SoCal Jet Boats
Tech Talk => Fabrication => Topic started by: 69kona on December 17, 2016, 09:29:13 PM
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Hey guys I got the O.D machined and the inside cut to the size I want. That's as far a my lathe skills go lol . Any input on machining a taper ? Without a taper attachment ..
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How long of a taper? Looks like the compound should handle it. If you can't cut it all in one pass, you cut as far as you can. Then reposition the carriage to make a second cut and blend the two.
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Ok I guess I try that Thanks Flusher . It a 2 inch long taper .
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The compound should handle 2" no problem.
Is that a velocity stack?
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Nozzle insert ..
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Worked great thanks for the tip Flusher 👍🏻
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Sweet!
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Whoa... how small you choking that nozzle down to?
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Whoa... how small you choking that nozzle down to?
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3.095..
I had a 3.250
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Too small ?
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3.095..
I had a 3.250
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What's your thoughts on the smaller insert?
Unless your boat is silly, Pringle potato chip light, you may have crossed a line.
GT
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3.00" is the smallest they even make.
I have a feeling the sweet spot is 3.125"- 3.25".
JMO
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Oh... 3.095 is not what I was expecting you to say... it just looks crazy small for some reason with how thick it is. Must be the photo... my eyes... or whatever. That is actually not too far out of the realm of normal... lot of gullwings like the 3.060-3.090 range.
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Oh... 3.095 is not what I was expecting you to say... it just looks crazy small for some reason with how thick it is. Must be the photo... my eyes... or whatever. That is actually not too far out of the realm of normal... lot of gullwings like the 3.060-3.090 range.
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It's for a 16-6 ft deeper v hull guessing 600lb +or- . Do u think I'm in the ball park for size?
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Guessing on weight lol
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Do u think I'm in the ball park for size?
The good thing is, you now have options.
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The good thing is, you now have options.
Would u say by going down in nozzle size, I'm gonna see higher suction pressure ?
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What's your thoughts on the smaller insert?
Unless your boat is silly, Pringle potato chip light, you may have crossed a line.
GT
I'm thinking I'll gain alittle more top end .
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I'm thinking I'll gain alittle more top end .
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Lot easier to change props
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I'm thinking I'll gain alittle more top end .
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RPM or MPH?
Or both?
My guess would be a loss of out of the hole with a barely measurable speed gain. Potentially a small loss in RPM depending of power curve.
GT
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RPM or MPH?
Or both?
My guess would be a loss of out of the hole with a barely measurable speed gain. Potentially a small loss in RPM depending of power curve.
GT
Won't a bigger nozzle top out in speedwise faster than a smaller nozzle?
My thinking was buy running a smaller nozzle it may help my pumps slight cavitation problem out of hole. Just me thinking here lol ...that it would desire less water .. Possibly bigger nozzle more water demand ?
In any case the pump is tight and it has a inducer .
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My thinking was buy running a smaller nozzle it may help my pumps slight cavitation problem out of hole.
Indeed.
Increasing bowl pressure and therefore the pressure on the back side of the impeller by restricting the pump discharge (nozzle) will reduce cavitation.
Increasing nozzle size does not increase the pump's demand for water. If the engine and impeller combination are able to push more water, a larger nozzle will allow the entire system to process more water.
Another thing to look at is the intake opening, biting edge, et al. Configuring pump hardware is a balancing act represented by (P1 * V1) = (P2 * V2) where P = pressure and V = volume. Think of the impeller as the "=".
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Indeed.
Increasing bowl pressure and therefore the pressure on the back side of the impeller by restricting the pump discharge (nozzle) will reduce cavitation.
Increasing nozzle size does not increase the pump's demand for water. If the engine and impeller combination are able to push more water, a larger nozzle will allow the entire system to process more water.
Another thing to look at is the intake opening, biting edge, et al. Configuring pump hardware is a balancing act represented by (P1 * V1) = (P2 * V2) where P = pressure and V = volume. Think of the impeller as the "=".
Thanks for info ! This makes me think ...
Does it comes down to horsepower and boat weight to help determine nozzle size?
I have a new motor that I put in this winter that has quit a bit more horsepower than the one mill .
I want to get the pump hardware dialed in ...
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Thanks for info ! This makes me think ...
Does it comes down to horsepower and boat weight to help determine nozzle size?
I have a new motor that I put in this winter that has quit a bit more horsepower than the one mill .
I want to get the pump hardware dialed in ...
What impeller? Is it turning at the peak horsepower RPM? Particularly the front side of the impeller is prone to cavitation. I would start there.
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What impeller? Is it turning at the peak horsepower RPM? Particularly the front side of the impeller is prone to cavitation. I would start there.
A impeller... with old motor I was spinning 5600rpm on the bottle and 5100rpm all motor
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Aluminum Berkeley?
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Aluminum Berkeley?
Yeah .
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The leading edges of the impeller vanes need to be sharp. Those impellers also have huge fillet radii that extend out into the hub and shroud.
I bet you will see some cavitation burn in these areas.
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The leading edges of the impeller vanes need to be sharp. Those impellers also have huge fillet radii that extend out into the hub and shroud.
I bet you will see some cavitation burn in these areas.
Detail my impeller?
change impeller to a Legend or a aggressor ?
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I was thinking more doing a tuneup on your impeller. Detailing is a more involved process. I don't think you are ready to upgrade to a stainless.
Just understand that a proper front detail will take RPM out of the engine.
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I was thinking more doing a tuneup on your impeller. Detailing is a more involved process. I don't think you are ready to upgrade to a stainless.
Just understand that a proper front detail will take RPM out of the engine.
If I pull my impeller ..do u have time to tuneup my impeller ? I'm not worried about loss in some rpm.
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Aluminum impellers are pretty soft and nick pretty easy. Every little imperfection contributes to cavitation and reduced performance (picture 1 & 2).
You can tuneup minor damage with a file. Start filing with the file vertical (picture 3) to remove all the dings. Once you get all of the dings straightened out, file to the bottom of the vanes (picture 4) to sharpen the leading edges. You want them pretty sharp. I break the edge only enough so that it doesn't cut me.
This example is to the point where I would hit it with a sanding roll in a die grinder. You really don't want to remove material from the front surface of the vanes. It's important to not change the angle of attack.
Tuning your impeller won't cause it to lose RPM unless it has severe damage.
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A front detail is quite a bit more involved. The vanes are thinned, recontoured, and sharpened to bite harder and so each vane bites the same. The hub is machined to blend smoothly with the shaft. There is quite a bit of hand grinding and polishing after machining.
A properly front side detailed impeller will bite and launch a lot harder, about equivalent to a stock impeller that is one full cut size larger.
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A front detail is quite a bit more involved. The vanes are thinned, recontoured, and sharpened to bite harder and so each vane bites the same. The hub is machined to blend smoothly with the shaft. There is quite a bit of hand grinding and polishing after machining.
A properly front side detailed impeller will bite and launch a lot harder, about equivalent to a stock impeller that is one full cut size larger.
Hey bud was taking to u the other day about tuning up my impeller. Well I started and this thing has some deep casting marks but i got a little done. Just seeing if I'm going the right way lol
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The polishing makes zero difference, don't waste your time.
The nicks and dings on the leading edges are what you want to "tune" out.
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Thanks bud ..I've worked on it alittle more today. I'm wondering about the pits in the casting ?
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