Poseidon - xtream vs Jetstream

[roughwater]

Hi Guys,

I was just wondering if anyone here has had any experience with both these regulators, and is able to give me a comparison on both?

Originally I thought that they may have been similar, but upon further investigation it would appear as though they run on a different line pressure.

Both are upstream regulators (compared to normal 'downlstream').

I'm assuming that Jetstreams aren't intercompatible with xtreams (mixing 1st and 2nd stages because of the difference in line pressure).

I have heard that Jetstreams will freeflow when at a low enough pressure.

I was just wondering if anyone could comment on:

a) What differences they've experienced between the two.

b) Which one would be the better regulator to go with if starting from scratch

c) In regards to free flowing - how low does the pressure get on each (xtream and jetstream) before freeflowing occurs?

d) Can xtream first stages be tweaked to give LP for 2nd stages and vise versa if needed?

e) Anything else that I should be aware of?

I've used Jetstreams before, but not the xtreme.

Cheers

Roughwater.

 

[tfsails]

I'll take a shot at these questions. I've never dived with a Poseidon, but I've rebuilt lots of 'em, so here goes (I'm doing all this from memory; no books in front of me, so apologies if I'm wrong about something):

A) First stages are considerably different, but both are balanced diaphragms. Xtreams have nominal IP of around 125psi, while Jetstreams run around 140. Second stages are virtually identical, with the workings of the Jetstream physically longer than the X, but operating identically.

B) Pick one; they're both good

C) Once tank pressure gets lower than IP, there's not enough pressure to inflate the balloon inside the second stage, so it will free flow.

D) Not sure what "LP" means in this context. Can't help you here

E) They're good regs, but you need to be sure you can get them serviced by someone who knows what he's doing and has the proper tools. A whole lot of Poseidon stuff is proprietary and will only work on Poseidons.

IMHO, the Xtream is just a smaller, modernized version of the Jetstream.

 

[Eau_Girl]

Roughwater,

Can't answer all of your questions and tfsails has answered some of the more technical questions.

I bought XStreams in April 2004 when I first started diving. I did all of my training in the UK and we used Poseidon Cyclones in the OW course. Lots of people I was diving with then had Poseidons.

I've never experienced the problem with them freeflowing when the pressure in my tank is low. I haven't ever run out of air completely and only gotten down to about 20bar (300psi?) when messing around at the end of a dive.

My understanding is that the XStreams were originally designed for the tech market and they then introduced a rec version 2nd stage plus octopus.

I do like them. However tfsails is right you need to have them serviced by someone who knows how to service Poseidon regs and can get the right parts.

I just had mine serviced by Poseidon in the UK. Service was £40 plus parts of £18 plus VAT of 17.5% on top of that.

The one thing I find annoying is that you have to educate dive crews on how to vent your regs when they fill tanks between dives. They always press on the cover and do not realize the purge buttons are on the side. I had an overzealous Fijian dive guide tear up the rubber cover on the first stage which made screwing and unscrewing it onto the tank very difficult. That cost another £22 on this latest service. I'm usually pretty firm about not having people mess with my gear, but things happened quickly and I couldn't stop them.

 

[911964t]

I'll take a shot at these questions. I've never dived with a Poseidon, but I've rebuilt lots of 'em, so here goes (I'm doing all this from memory; no books in front of me, so apologies if I'm wrong about something):

A) First stages are considerably different, but both are balanced diaphragms. Xtreams have nominal IP of around 125psi, while Jetstreams run around 140. Second stages are virtually identical, with the workings of the Jetstream physically longer than the X, but operating identically.

B) Pick one; they're both good

C) Once tank pressure gets lower than IP, there's not enough pressure to inflate the balloon inside the second stage, so it will free flow.

D) Not sure what "LP" means in this context. Can't help you here

E) They're good regs, but you need to be sure you can get them serviced by someone who knows what he's doing and has the proper tools. A whole lot of Poseidon stuff is proprietary and will only work on Poseidons.

