Importance of Tuning 1st stage with particular 2nd stage?

[tbone1004]

@tbone1004 you're pretty much echoing what I said. A 2nd stage can be set to whatever you want it to be. Octo or not. That said a typical "shop tuned" octo will have a higher breaking point. As for the better flow out the bottom? I assure you a machine can tell as it's one less 90 degree turn vs side exit. You or I would not be able to tell.

show the results from a test like that. It's one thing to measure total flow which obviously is going to be higher thru that port, but it has been proven that the LP ports individually can flow more gas than the tank valve. In measuring total work of breathing or cracking pressure at any human capable breathing, there will be no difference.

 

[Timmy V]

Fluid dynamics. My daytime job involves HVAC design and "bend losses" are real. I am not arguing whether or not there's anything noticeable. I am simply stating that you will have less "loss" flowing out the bottom.

 

[Andrew Dawson]

Yeah, I imagine a flow meter would be able to tell a 90 degree bend in flow vs one without.....however, I probably would not. I also do not have the data to back up my opinion, tho....stranger things have happend!

This has been super informative and helpful. I very much thank everyone's time, expertise, and wisdom!

 

[StefinSB]

Fluid dynamics. My daytime job involves HVAC design and "bend losses" are real. I am not arguing whether or not there's anything noticeable. I am simply stating that you will have less "loss" flowing out the bottom.

If it is not noticeable it’s a mood point isn’t it.

 

[Timmy V]

A question was asked. I answered it

 

[ams511]

I would recommend purchasing an ip gauge to check the intermediate pressure of the first stages if you are concerned. They are inexpensive. As far as the bottom port goes I know some manufacturers claim this is a high flow port, for example Oceanic and Kirby-Morgan. However I agree with tbone that you will not be able to tell the difference. Divers like the bottom port because it helps with hose routing.

 

[buddhasummer]

I have multiple first and second stages, I set ip to 140 on them all and tune seconds accordingly so mixing and matching is never an issue. I have a couple of unbalanced seconds that would give me issues when combined with a MK17 due to its rather large ip swing, sold it.

 

[Eric Sedletzky]

I don’t think anybody would be able to tell the difference between the bottom port and side ports. I think It’s humanly impossible to be able to breathe enough volume fast enough to begin to get anywhere close to the limitations of a 90 degree turn. We’re not filling tires off it at full unimpeded flow.