With the earlier Phoenix, it seems to be beneficial to use the higher IP as long as the second stage can handle it. The IP recovery (time for the IP drop to rebound during inhalation) in the earlier Phoenix is comparable to the original RAM, which is very good, but it seems to work better with the higher pressures.
We have found that the IP recovery is much quicker with the second generation Phoenix. With the more constant IP (of the second generation Phoenix) we have found that the performance increase from having a very high IP is less noticeable. Then in turn, by being able to drop the IP a bit, it makes the regulator a bit more reliable (less likely to have free flows).
Nemrod wrote:
it does not seem to have that initial push it had before the HPR install.
I think that to get the effect you are looking for you need to play with the venturi adjustments. By partially blocking the small side air vents (bleed air) you can adjust the amount of venturi flow assistance.
Just a word of warning, the production units are very close to an ideal balance in the venturi flow (the side bleed holes are a bit smaller than the prototypes). Therefore, blocking only a small amount of bleed air ports will increase the venturi a lot.
With the production units I am using one flat washer on one side (not blocking that bleed air port at all) and one cup washer on the other side. I cut the cup washers in a diagonal so that can rotate the washer and only partially block that bleed air port. I have found that only blocking about half of the bleed air port provides the right amount of venturi flow.
Note: my definition of “right amount of venturi flow” is a fairly aggressive venturi flow without being wildly out of control. This may be too much for most divers.
Keep in mind that venturi flow will be a bit higher with the denser air at depth. With the venturi flow finely tuned, I have found an increase in venturi flow in dives deeper than 60ft or more.
The picture below shows the cup washers cut in a diagonal. This is a picture of the prototype (I will take some new pictures when I have a chance), but it shows the cup washer.
Note: adjusting the cup washers to only partially block the bleed air port is a bit of a hassle, since the washer tends to rotate while tightening the screw, but it can be done with a bit of patience.
Just go slow with the adjustments… or you are going to get more “push” than bargain for.