Sorry guys, didn't have time to post before. Here goes:
The respirator is, in one way, just another LPR, but with a neat design that does away with external hoses and keeps it all in a sleek package about the size of an Eclipse front cap. However, it's designed to be set up a little differently from other LPRs, in that you are supposed to run the valve pressure higher than normal, and get better efficiency as a result. So for best results, use it in conjunction with the Evil Valve, which is designed for higher pressure operation. Then you can set the valve pressure to somewhere in the 200-250psi range (you might have to move the PRV for this; mine is mounted on the back of the gun, next to the hammer chamber) and set the LPR to something around 100-120psi.
If you don't have the Evil valve, you won't get the best performance at this sort of pressure, so leave the main pressure between 170-200psi. Depending on what reg you are using to feed the gun, and how well it flows, you may get slight dropoff (20-30fps under rapid fire) because the Respirator reduces the capacity of the valve chamber quite a bit.
Start by finding the best Dwell setting, before you fit the LPR, in the normal way - that is, shoot over the chrono, gradually turning up the dwell; when the velocity stops increasing dramatically, turn it back down a click or two and leave it there.
Then fit the Respirator, which involves removing the front plug or tapeworm if fitted, greasing up the o-rings on the nipple and on the body of the reg where they seal against the collar, and screwing it into the front of the body using the flats on the reg body, exposed after you remove the outer casing. I found the two large o-rings that seal the collor really do need a good layer of grease, otherwise one of them will tend to leak.
Adjust the Resp slowly upwards until you can shoot rapidly WITH PAINT without shootdown. When I first set it up, I found that without paint in I could dry fire to my hearts content at 14bps, but as soon as I put paint it it I got dropoff to the point where after 3 shots the balls weren't even making it out of the barrel. Another quarter-turn on the LPR fixed that. You will know as soon as you start really hammering out the paint if you've set the pressure too low, and you'll be cursing the damn thing if (like me, stupidly) that happens on your way to your primary in the first game of the day
Now you've found the minimum LPR pressure, adjust the main pressure and LPR pressure suitably to set the velocity. I start with the Resp set about a quarter to a half of a turn beyond the minimum, then get the velocity close with the main pressure, then fine-tune with the LPR.
Overall, it's a good little reg, and seems quite consistent, as long as the rest of the setup suits it, and you understand how it wants to be set up. The design in itself is neat, since you know you're always going to get shot in the fiddly bits
