I'm looking for a jet drive for a small boat project that I'm not sure exists. Plenty of jets out there for 500cc and up (jetski/waverunner type), and at least one or two for motorized kayaks in the 5-6 hp range. I'm thinking more like 150cc/10-15 hp range.
Anyone help me learn stuff? I need to know the basics of how to choose an impeller/housing combo for my 10-15hp plans, then be able to scavenge one to graft into my boat.
If everything else fails, they're basically the pressure side of a turbo, right? Should be able to graft one of those on there.
The thought had crossed my mind. I'm not sure how the difference between fluid and air would affect the efficiency. Part of the goal here is light weight, which means smaller engine/high efficiency. Well, as high efficiency as any hydro jet can ever be, that is.
I kinda need to do it "right" in the GRM sense, but I lack the knowledge required to just start grabbing parts. I have a feeling that jets are just like turbos. They work within a certain range of displacements and efficiency/surge, so I would hate to get a random pump and be disappointed after I spend all that time grafting it in.
Depending on how in to it you want to get, you could "bench" test it fairly easily with a decent sized tub of water. Anything black would be rigid, the grey would be the spinning shaft, the snail is... you know what it is.
Mr_Asa said:If everything else fails, they're basically the pressure side of a turbo, right? Should be able to graft one of those on there.
To be precise, they're more like the outlet of a Roots style blower. Fluids + centrifugal compressor = lots of waste to spinny things and direction changes. Water jets are typically axial, more like a jet engine on a plane.
Kawasaki jetski specs.
1973-1976 JS400 24.5 HP
1977-1992 JS440 27HP
1982-1985 JS550 36HP
1986-1990 JS550 41HP
1991-1995 JS550SX 47HP
1986-1988 JS300 & 1987-1991 300SX 30HP ALL MODELS
This site has some in the 25hp range. Might be smaller that I didn't see.
http://outboardjets.com/outboard-jets-product-catalog/small-series/
20-35HP range here, should be adaptable to smaller considering its OMC
Ooo... seems like exactly what you want to do.
Can't do an outboard. The centrifugal pumps are very inefficient, and the whole kit and caboodle would most definitely sink the back. I can get a free 15 hp that weighs 30 lbs in the form of a GY6, or the outboard with the jet unit is more like 150+ lbs for 20hp. The bottom line is that getting enough power out of an outboard jet is A) super expensive, and B) not a hp/weight ratio that is favorable in this application. That is to say, I can't get the power I want in a weight that won't risk taking on water. This thing is the size of a sheet of plywood, after all.
As it is, the 3.5hp only weighs something like 46 lbs, and hanging off the transom with my 225-lb butt in it might be too much.
The Jettender is a fun looking thing. I'll see if I can find anything about their jet pumps
No outboard? I may have missed something as I thought you wanted to adapt a jet drive to an outboard that never had one.
No... I want to cut a hole in the bottom and put a jet dive in much like a jet ski
Outboards are the kings of power/weight in most cases until you get smaller. Add to the fact that centrifugal jets on outboards aren't very efficient, the power/weight ratio isn't really a thing anymore.
I could install a whole Jet Ski center section like Toyman did, but the smallest one I've found is 500cc, too much power, and too heavy for this tiny boat.
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