The "Hitchhiker's Guide" to the Maxi-Stream mod
- Thread starter dhnguyen
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newbie2004
New member
hello dhnguyen.
I just finished the mod last night. i did it on my MJ 1200, I follow you step by step instruction but instead of 2 prop i use 3 and the cross member is the rigid air line.
Question.
1. is the carbon shaft suppose to spin?
2. it make so much noise if it lean against the tank?
lastly HOW did you do the mount ??
thanx.
I just finished the mod last night. i did it on my MJ 1200, I follow you step by step instruction but instead of 2 prop i use 3 and the cross member is the rigid air line.
Question.
1. is the carbon shaft suppose to spin?
2. it make so much noise if it lean against the tank?
lastly HOW did you do the mount ??
thanx.
carbon shaft shouldnt really spin, it shouldnt bind to anything, be sure you put the end caps on(they should be snug and not twist around the shaft, and that you push the inner endcap into the MJ body.
you will need to push quite hard on the rod to get it into the endcap. from there the rod should be held still. there is friction on the rod to make it rotate, but not so much that it would actually twist it, or it shouldnt anyway.
it shouldnt make any noise, Im wondering if the shaft wasnt all the way in the endcap, came loose, and is now spinning and the magnet is rubbing.
you gotta get creative on the mounting, fabricate a hanger, or just glue the suction cup frame to the "top"(the side that would end up on the glass when oriented in the new direction.)
you will need to push quite hard on the rod to get it into the endcap. from there the rod should be held still. there is friction on the rod to make it rotate, but not so much that it would actually twist it, or it shouldnt anyway.
it shouldnt make any noise, Im wondering if the shaft wasnt all the way in the endcap, came loose, and is now spinning and the magnet is rubbing.
you gotta get creative on the mounting, fabricate a hanger, or just glue the suction cup frame to the "top"(the side that would end up on the glass when oriented in the new direction.)
RV8tor
New member
You what really is bad is that I went to tower hobbie to see if I could just pick some carbon fiber rod up and they cant do that. I even offer to call them and place the order and still pick it up. It ****ed me off. I have to place the order and they HAVE to ship it. I only live 40 minuetes away, but work ChamPAIGN all the time.
Shawnts106
New member
Are the Dumas 1.75 worth it? is the pitch good as Nitros??
which would you chose on the JEBO?
1.25inch? Nitro
or
1.75inch Dumas???
no doubt the 1.75 will move more water. you could go to a stainless steel prop. my gut says they must be using the top quality steel because they were no doubt designed for salt water use, and thats why they offer SS.
but some people just dont want metal in there, and I cant blame them.
its also quite expensive.
IMO on a 75g your fine with the 1.25", maybe even better, you dont want all your flow from 1 source, better if you can break it up a bit, have 2 or 3 smaller sources. 2 or 3 1.75" props might be too much
but some people just dont want metal in there, and I cant blame them.
its also quite expensive.
IMO on a 75g your fine with the 1.25", maybe even better, you dont want all your flow from 1 source, better if you can break it up a bit, have 2 or 3 smaller sources. 2 or 3 1.75" props might be too much
Brent Thomann
New member
I'm trying to build some MJ Streams for my 180 gal and keep the watts down. I read this whole post which is VERY long with tons of information ..I notice the mod has changed somewhat from "dhnguyen" first post, by the way great work!
Question is how can I get the most GPH out of my MJ900's & without it being too bulky? -what prop combo really moves the water? Was hoping I could push the water to the other end of my tank where I'd have another one or two..
1.5 pvc, dual 1.25 Nitro Hammers?
1.5" coupling, dual 1.75" Dumas props?
????
????
I search my local hobby stores for the parts first, didn't feel like ordering/waiting. Couldn't find the right props but the guy at the one hobby store pull a box out with a ton of plastic boat racing props, (I guess they call them test props). I bought quite a few of them but they were all a bit larger 2.2", 2.4", 2.9" Thought I'd eventually play around with them.
Here's a pic-
Question is how can I get the most GPH out of my MJ900's & without it being too bulky? -what prop combo really moves the water? Was hoping I could push the water to the other end of my tank where I'd have another one or two..
1.5 pvc, dual 1.25 Nitro Hammers?
1.5" coupling, dual 1.75" Dumas props?
????
????
I search my local hobby stores for the parts first, didn't feel like ordering/waiting. Couldn't find the right props but the guy at the one hobby store pull a box out with a ton of plastic boat racing props, (I guess they call them test props). I bought quite a few of them but they were all a bit larger 2.2", 2.4", 2.9" Thought I'd eventually play around with them.
Here's a pic-
Brent Thomann
New member
Will do. I need to first know what prop I should order/use on my MJ900's. Trying to push the most GPH out of them as I can. From reading this thread the prop to be used went from-
Dual 1.25" propellers by Dumas
to
1.5 pvc, dual 1.25 Nitro Hammers?
1.5" coupling, dual 1.75" Dumas props?
????
From experience please what works best?
Last edited:
ChemE
New member
If it were me, I would try progressively larger dual props until I finally got to the point that the MJ900 wouldn't turn the shaft any more and then back down a size and observe. This should consume the entire 9.5 watts which of course will produce maximum flow.
The only thing we know for sure right now is that it will take more than 2 1.75 nitros to max it out.
