Setting Up the Venturi...
- My Titan II conversion came with two ports in the second stage. The primary port is supposed to point directly into the inhale horn to give the best Venturi effect. The secondary port is 180 degrees pointed in the opposite direction and is supposed to create some back pressure to keep the Venturi from Free Flowing out of control. Here are some photos showing the primary port alignment.
(If you look in the shadow under the lever, you can see the secondary port)
(Looking into the horn you can see the primary port pointing directly outward in the center)
With the mechanism positioned this way, I installed the diaphragm, screwed the top onto the can and hooked up a hose to the inhale horn but not the exhale horn. With the air turned on, I took a breath and the regulator went into a hard free flow. This was with a Voit mouthpiece. Next I tried it with a DSV mouthpiece. I got the same hard free flow but I could tell the DSV was tempering it.
I wondered if maybe the lever was adjusted a bit too sensitive. So I backed it off a 1/4 turn. That didn't work so I backed it off another 1/4 turn. Still made no difference. At this point, I forgot to adjust the screw back to where it was.
So I went looking for some other cause. And I found that the secondary port was partly blocked by the first stage nut.
(This photo shows the secondary port is almost touching the first stage nut)
I didn't want to drill another secondary port without being sure it was needed. So instead, I re-positioned the primary port so it was pointing about 1/2 into the inhale horn and 1/2 into the can. This was hoping to create more back pressure and it worked. I closed everything up again and this time I got a very good result. Easy breathing and no free flow. So I took it to the local pool to see how it worked under water. And it was great. But then it started getting harder and harder to breathe. When I took it home and looked inside, it was the lever I had loosened up... The darned nut had almost completely backed off and the lever was barely opening the seat at all!
(This was my set up for pool testing... Used the EPDM hoses and DSV mouthpiece)
Okay so it looked like it would have worked if I had re-secured the lever. But aiming the primary half on and off the horn would be kind of a touchy way to adjust the Venturi... And would not take advantage of pointing the Venturi directly into the horn. I talked it over with Vance and he advised to drill a 1/16th inch secondary port 90 degrees from the primary. This made a definite difference. Still pretty sensitive with the Voit mouthpiece. But the DSV mouthpiece made the Venturi contollable. I gave a slower breath and the venturi free flow went slower. Vance said if I was going to use the Voit mouthpiece I should drill another secondary port across from this latest one. And this seems to have done it. With the Voit mouthpiece, I get easy breathing but no Venturi Free Flow.
I didn't make it to the pool last Sunday but I worked on some final touches. I changed the nut on the second stage lever... used an old style DAAM nut and put some thread locker on it. I also installed some of those pressed in nuts that Rob sells for the plastic cans... So now it screws and unscrews just like a Kraken. I restored my original gray hoses and blue Voit mouthpiece. And I have to say, THIS IS A VERY NICE REGULATOR!