breathing effort difference between 2 first stages...help

[JKSteger]

I have an Oceanic PX3 first stage and a Dacor Viper America first stage.

My brother got me a HOG 2nd stage (thanks bro). I hooked it to my LP hose and tried it out...in the garage! It breathed "Good". I then took all the hoses and such off the Oceanic PX3 first stage and moved everything over to the Dacor Viper first stage.

WOW! what a difference! The 2nd stage seemed to breath "Extremely well", very fluid and smooth!

I moved everything over a few times to test and the result was the same every time.

Now what I'm wondering is this, does the IP's of the first stage effect how fluid and smooth the 2nd breaths? Or is this because the Viper has something called a DFC port that the primary 2nd is attached to?

Think a tech could get the PX3 to breath as "smooth" as the Viper? I'm a little hesitant as I would like to get one of the 5 LP HOG regs, specifically the D1. But if I can get my current Oceanic PX3 to breath super sweet, fluid and smooth as that Viper, or dare I say even better, then I will save my money on the HOG first for now.

So what do you all think? Is the PX3 an entry level and I should upgrade anyway?

Thanks,
Jeremy

 

[Nemrod]

Yes, IP can certainly be a factor. Internet diagnosis of such things can be a challenge, make sure both firsts are set to the same IP, notice also the IP drop and recovery of each. Hoses same diameter and length? N

 

[Jimmer]

Check the IP on both first stages. Also, I'll bet adjusting the second stage to match the PX2 would make a noticeable difference. If the second stage was shipped from HOG tuned for an IP of say 145 psi, but your PX2 is putting out 135, it will perform differently.

 

[redacted]

I'm surprised you could notice any difference. Time to record some data, like IP and cracking pressures.

 

[halocline]

It's got to be differences in IP, unless something's wrong with the oceanic.

 

[JKSteger]

Thanks everyone, I'm going to just take them to the shop. Yes Nimrod, same everything except the 1st stages. And yes AWAP, there was a difference. A quick inhalation on the new HOG was not as smooth as my old Scubapro Balanced Adjustable that was setup with the Oceanic. That is why I tried moving everything over to the Viper just to check.

I will take it to the shop and tell them that I need the Oceanic and HOG matched for "fluid smoothness".

Thanks,
Jeremy

 

[Couv]

Hello Jeremy,

Before you trek down to your LDS, have a look at this checklist the Usual Suspects put together.
http://www.scubaboard.com/forums/4320058-post14.html

For the entire thread, you can start here:
http://www.scubaboard.com/forums/regulators/260452-regulator-checklist-inspection.html

Good luck,

Couv

 

[TSandM]

Nice checklist, couv! I have bookmarked it.

 

[herman]

Assuming the HOG is a balanced second stage...and I think it is, unless the IPs of the first stages are a lot different - 40/50 psi or more - which they should not be or there is some other problem with the Oceanic you should not be able to tell the difference between them. 10 or 20 psi difference in IP should not be user detectable on a balanced second stage unless there is problems in the second stage. If the HOG happens to be unbalanced then 10 or 20 psi in IP will make a difference.

 

[halocline]

Herman, I don't agree with that. It's true that a balanced 2nd is less reactive to IP differences than an unbalanced, but a 20 PSI difference would definitely be noticeable. You still have a mechanical spring pushing the seat closed; I would venture a guess that most balanced barrel-poppet regs have about a 50% downstream bias. It would be easy to measure a SP s-wing poppet for seat diameter (actually orifice interior diameter) and diameter at the balance chamber end with a micrometer and calculate the surface area of each.

A few PSI, I definitely agree, would not be noticeable on a balanced 2nd, and I also agree that the difference is likely to be much more pronounced on an unbalanced 2nd, which this one could be. In fact, I looked up the HOG website and this is the 2nd stage that came up, it does not say balanced so I would assume it's unbalanced.

http://www.edge-gear.com/HOG_SECOND_STAGE_REGULATOR_p/3090.htm