IMHO, the Xtream is just a smaller, modernized version of the Jetstream.

Is it true than a poseidon xstream and jetstream have different 1st stage thread sizes? What for to if this is true.

 

[sea_ledford]

I have personal Jetstreams, and my dive program has a fleet of X-streams. The current versions of the two regs have the same first stage, and have for at least the last 15 years. Both have the same IP.

Servicing will be the same between both, although the xstream, for some reason only poseidon can explain, has a plastic tip on the xstream servo valve stem vs the all metal one on the Jetstream. If the purge button is pressed too hard, too many times, the servo valve will get bent in the x-stream and will need to be replaced, and it'll breathe horribly until that happens. That part is NOT included in service kits. I'm still on my original servo valve in my Jetstream from 2010.

Both breath the same as far as I could tell, there might be some differences when put on a test bench though.

X-stream is smaller, lighter and more fragile. Jetstream is a little larger, and more robust. But if you drop it, you'll crack the grating over the purge section (it'll still work fine though).

The freeflow starts at about 50-100 psi remaining pressure. Low enough that it's hard to determine what the actual pressure is based on an SPG. It probably changes depending on how much use the valve insert (the balloon) has. But you are basically out of gas, just getting some warning before you are completely SOL.

If I were choosing between the two, I would go Jetstream every time. Simply due to the stupid plastic tipped servo valve.

ETA: if you are looking at older versions, the first stages may be different and may have different IPs. Depends on the age of the reg you are looking at.

 

[Bigbella]

I'm assuming that Jetstreams aren't intercompatible with xtreams (mixing 1st and 2nd stages because of the difference in line pressure).

No, the two regulators are basically the same -- thirteen years out . . .

 

[BoltSnap]

13 year old thread, how nostalgic

 

[Bigbella]

No scheiß?

 

[p_kos]

I have personal Jetstreams, and my dive program has a fleet of X-streams. The current versions of the two regs have the same first stage, and have for at least the last 15 years. Both have the same IP.

Servicing will be the same between both, although the xstream, for some reason only poseidon can explain, has a plastic tip on the xstream servo valve stem vs the all metal one on the Jetstream. If the purge button is pressed too hard, too many times, the servo valve will get bent in the x-stream and will need to be replaced, and it'll breathe horribly until that happens. That part is NOT included in service kits. I'm still on my original servo valve in my Jetstream from 2010.

Both breath the same as far as I could tell, there might be some differences when put on a test bench though.

X-stream is smaller, lighter and more fragile. Jetstream is a little larger, and more robust. But if you drop it, you'll crack the grating over the purge section (it'll still work fine though).

The freeflow starts at about 50-100 psi remaining pressure. Low enough that it's hard to determine what the actual pressure is based on an SPG. It probably changes depending on how much use the valve insert (the balloon) has. But you are basically out of gas, just getting some warning before you are completely SOL.

If I were choosing between the two, I would go Jetstream every time. Simply due to the stupid plastic tipped servo valve.

ETA: if you are looking at older versions, the first stages may be different and may have different IPs. Depends on the age of the reg you are looking at.

Pretty sure the “plastic” tip is meant to decrease the friction between the servo needle and diaphragm for more responsiveness over the metal one. And the IP for both is supposed to be 123 psi specifically.

 

[911964t]

 Wo

Pretty sure the “plastic” tip is meant to decrease the friction between the servo needle and diaphragm for more responsiveness over the metal one. And the IP for both is supposed to be 123 psi specifically.

Can you add a xtream to a scubapro mk11 c370 as a octo or vice versa xtream as a primary and 370 as a octo knowing that ip on xtream is 123 and c370 is 130 to 140 would that be a problem. Some like Cave Adventures Ed Sorenson in fl say it's fine you'll never notice and others say posideon has to mate together 1st and 2nd stage. As for pressure relief I've been told that c370 will act as one or if your really concerned add a pressure relief valve to a LP port. It's only the cyklon where IP is 160 that will have a problem. Does any of this make sense just want to add a xtream to a mk11 c370.