nicest ram based markers out there - but there were even claims made there that wern't backed up. Aaron, like everyone else, is subject to be called out. I would have liked to have seen some hard numbers from him as there were a couple of well thought out questions regarding the SCM that were never addressed.

I should add that aaron is more than smart enough (unlike a lot of those out there hawking the "newest" cutting edge advancement in PB tech) to back his claims up with decent math/proof - if he so chose. Unlike a lot of others he has the training, education and ability - but I've never seen it and don't understand why. That makes me wonder, especially when AKA/STD tends to run twice the cost of "normal" tech goodies.

-Calvin

i tihnk dan backed up his LPR perfectly fine when he demonstrated its flow capabilities when he hooked it up as an inline reg with a viking on full auto.

[FallNAngel]

i tihnk dan backed up his LPR perfectly fine when he demonstrated its flow capabilities when he hooked it up as an inline reg with a viking on full auto.

Yes, but that's flow. It has nothing to do with pressure compensating measures.

On a traditional, non-pressure balancing regulator, as the input changes, the output changes inversely. Basically, as one goes up, the other goes down. How much the swing is depends on the regulators ratio. For instance, I think Sidewinders have a 70:1 ratio. This means as the input changes by 70psi, the output will change by 1psi.

For example, let's say your tank has 4500psi in it and the marker is set at 200psi. You shoot 3500psi from the tank. If the tank reg has a 30:1 ratio, then 3500 / 30 = 116psi increased pressure to the marker . 116 / 70 = 1.65 decrease in operating pressure. If the LPR is only a 30:1 ratio... well... 1.65 / 30 = 0.055psi increase. Not a lot of change.

Granted, the ratio of the tank reg and LPR in the example above are just numbers I picked off the top of my head... but I think you get the idea. For the most part, a good inline regulator is really what you need, not a pressure compensating LPR.

[Pneumagger]

just as a sort of comparison...what are the typical LPR ratios for both pressure compensting and balanced types?

What are the typical ratios for inline regulators and tank regulators for that matter?

[FallNAngel]

Good question, honestly I have no idea.

I know the Palmer Stabilizer and Sidewinder *should* be 70:1. I believe the Fatty Stabilizer is 90:1

Past that, I'm not sure. Most tank regs aren't really all that high from what I'm told, as they're made for flow, not consistency over the pressure range of the tank.

Honestly, I think having a pressure compensating LPR and a poor HPR is a bit pointless. You're better off getting a good HPR and just not worrying about it. You'll have better consistency in the long run and if it's a pressure compensating HPR, you shouldn't have many fluctuations in the LPR anyway.

If I had the option to do it all over again, I'd get a Palmer LPR instead of my STD LPR for my Freestyle.

[Steelrat]

If I had the option to do it all over again, I'd get a Palmer LPR instead of my STD LPR for my Freestyle.

Why?

[FallNAngel]

I had a problem with my STD reg piston pinching the piston o-ring. It happened once or twice at home and I thought it was me... then it just happened on the field as I was just standing there. Ended up having to send in the LPR to STD to have it worked on. It hasn't happened since then, but I have near zero tolerance for things like this. Same reason I've thought about selling my Cheetah board. If they can't ensure they have a fully working product when it leaves the door, should I really be using their product?

Past that, the Palmer LPR (from what I hear) has a better range of adjustment... ie. A 1/4 turn adjusts the pressure less on a PPS LPR than an STD LPR. Thing is, STD got to the market first, so that's what I went with. When it works, it's peachy... since getting it back, I haven't had any problems.

[Steelrat]

Frankly, Palmer makes darn good stuff, I wouldn't mind either LPR.

[tyrion2323]

My experiences with AKA and STD have all been very positive

[nicad]

"Pressure-Compensating reg" and "Balanced reg" are both terms for the same thing.

In a reg, you want a high as possible ratio (which can be either inverse or direct, depending on the reg design), but you also want a large as possible reg seat so that it will recharge as fast as possible with minimal seat movement ("fast response"). The larger the reg seat, the lower the ratio or the larger the reg body has to be to maintain a higher ratio.

In theory balanced pin regs do not have a ratio (or it is oo:1), so you can have as large a reg seat as you want and not have to worry about the other parameters.
Typically, however, most "balanced" regs are still slightly un-balanced-- they use the "partially-balance" compensation to help fight for a high ratio AND large reg seat.

