The New Atomic TFX
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That does look a good bit like the Titanium Nitride coating that I see on drill bits and mills.
Titanium nitride - Wikipedia
My Ti2 octo arrived yesterday. 
My TFX still has not shipped.
My TFX still has not shipped.
That does look a good bit like the Titanium Nitride coating that I see on drill bits and mills.
Titanium nitride - Wikipedia
en.m.wikipedia.org
Yep. I'd bet a dollar that's a TiN coating.
TiN is also commonly used on high-performance motorcycle fork tubes, to make them "slicker" for sliding in and out of the fork tube outers and seals.
OP
The reg set was delivered with a first stage IP at 136psi, and the TFX cracking at 1.3" from the factory.
Sigh.
After opening it up, the reg easily tunes down to 0.5", though the valve seal is a little skittish that low, just like the D400. It consistently seals at 0.7". The knife edge is quite sharp (but you'll have to wait for pics, because I'm intent on another feature right now).
The diaphragm is the same OD as the D400, give or take.
Of more significance, the TFX exhaust valve is clearly larger from the top, and no, it won't fit inside the diaphragm retainer of the D400. So no new substitution into old regs.
Looking underneath, the TFX exhaust pathway is 29.5mm diam ID, compared with 27mm for the D400.
Doing the Pi x r² thing, that comes out to a 19% greater area for exhalation!
When coupled with the low collar of the diaphragm retainer and the multiple exit paths for exhaled gas, it suggested the potential for easier exhalation WOB.
But that didn't prepare me for the actual measured data.
Where my current Atomic and Scubapro regs yielded 0.5" on normal exhalation (out of the water), peaking at 0.8-1.0" with forceful exhalation, I measured
0.3" peaking at 0.5" max with the TFX!!!
Totally unexpected.
But remember, the exhalation valve is lowermost with this design, so in-water performance is...
TBD.
Stand by.
Sigh.
After opening it up, the reg easily tunes down to 0.5", though the valve seal is a little skittish that low, just like the D400. It consistently seals at 0.7". The knife edge is quite sharp (but you'll have to wait for pics, because I'm intent on another feature right now).
The diaphragm is the same OD as the D400, give or take.
Of more significance, the TFX exhaust valve is clearly larger from the top, and no, it won't fit inside the diaphragm retainer of the D400. So no new substitution into old regs.
Looking underneath, the TFX exhaust pathway is 29.5mm diam ID, compared with 27mm for the D400.
Doing the Pi x r² thing, that comes out to a 19% greater area for exhalation!
When coupled with the low collar of the diaphragm retainer and the multiple exit paths for exhaled gas, it suggested the potential for easier exhalation WOB.
But that didn't prepare me for the actual measured data.
Where my current Atomic and Scubapro regs yielded 0.5" on normal exhalation (out of the water), peaking at 0.8-1.0" with forceful exhalation, I measured
0.3" peaking at 0.5" max with the TFX!!!
Totally unexpected.
But remember, the exhalation valve is lowermost with this design, so in-water performance is...
TBD.
Stand by.
Intrigued me enough that I went back to your D-Series service thread. (How to restore a Scubapro D300, D350 & D400: Theory and Practice)
Noting that there was a taller and shorter version of the diaphragm retainer "neck?" ... it implies that a diaphragm retainer with a higher arch might be able to fit in the scrotum and provide clearance for the TFX diaphragm assembly. Possibly a 3D print opportunity for retrofits?
Do you happen to remember the D400 OoW performance that you measured as the mostdirect comparison?
Wait
Wait
Wait ....
Any hints or tips on how to do that adjustment?
I'm a bit disappointed to hear it comes from the factory like that after reading elsewhere that the factory spec for cracking pressure is supposed to be 0.5".
Based on what I know about car engine exhaust valves, I *think* the Pi * r^2 thing is not the right comparison. I think the correct way to compare is by circumference. 29.5 / 27 yields a 9% increase. Still nothing to sneeze at.
That sounds very promising. I am looking forward to a post-dive review. And I cannot WAIT to receive mine! I got just the male portion of that OmniSwivel hose repair kit coming, so I'll be ready to shorten the stock hose right away. And, I guess, check the cracking pressure and adjust that straightaway, too.
