SoCal Jet Boats
Tech Talk => Jet Pumps => Topic started by: steves86ta on July 18, 2016, 01:40:11 PM
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Can someone smarter than I am explain this to me?
I took quite a few GPS readings with my boat over the weekend. I never really checked out the cruise speed and stuff like that so i wanted to.
Heres what i learned with my Stock Berkeley C impeller
At a cruise of around 3500 rpm i am in the neighborhood of 35-37mph.
At 4k rpm i am right about 40-43mph.
At a WOT rpm of 4900 on 91 (higher on the race fuel for some reason) i saw 70 mph. On race fuel, i saw a max rpm of 5200 and a mph of 72.6 mph.
Heres what i dont understand....
Why is that last 1-1200 rpm worth damn near 30 mph? Is this because the pressures go up that much higher in that last 1000 rpm?
Im guessing my boat weighs in the 900-1200 pound range without running gear.
I rode in my friends boat, its a 19 Spectra. He has an AB impeller.
Without moving his diverter, it felt to launch harder. According to his tach he spins about 4800 RPM. On GPS he is at 50mph exactly.
The way i understand jets, are the bigger the impeller, the more thrust with more rpm. I would expect his boat to be atleast closer to the speed i am with the sameish rpm and a bigger impeller.
GT, Flusher? Someone smarter than i am that can educate me on this? I dont think his boat weighs to much more than mine, it feels lighter moving it around on the beach
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The answer is going to piss you off.
All the lower numbers are very low hp. It's not until you get near WOT that any horsepower is being generated.
Your not spinning a prop that has a pretty good bite on the water, you are squirting water at high pressure to create thrust. You could hold your boat back with a fairly small rope. Whereas the prop boat can't be held back as easily.
The thrust required to get the hull freed up from the drag of the water is on the higher horsepower, it has zero to do with actual rpm.
Your understanding of impeller cut is 100% backward, the C cut impeller is much smaller than an A. You can cut an A to a C, but not the other way around.
The more impeller, the more HP it takes to spin.
The reason an impeller is "cut down" is to get the engine the ability to turn it's optimum rpm to get the most hp out of it.
In short, rpm is not speed, hydrodynamic drag, nozzle volume and velocity determine the speed.
And that Spectra bottom is like the cute chubby chick at the bar, built for comfort, not speed. Lol
GT
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Good question and good answer from the both of yuhs.
So in short, I drop a B or C in from the A I have now I then go faster?
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The answer is going to piss you off.
All the lower numbers ate very low hp. It's not until you get near WOT that any horsepower is being generated.
Your not spinning a prop that has a pretty good bite on the water, you are squirting water at high pressure to create thrust. You could hold your boat back with a fairly small rope. Whereas the prop boat can't be held back as easily.
The thrust required to get the hull freed up from the drag of the water is on the higher horsepower, it has zero to do with actual rpm.
Your understanding of impeller cut is 100% backward, the C cut impeller is much smaller than an A. You can cut an A to a C, but not the other way around.
The more impeller, the more HP it takes to spin.
The reason an impeller is "cut down" is to get the engine the ability to turn it's optimum rpm to get the most hp out of it.
In short, rpm is not speed, hydrodynamic drag, nozzle volume and velocity determine the speed.
And that Spectra bottom is like the cute chubby chick at the bar, built for comfort, not speed. Lol
GT
Maybe i explained incorrectly. That is exactly how i understood the cuts. Basically i understood it as an AB impeller moving more water than a C impeller at the same RPM.
So if i understand correctly. Even though the top RPM is about the same, and he is running a "bigger" impeller i am creating more thrust?
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So in short, I drop a B or C in from the A I have now I then go faster?
Nope, probably make more noise and break more parts.
JMO
GT
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Good question and good answer from the both of yuhs.
So in short, I drop a B or C in from the A I have now I then go faster?
The way i understand it, and GT please correct me if i am wrong.
You could go to a B or C and gain some top end RPM. But you are moving less water so you may or may not go any faster.
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Nope, probably make more noise and break more parts.
JMO
GT
Damn it! My reading comprehension sucks.
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The way i understand it, and GT please correct me if i am wrong.
You could go to a B or C and gain some top end RPM. But you are moving less water so you may or may not go any faster.
Correct, RPM is not speed unless you are significantly increasing the amount of horsepower developed.
GT
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Correct, RPM is not speed unless you are significantly increasing the amount of horsepower developed.
GT
Okay, so thats what i dont understand! Maybe im stupid
But my friend has a mostly stock 460 with an AB impeller. (larger than my C) and he is spinning 4800 rpm but is considerably slower than i am.
OR... and i just thought about this!
Maybe, because hes just running a stock rock grate maybe his pump is loading as hard as mine is with the loader. Hence letting it run more rpm than it really should?
