CAvitation with bored nozzle wet wlf cone combo?

MADMAT

MADMAT

Location
Ohio
I saw someone mention it. I'm running 13/16 cutback with worx intake and blowsion cone right now but I have a bored nozzle coming from Paul. Is it just to much?
 
Yamah0

Yamah0

XFT
Location
Dubai
Im running a 12-17 skat trak with a wet wolf cone and 85mm bored nozzle.... I think you dont want to bore the nozzle more than 85mm, otherwise ull have a better chance cavitating.
Im about to put in a concord 13-15 cutbak.. so we'll see. I think it'll still be fine.

Zane...
 
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SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
I've heard of a few people getting cavitation at 85.5mm with a cone, but with the stock cone they were fine.
 
SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
I've got a 13/15 (or 16, not don't remember), 85mm nozzle, with Wet Wolf cone and I'm fine. But then again, my ski has zero hp right now. heh

More hp will lead you to cavitation too.
 
C

cybermob2

naturally warming water
i'm running 13/15 cutback with cone and 85mm nozzle. no cavitation except RIGHT out of the hole at less than 5mph. running limited setup with bpipe and head.

i keep forgetting to swap out the cones and nozzles for stock and check the difference.
 
Crab

Crab

thanks darin...noswad!
Location
Seattle
This whole concept of cavitation from too much nozzle or not enough internal pump pressure baffles me. My boat ran great for top end with the stock nozzle size, but when I put on the large bore Ocean Pro setup it cavitates bad until the boat gets going. Too big?
 
Crab

Crab

thanks darin...noswad!
Location
Seattle
steve802cc said:
Yes too big a nozzle will do that.
STeve
Click to expand...


Anyone know why that is, or the physics behind it? The only thing I can figure is that it has something to do with lack of pressure in the pump as the engine revs up, inducing cavitation on the low pressure side of the impeller. Water just can't get into the pump fast enough to keep it full (standing still), so the water separates into vapor inducing cavitation. I read the vapor part somewhere.
 
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SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
[SIZE=-1]Basically, cavitation means you are decreasing the pressure like right behind the blade (and can happen behind a broken stator vane) to the point where the water "boils". Since water is not compressible, you can't "stretch" it either.

There are 2 ways to prevent this, either have enough backpressure from the nozzle, or feed enough water to the pump. Not feeding enough is just like if you clog your intake grate with something, the pump can't get enough water so it cavitates. The other situation is having too large of a nozzle.

There is a lot more too it, but that's the main stuff.

(was on a submarine, propellor cavitation is bad because it makes noise as the bubbles collapse)

The production of voids in a liquid system due to extreme reduction of internal pressure. Collapse of these voids or cavities produces very large impulsive pressure, which can cause considerable damage to nearby surfaces. Cavitation is frequent on high speed propeller blades
Click to expand...
[/SIZE]
 
Crab

Crab

thanks darin...noswad!
Location
Seattle
That must be why the SXR pump trick is to convert it to a large hub to increase internal pump pressure and thrust. All the power in the world is usless if you can't convert it to usable thrust.
 
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