How much does thr maxijet mod increase the flow?
- Thread starter Razzagas
- Start date
shelburn61
New member
You talking about the stream mod or melev's mod?
A 1200 stream is capable of putting out 1000-2000 gph depending on propeller. Another huge benefit is the wider flow stream.
A 1200 stream is capable of putting out 1000-2000 gph depending on propeller. Another huge benefit is the wider flow stream.
shelburn61
New member
you are wrong 
replacing the impeller with an RC boat propeller makes a huge differnce
replacing the impeller with an RC boat propeller makes a huge differnce
ChemE
New member
The flow depends very little on the powehead used but rather on the propeller it is turning. The MJ1200 spinning the 1.75" Dumas prop is putting out somewhere in the neighborhood of 3,000 gph. The 400 spinning dual 1.25" Nitro Hammers (depreciated now due to inferior performance vs. the Octura props) puts out around 1,000 gph. Everything else is somewhere in between.
A 600 spinning an aggressively pitched 1.25" prop is all the flow my 55 gallon tank can tolerate.
yardboy
Advanced Bewilderment
While I don't doubt that the flow is GREATLY increased with the mod, where or how can you calculate or measur how much flow it is putting out?
I have a duel 1.75" prop on a MJ 1200 directed across the front of a 5' 150 and it not only goes all the way across the tank, but every polyp in there is feeling the effects. If I direct the flow even slightly downward, it digs up all the sand in the corner of the tank. Unbelievable.
I have a duel 1.75" prop on a MJ 1200 directed across the front of a 5' 150 and it not only goes all the way across the tank, but every polyp in there is feeling the effects. If I direct the flow even slightly downward, it digs up all the sand in the corner of the tank. Unbelievable.
ChemE
New member
Hold an empty plastic bag of known volume underwater so that it gets 100% of the flow the mod puts out. Start the mod, and note how long it takes to fill the bag. This is how it is done by Tunze, and how the mods have been tested. Very few have been tested because no one really cares to know what the absolute number is. We have a pretty good feel for how much is enough and how much is too much based on tank size and propeller size. Do some testing and share some numbers.
Indeed that sounds incredible. My results are disappointing.
I modded a MJ900 with an Octura 1435 after hearing that the 1.75 dumas would blow the back wall off my 65. Well, I can barely feel the flow accross the 20H sump that I am testing with. It is quiet though and starts every time which is cool, and I can get some cool vortex action if I raise it up near the waterline, there just isn't a lot coming out the front of this thing like I keep reading about.
The CF rod doesn't fit inside the 316 thinwall that I got at the LFS, so I had to scrounge a bunch of plastic pens and pencils until I found something that worked, and I hope to rig up either a single or double 1440 this weekend for comparison. The pictures in my gallery are from when I had the dumas on it, but I had numerous problems related to trying to drill out the thinwall tubing and it all being off kilter.
jp
ChemE
New member
JP,
Sorry to hear the mod hasn't worked for you. I put a 1.25" prop on a MJ600 and the flow is insane in my 55. One thing I noticed during my experimentation that might make all the difference for you is prop placement within the shroud. The further back the prop is in the shroud the less flow is produced. For me, cutting the shroud back 1cm made a huge difference. Perhaps this is your problem?
Sorry to hear the mod hasn't worked for you. I put a 1.25" prop on a MJ600 and the flow is insane in my 55. One thing I noticed during my experimentation that might make all the difference for you is prop placement within the shroud. The further back the prop is in the shroud the less flow is produced. For me, cutting the shroud back 1cm made a huge difference. Perhaps this is your problem?
OK, here's what I got:
When assembled, the prop spins right about where the middle zip tie is. This is the same shroud as is in my gallery, just with some gutter guard wrapped around.
It would be awesome to hear that I have the prop on backwards, but I will try hacking about an inch off the back and test again. The prop spins very freely, since this is the bushing to be used for the 1.75" dumas.
jp
When assembled, the prop spins right about where the middle zip tie is. This is the same shroud as is in my gallery, just with some gutter guard wrapped around.
It would be awesome to hear that I have the prop on backwards, but I will try hacking about an inch off the back and test again. The prop spins very freely, since this is the bushing to be used for the 1.75" dumas.
jp
zapata41
In Memoriam
i think you need to trim your shroud down some. i have my props every close to the end of the shroud and run a very short shroud. i leave just enough room for the prop to spin the right way and not hit the stopper.
also to the guy running dual 1.75 dumas props on the mj1200, drop one ofthe props, you'll get way better flow from a single duams vs. the dual.
Tim
also to the guy running dual 1.75 dumas props on the mj1200, drop one ofthe props, you'll get way better flow from a single duams vs. the dual.
Tim