OR
Maybe his tach isnt accurate
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Maybe i explained incorrectly. That is exactly how i understood the cuts. Basically i understood it as an AB impeller moving more water than a C impeller at the same RPM.
So if i understand correctly. Even though the top RPM is about the same, and he is running a "bigger" impeller i am creating more thrust?
I would say absorbing more power, which could mean the same thing.
You can't get something for nothing, so I always need to keep the verbiage plain.
Bottom design, weight distribution and horsepower likely had more to do with the dramatic difference in to speed.
GT
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I would say absorbing more power, which could mean the same thing.
You can't get something for nothing, so I always need to keep the verbiage plain.
Bottom design, weight distribution and horsepower likely had more to do with the dramatic difference in to speed.
GT
Okay! Last question and then i promise im dropping it. I learned a lot
Im spraying pretty good out of my pivot holes for my reverse bucket (reverse cable broke) How bad is this effecting the nozzle pressure? I would htink it would have the effect of going to about an inch larger nozzle since the pins are what half inch or so?
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv643%2Fsteves86ta%2FMobile%2520Uploads%2FIMG_20160717_152353_zpsnu4ax19p.jpg&hash=d9d6345ef9e1b08987c05b2c998436be41bfcb6b) (http://smg.photobucket.com/user/steves86ta/media/Mobile%20Uploads/IMG_20160717_152353_zpsnu4ax19p.jpg.html)
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Okay! Last question and then i promise im dropping it. I learned a lot
Im spraying pretty good out of my pivot holes for my reverse bucket (reverse cable broke) How bad is this effecting the nozzle pressure? I would htink it would have the effect of going to about an inch larger nozzle since the pins are what half inch or so?
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv643%2Fsteves86ta%2FMobile%2520Uploads%2FIMG_20160717_152353_zpsnu4ax19p.jpg&hash=d9d6345ef9e1b08987c05b2c998436be41bfcb6b) (http://smg.photobucket.com/user/steves86ta/media/Mobile%20Uploads/IMG_20160717_152353_zpsnu4ax19p.jpg.html)
Probably no where near as bad as you think.
Might make a 1 or 2% difference. Maybe.
Those holes are perpendicular to the flow of water and are only 3/4".
This is exactly why wine corks are the size they are.
Lmao
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Probably no where near as bad as you think.
Might make a 1 or 2% difference. Maybe.
Those holes are perpendicular to the flow of water and are only 3/4".
This is exactly why wine corks are the size they are.
Lmao
lmao i didnt even think about that. Oh well made for a funny looking video.
Thank you for your information, this is why we come here. And the answer nowhere near pissed me off lol
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lmao i didnt even think about that. Oh well made for a funny looking video.
Thank you for your information, this is why we come here. And the answer nowhere near pissed me off lol
I was thinking piss you off in a face-palm sort of way.
Lol
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I was thinking piss you off in a face-palm sort of way.
Lol
Now if you could figure out why this C impeller actually launches, vs the American Turbine B- i had that would cavitate like a mofo that would be great.
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Now if you could figure out why this C impeller actually launches, vs the American Turbine B- i had that would cavitate like a mofo that would be great.
Maybe wear ring clearance.
Just a WAG.
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Maybe wear ring clearance.
Just a WAG.
The AT measured at .012 on each side if i remember correctly. Std wear ring, and its also a brand new impeller.
Front/rear clearance was machined down to be .030"
Even added a stuffer with .030" clearance and still cavitated like a mofo
Put the box stock berkeley in, took the stuffer out (wouldnt fit) and it works great
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measured 7.225
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heres the wear ring im running
http://www.cpperformance.com/p-489-standard-size-stainless-steel-wear-ring.aspx (http://www.cpperformance.com/p-489-standard-size-stainless-steel-wear-ring.aspx)
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Ok, swap out the aluminum A for a stainless A(and whatever else would need to be changed to make it work) does that improve performance? Better handles the FORD power?
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The AT measured at .012 on each side if i remember correctly. Std wear ring, and its also a brand new impeller.
Front/rear clearance was machined down to be .030"
Even added a stuffer with .030" clearance and still cavitated like a mofo
Put the box stock berkeley in, took the stuffer out (wouldnt fit) and it works great
The nose on that impeller is an obstruction causing gigantic amounts of aeration in the eye over the impeller, blows a huge hole in the water.
Notice the thickness at the shaft shoulder? Never work.
The Berkeley impeller likely has a shoulder the same as the shaft.
Mystery solved.
GT
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Ok, swap out the aluminum A for a stainless A(and whatever else would need to be changed to make it work) does that improve performance? Better handles the FORD power?
I dont think cut for cut youll see a difference. Now if you get with someone like B1 or MPD and have the stainless detailed you might notice a difference.
I really need to look into getting something stronger
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Ok, swap out the aluminum A for a stainless A(and whatever else would need to be changed to make it work) does that improve performance? Better handles the FORD power?