Geo7
Contributor
Good point that the cross section of a tube may apply less than the circumference. I'd add to that that the flexibility of the diaphragm will dictate how far it folds open. The more flexible it is, the more the cross section may come into play as well (i.e. the flow increase may go beyond 9%).
Also, the D400 seemed to obstruct the exhaled airflow somewhat with the tall top hat diaphragm retainer. As Rob mentioned, in the TFX there is a straight path for the air (and all directions), and I think that will be noticeable.
Also, the D400 seemed to obstruct the exhaled airflow somewhat with the tall top hat diaphragm retainer. As Rob mentioned, in the TFX there is a straight path for the air (and all directions), and I think that will be noticeable.
OP
I love groupthink!
@stuartv and @Geo7 , you guys are right. It's just like flow at the LP valve of a standard second stage. It's circumference x height of seat lift that determines area for airflow out of the orifice.
scubaboard.com
Better than its inwater performance would have suggested, which tends to lend weight to @stuartv and @Geo7 's observations. Without dense water impeding exhaled gas flow, a D-series OR TFX diaphragm leaflet is free to rise throughout its full circumference, in contrast to a standard reg that may have a) a vertical or horizontal fin designed to keep the valve from folding (which pins perhaps 40% of the total area close to the valve spokes, and b) a possible "floor" in the exhaust tee (again to prevent folding) which limits vertical lift off the exhalation valve.
The D-series and TFX have none of this, allowing (on the surface) very unimpeded flow. Underwater, everything changes. I am guessing that the collar of the diaphragm retainer in the D-series is part of the problem, not to mention the exhaust valve's position lowest in the water column.
The TFX shares the potential issue of a "lowermost" exhaust valve due to its similar configuration. However, perhaps those multiple paths out of the case will allow the valve to perform better than its D400 sister.
BTW, adjustment of the cracking effort is exactly like the D400: just unscrew the top cap with a small pin face spanner and use a standard screwdriver to unscrew the cap which adjusts poppet spring pressure.
The older diaphragm retainers, both tall and short collar, have an ID that is too small to accept the shoulder of the diaphragm where the exhaust valve sits. A 3D printed collar that's just a touch larger might indeed be a solution for a D400 that would allow use of the TFX diaphragm. The configuration of the scrotum on the inside limits an increased diaphragm retainer diameter (see those short spokes), but collar diameter would seem to be unaffected:
But the diaphragm retainer is a very thin plastic piece, and incorporating threading might make it a deal breaker for 3D.
@stuartv and @Geo7 , you guys are right. It's just like flow at the LP valve of a standard second stage. It's circumference x height of seat lift that determines area for airflow out of the orifice.
The D400 that I dived in Brac was 0.6" cracking and 0.3-0.6" exhalation effort out of the water.
D420! How about that?
A lot of divers on the board are hardware fanatics, wanting to extract the last ounce of performance from their equipment. A newer diver would be better to concentrate on ease of use, ease and cost of maintenance, and reliability. Have you read this thread in its entirety? I get the impression...
The D-series and TFX have none of this, allowing (on the surface) very unimpeded flow. Underwater, everything changes. I am guessing that the collar of the diaphragm retainer in the D-series is part of the problem, not to mention the exhaust valve's position lowest in the water column.
The TFX shares the potential issue of a "lowermost" exhaust valve due to its similar configuration. However, perhaps those multiple paths out of the case will allow the valve to perform better than its D400 sister.
BTW, adjustment of the cracking effort is exactly like the D400: just unscrew the top cap with a small pin face spanner and use a standard screwdriver to unscrew the cap which adjusts poppet spring pressure.
The older diaphragm retainers, both tall and short collar, have an ID that is too small to accept the shoulder of the diaphragm where the exhaust valve sits. A 3D printed collar that's just a touch larger might indeed be a solution for a D400 that would allow use of the TFX diaphragm. The configuration of the scrotum on the inside limits an increased diaphragm retainer diameter (see those short spokes), but collar diameter would seem to be unaffected:
But the diaphragm retainer is a very thin plastic piece, and incorporating threading might make it a deal breaker for 3D.
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