D420! How about that?

[buddhasummer]

Maybe if this version takes off they'll add a wider exhaust on the D420W.

 

[scubadada]

It’s funny they put so much into exhaust, I have never even noticed exhalation effort on a single hose reg, what I do notice is short exhaust not running bubbles out and clear.

Under very heavy exertion, greater at depth, I have definitely been aware of the work of exhalation. Perhaps this can be shown in the WOB loops generated in the ANSTI simulator testing

 

[lexvil]

Under very heavy exertion, greater at depth, I have definitely been aware of the work of exhalation. Perhaps this can be shown in the WOB loops generated in the ANSTI simulator testing

Interesting, I’ve been fairly deep but breathing remained same, as in no thought involved, I still see this as hype to sell regulators to the masses who are afraid to go beyond 100 feet, granted better is better but once we have good enough what difference does it make? I’m sure we could get great numbers if the tee were removed completely or a long tube were added to creat a chimney, like a DH that once started moves exhaust very well. For most buyers of these “consumer” products I think a longer exhaust tee, at least as an option would better serve. I could be wrong.

 

[scubadada]

Under very heavy exertion, greater at depth, I have definitely been aware of the work of exhalation. Perhaps this can be shown in the WOB loops generated in the ANSTI simulator testing

Hi @rsingler

What do you think about my comment regarding work of exhalation?

I'm not talking about comparing regulators. I'm talking about being consciously aware of the work of exhalation while diving a good regulator, at depth, with considerable exertion (significantly increased RMV).

 

[Couv]

I think a longer exhaust tee, at least as an option would better serve.

The problem with putting an exhaust tee over the current setup is that it will change the case geometry. Even though the exhaust valve remains in the same place, once exhaust bubbles begin to flow from the tee, which is now higher in the water column, it will create a lower pressure area over the exhaust valve and consequently inside the case. The lower pressure inside the case will cause the demand valve to open. Even with a straight tee, this will happen with any turn of the head (assuming a normal swimming position.)

 

[buddhasummer]

The deepest I've been is 60m, I noticed zero difference (Apeks), of course I was likely narced off my head. I for one would take a "hit" to WOB in favour of a less bubbles across my mask. Once I notice something it quickly becomes an irritation. In that respect the D is on thin ice.

 

[lexvil]

The problem with putting an exhaust tee over the current setup is that it will change the case geometry. Even though the exhaust valve remains in the same place, once exhaust bubbles begin to flow from the tee which is now higher in the water column, it will create a lower pressure area over the exhaust valve and consequently inside the case. The lower pressure inside the case will cause the demand valve to open. Even with a straight tee, this will happen with any turn of the head (assuming a normal swimming position.)

Sort of my point, the machine doesn’t do these things so personal experience and overall experience make a difference. There are factors that make differences that can’t be tested, like what mask I’m wearing, Friday I switched from my Tusa paragon mask to my back up Atomic frameless, the short tee of the G260 was putting bubbles in some odd way and pushing air into my hood, cold head isn’t nice. This was the first time I noticed the short tee of the 260 after switching from Atomic regulators. A short tee on a safe second for compactness is great but I would like an option of a longer one.

 

[rsingler]

Hi @rsingler

What do you think about my comment regarding work of exhalation?

I'm not talking about comparing regulators. I'm talking about being consciously aware of the work of exhalation while diving a good regulator, at depth, with considerable exertion (significantly increased RMV).

@scubadada , I think you're spot on. It wasn't until I climbed in the pool with four of Scubapro's best that I became aware of it. Like others who have posted, unless you look for it, the feeling the ease of exhalation is very subtle. And the criticisms that the latest tweak on the ANSTI machine are just hype to sell new toys are not entirely incorrect. Most divers are vacation divers in shallow water who don't give their equipment a second thought.
But we are now routinely taking diving to depths that we're never even contemplated outside the military or university institutions in years past. Couple that with accident analyses that shows a chain of otherwise innocuous problems stringing together to make a catastrophe, and you have reason to consider every possible enhancement that you can technically make.
With that in mind, I really think I noticed that the D420 has an easier exhalation. Bubble paths aside, if you put marginal regulators in thick air and add some exercise, you have a potential issue. Or take another possibility: choosing your regulator for bailout on CCR diving. If you bail out to open circuit following a CO2 hit on the rebreather, you want to unload CO2 as fast as you can. And that is a function of both inhalation and exhalation ease of breathing when gas density may be high, you may be panicked, and you're near the end of that accident chain of events.

It seems to me that we have two groups commenting in this thread: one group which is unimpressed with the marginal improvement in capability, and another which is focused on low probability events and marginal equipment improvements.
Both groups are right, for the type of diving that they may do. There's no absolute answer, but for an equipment geek and physiologist like me , who is getting a little older, I'm willing to pay now that I'm heading into the tech realm. I think this equipment tweak is exciting (even if some bubbles occasionally cross my mask).

 

[axxel57]

It’s funny they put so much into exhaust, I have never even noticed exhalation effort on a single hose reg, what I do notice is short exhaust not running bubbles out and clear.

I think that the effort of SP to lower the exhaling effort is due to the fact that WOB is measured on the ANSTI machines as a combination of inhaling and exhaling effort.
Since, I guess, it's technically easier to lower the exhaling effort than to work on a more easier inhaling effort, they decided to concentrate on the exhaling process, even when in practice the exhaling effort hardly ever plays a role, to produce good WOB numbers.....

 

[lexvil]

I think that the effort of SP to lower the exhaling effort is due to the fact that WOB is measured on the ANSTI machines as a combination of inhaling and exhaling effort.
Since, I guess, it's technically easier to lower the exhaling effort than to work on a more easier inhaling effort, they decided to concentrate on the exhaling process, even when in practice the exhaling effort hardly ever plays a role, to produce good WOB numbers.....

I would guess the real problem with the inhalation side is freeflow and how freaked out some people get, just not a good selling point. I like better and I’ll have a 420 hopefully before the next dive. I just got a C370 Mk11 in to play with, it’s exhaust is styled after the 620ti and it does look like a better design but can’t confirm until I dive it.