The Evolve Pi is a 100% balanced reg.
The 2Liter is a partially-balanced reg.

[Steelrat]

I think AKA has tended to advertise the recharge rate of the 2 liter more than it being balanced. How well does the pi do when it comes to recharge and flow?

[AzrealDarkmoonZ]

The PI is fully balanced?

Az

[nicad]

I have not had much time to test the Pi. So far, it seems about par with an old Stabilizer I have had around forever. I would guess it should recharge faster, but have not really had the time to pay with it.


Yes it is fully balanced. Input pressure has no directional force effect on the seat pin.

[UTDragun]

"Pressure-Compensating reg" and "Balanced reg" are both terms for the same thing.

In a reg, you want a high as possible ratio (which can be either inverse or direct, depending on the reg design), but you also want a large as possible reg seat so that it will recharge as fast as possible with minimal seat movement ("fast response"). The larger the reg seat, the lower the ratio or the larger the reg body has to be to maintain a higher ratio.

In theory balanced pin regs do not have a ratio (or it is oo:1), so you can have as large a reg seat as you want and not have to worry about the other parameters.
Typically, however, most "balanced" regs are still slightly un-balanced-- they use the "partially-balance" compensation to help fight for a high ratio AND large reg seat.

The Evolve Pi is a 100% balanced reg.
The 2Liter is a partially-balanced reg.
so the ratio shows the rate at which the pressure changes over the course of emptying a tank, but how would you measure consistentcy of the output during high rates of fire?

so which tank reg would you reccomend then? I have 04 conquest, max-flo and a apoc2k. Conquest needs a rebuild, max-flo doesnt work, and the apoc needs a rebuild and i cant find parts for it

[Ydna]

I was skeptical about the Pi balanced reg before it came out. I had thought about a similar setup but was worried about there being no lift on the piston. But they made it work well using design factors that they traditionally employ on their other stuff, it's a worthy system.

[AzrealDarkmoonZ]

Doesn't the PI use the adjustable reg seat type system, though in this case a stem with orings, Ion regs, CPs, and Sidewinders have used other adjustable reg seat options?

Which should make them immune to input pressure changes but is that the same as balanced?

Az

[Ydna]

The general shape is the same except it doesn't use a "seat", rather a balanced piston (two o-rings of the same size aroudn the input port). So when the air is shut off the piston will only be moving in one direction due to the output air, and the input has no bearing on it in either state.

Here's a model I made http://www.zdspb.com/media/tech/regs_pi.JPG

Like nicad said just about any other reg is technically unbalanced in some direction, but it's small enough that it can be chalked up as a marketing statement...

[AzrealDarkmoonZ]

Input pressure should have no change to a sidewinder regulator either though? Correct? The unbalancing comes from the small pin in most regulators that has air behind it so has the input lowers generally the output increases, whereas in a adjustable regseat that should be a problem since the only force the piston is acting against is the washers/springs in the regulator and it just seals against a reg seat, stem with orings, ect.

Whereas a 2liter's piston is not balanced against the input pressure but the output pressure thus the pin is balanced between pushing the spring and the output pressure.

Hrmmm, or does the PI stem float inside the piston? I did not take the one I had apart while I was testing it.

Az

[Ydna]

On a sidewinder the air won't make much difference if the reg seat is fully broken-in, when the piston is closed. The only surface area that would effect any change would be anything with an upward bias....the bottom of the piston is curved so it'll be exposed if the seat isn't deformed to accept it, but once it is it'll be negledable.
http://www.zdspb.com/media/tech/regs_sidewinder.JPG

For the sake of babling I'd not hesitate to mention even a reg that isn't broken in won't make much difference either. Same thing goes for most other moving base regs...for instance an Ion regulator will always have a small bias upward on the piston when the seal is shut off, but it's only as big as the area made by the input port in the bottom (difference of about 1 pound of upward force per 100 psi input pressure). Compare that to the nearly 300 pounds of downward force on top of the piston (when reg set to 160-psi output) that balances out with the spring.

[AzrealDarkmoonZ]

Just to throw out some more random babbling ;)

The Pi Reg did exceptionally well when I was sent a prototype a while back. So much so that it rivalled the 2liter. I was impressed. And the few gripes I had, such as the adjustment screw being some insanely small easy to strip size have now been fixed.

http://www.ppog.org/results.htm

Az