The only thing we know for sure right now is that it will take more than 2 1.75 nitros to max it out.
should be mentioned that if anything is to be learned from the boating industry and such, you shouldnt need 2 props. a prop is supposed to be a section of a screw and do a significant amount of what a screw could do without all the friction. so you should be able to get more flow from 1 larger prop than 2 smaller props while using the same amount of force.
of course right now we have more force, we dont have the easy means of housing a larger prop.
I suppose thats where your challenge lies, find a way to make the larger prop fit. I suppose your best bed is a series of flush bushings running from 1.5" up to probably 3.5 or 4" to fit that propellor. then perfectly center it, you should have the maximum possible flow. might be rather large and intrusive though, and that big yellow prop might be too big.
of course right now we have more force, we dont have the easy means of housing a larger prop.
I suppose thats where your challenge lies, find a way to make the larger prop fit. I suppose your best bed is a series of flush bushings running from 1.5" up to probably 3.5 or 4" to fit that propellor. then perfectly center it, you should have the maximum possible flow. might be rather large and intrusive though, and that big yellow prop might be too big.
ejmeier
Active member
I think you could house a larger prop in maybe a 1.5" to 3" bell adapter, or may even a 1.5" to 2" bell reducer too - at least for the smaller 2.25" prop - since the OD of a 2" pipe (I'm guessing) is around 2 3/8". But you might have issues mounting it because the side won't sit flush with the glass.
BTW - I'm pretty sure that the watts used will be less as the resistance increases. I can't find a reference for that to save my life though - just remember looking at some pump performance curves that included watts consumed, and the higher the pumping height (ie backpressure), the less watts consumed.
BTW - I'm pretty sure that the watts used will be less as the resistance increases. I can't find a reference for that to save my life though - just remember looking at some pump performance curves that included watts consumed, and the higher the pumping height (ie backpressure), the less watts consumed.
From my experience the larger the diameter the propellers are the more flow they will generate. Sure the picth plays some part in this but between the 1.25" Nitro with a 1.65" pitch and the 1.75" Dumas with 1.5" pitch, the larger Dumas will better choice for maximum flow. But as others have stated the challenge with the larger props will be to fashion a housing that will fit.
D.
D.
By the way I messed around last night with a MJ900 and a triple 1.25" Dumas prop design and the MJ900 had no problems whatsoever turning. Adding a third propeller it seems will generate even more flow. The drawback is that there is more vibration and noise when comparing against the 2 prop design or the 1 prop design (quietest)
D.
D.
The only thing I had to do was sanded down the OD just a little so that the pipe will fit through but you would have to do that with the regular 1.5" SCH40 PVC pipe as well as the 1.5" VC test cap. Once the rubber gasket ring was removed form the MJ body, the ID is a perfect fit though.
D.
D.
as I said, in the old days they used a screw, like the kind of thing you'd see on a hole digger or a drill. then somewhere along the line they cut it down to a segment. of course some efficiency is lost, but I have to assume they use props and not screws for a reason. I used 2 props, yes its more flow than 1, yes 3 is probably more than 2, and 4 is probably more than 3. but Im willing to bet a 1.75" prop is better then all of them.
and if you could take enough 1.25" props to equal the flow of 1 1.75" prop, Im also betting that the 1.75" prop would be easier to turn.
1 important point is that we are using multiple props, and each prop has its own leading edge where there is alot of its resistance, if it was a true continuous screw than it would just be the friction of the water on the additional surface area. but we dont have that available to us unfortunatly.
and if you could take enough 1.25" props to equal the flow of 1 1.75" prop, Im also betting that the 1.75" prop would be easier to turn.
1 important point is that we are using multiple props, and each prop has its own leading edge where there is alot of its resistance, if it was a true continuous screw than it would just be the friction of the water on the additional surface area. but we dont have that available to us unfortunatly.
Brent Thomann
New member
I actually went to Lowes last night after I picked up the large props and found some type of gray bushing/coupler (in electrical) looking thing that I be able to create a housing from pretty easy.
I wanted to first build a unit with the recommended props from this thread and then I was going to experiment with the larger props to compare later. I'd post pic's as well.
My 900 was able to turn the big yellow prop (about 3") outside of the water but was unable to turn it once it was in the water. Maybe it would work with the 1200? The smaller props I have (2.2 & 2.4) worked under water with the mj900. I didn't do any gluing just temporary slid the props onto where the original prop was on the MJ, after a couple seconds it would slid off. It did seem to push the water pretty good though while it was on. Not sure how good cause I don't have anything to compare it too. I'll order some 1.25 nitros and some 1.75 dumas from tower.
Shawnts106
New member
Thanks for the INFO, I think Ill do duel 1.75Dumas props with the jebo pump for my 210!!!...
but I do want to try a MJ... 1200's is all I have, but may be able to fine a 900 somewhere...
isnt it the Nitros 1.25inch that you use for the MJS?
but I do want to try a MJ... 1200's is all I have, but may be able to fine a 900 somewhere...
isnt it the Nitros 1.25inch that you use for the MJS?
ejmeier
Active member
I wonder if those little rubber caps that fit on the ends of the shaft have anything to do with this? Do you think they just put them on there to keep the impeller/magnet from coming off the shaft when disassembling, or do you think they have more of a cushioning effect for vibrations? Seems like if you had those little nobs on each end of the shaft, it might help absorb some of the rattling rather than pass it on to the housing.
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