300/440/550 Js550 Pump Upgades ***NEED FEEDBACK***

Js550FTW

Js550FTW

Location
Anchor Bay, MI
Alright Guys! so i heard about the new Rhaas kit that just came out! but one tiny problem... thats out of my budget! so i came up with some ideas on increasing the size of my 550 pump for under 150 bucks give or take. so first off i want to buy a nice skat 15.5. Second I want to get a stubby pump cone. That will increase the overall volume of the pump. therefore, more water, wich should translate to more thrust right? then the obvius, bore out the nozzle for more low end jam. then this one i thought i would experiment a little on. so they make these things called pump spacers. basically how theyre supposed to work is the spacer gets installed between the jet pump vane guide case and the reduction nozzle, increasing the pressure volume between the impeller and the nozzles. This generates more thrust, as well as other benefits based on the year/model of Jet Ski it is installed on. they dont make one for a 550, so ill find some 2 inch thick alluminum and fab one up myself. i want tohear what your guys thoughts on this!

The one on the right has the spacer installed.
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bigstu

bigstu

Location
United States
Well I think diameters are much more important than lenght in this case but I would need to go back through my fluid dynamics book before I open my mouth too much. My guess it that the spacer is more for moving the nozzle further back to gain leverage over the ski for better turning.

If you do decide to do these mods it you should figure out a way to measure the thrust before mods and after mods that way you know if it made a difference.
 
Quinc

Quinc

Buy a Superjet
Location
California
Js550FTW said:
Thanks! What if I wanted better steering. Would the ski turn better. Or just spin out on me?

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Click to expand...

If you want better steering, you need to change the pivot points on the steering nozzle and steering plate.

Furter out on the steering plate, and as close to the nozzle as you can get it. Or you can buy an aftermarket quick steer plate.
 
Js550FTW

Js550FTW

Location
Anchor Bay, MI
Quinc said:
If you want better steering, you need to change the pivot points on the steering nozzle and steering plate.

Furter out on the steering plate, and as close to the nozzle as you can get it. Or you can buy an aftermarket quick steer plate.
Click to expand...
I'm gonna try to save some $$ and fab one up myself. Or I'll just bolt on an arm extension.

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