The performance difference between the two would be negligible.
The stainless would just be able to do it longer. Lol
GT
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The nose on that impeller is an obstruction causing gigantic amounts of aeration in the eye over the impeller, blows a huge hole in the water.
Notice the thickness at the shaft shoulder? Never work.
The Berkeley impeller likely has a shoulder the same as the shaft.
Mystery solved.
GT
So is this impeller trashed? Or can I detail and cleaned up to improve the flow?
For what its worth
I had the same problem before we cut it down to tighten the clearances up. And tightening it up did improve it.
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The AT measured at .012 on each side if i remember correctly. Std wear ring, and its also a brand new impeller.
Front/rear clearance was machined down to be .030"
Even added a stuffer with .030" clearance and still cavitated like a mofo
Put the box stock berkeley in, took the stuffer out (wouldnt fit) and it works great
Your American turbine B impeller cavitated before you tighten up the the clearances and added a stuffer ...
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Your American turbine B impeller cavitated before you tighten up the the clearances and added a stuffer ...
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yeah like i said "For what its worth I had the same problem before we cut it down to tighten the clearances up. And tightening it up did improve it."
But maybe, even stock it was pretty obtrusive there
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So is this impeller trashed? Or can I detail and cleaned up to improve the flow?
For what its worth
I had the same problem before we cut it down to tighten the clearances up. And tightening it up did improve it.
You could either detail it out to smooth the shaft transition or cut the shaft for an inducer.
Where the hell is Joe?
GT
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The nose on that impeller is an obstruction causing gigantic amounts of aeration in the eye over the impeller, blows a huge hole in the water.
Notice the thickness at the shaft shoulder? Never work.
The Berkeley impeller likely has a shoulder the same as the shaft.
Mystery solved.
GT
Mystery not solved it cavitated before the impeller was cut.... Just saying
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Mystery not solved it cavitated before the impeller was cut.... Just saying
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yeah that is true. It was cavitating worse before we cut it down.
But now im wondering if from the factory the AT is a thicker shoulder there and thats why it cavitated when it was new and after.
Maybe ill get down and dirty with my dremel and clean this up and try it again to see what happens.
OR just finally add an inducer
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Mystery not solved it cavitated before the impeller was cut.... Just saying
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What was cut? The thrust face or the wear ring face?
GT
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What was cut? The thrust face or the wear ring face?
GT
If thrust face is the area that you are talking about, Yes that was cut down.
We also cut down the back side of the impeller so we could bring the clearances to .030
heres a picture where we cut, both faces where there is blue
If i remember correctly my front clearances were massive before we cut it. Somewhere around .125 and .140 between the front of the impeller, and the "back" where the .140 is in the picture
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these clearances were from the impeller to the suction housing.
We cut both sides enough to bring the clearance to .030 on both surfaces
BUT i had the cavitation worse before we did this. Figured the excessive clearance was why it was cavitating so badly.
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If thrust face is the area that you are talking about, Yes that was cut down.
We also cut down the back side of the impeller so we could bring the clearances to .030
heres a picture where we cut, both faces where there is blue
If i remember correctly my front clearances were massive before we cut it. Somewhere around .125 and .140 between the front of the impeller, and the "back" where the .140 is in the picture
Should have left it alone and used a shouldered ring.
JMHO, never cut the thrust face.
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Now, if i do buy an inducer, is it recommended to try to blend them together the best i can?
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Should have left it alone and used a shouldered ring.
JMHO, never cut the thrust face.
Right ... Steve told me to do it ..🤗🤗 lol I cut the shaft shoulder on them
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Right ... Steve told me to do it ..🤗🤗 lol I cut the shaft shoulder on them
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Hey now! When we talked about it we both agreed to do it!
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Hey now! When we talked about it we both agreed to do it!
Lol
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Lol
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and answer your damn phone!
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Dumb question.... What makes a stainless impeller so much better than aluminum? Wear factor? I wouldn't think they deflect like a stern drive prop... I'm new too so just humor me 😁
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Dumb question.... What makes a stainless impeller so much better than aluminum? Wear factor? I wouldn't think they deflect like a stern drive prop... I'm new too so just humor me 😁
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Strength. I guess aluminum don't like to stick together at high rpm. Also if you shock load the pump it's hard on an aluminum one
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Dumb question.... What makes a stainless impeller so much better than aluminum? Wear factor? I wouldn't think they deflect like a stern drive prop... I'm new too so just humor me 😁
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The aluminum impellers can't handle HP above ~500 or so. They crack and break.
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Dumb question.... What makes a stainless impeller so much better than aluminum? Wear factor? I wouldn't think they deflect like a stern drive prop... I'm new too so just humor me 😁
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An aluminum deflects and distorts in a major way. A stainless holds its shape much better and is not prone to the cavitation burn aluminum impellers are susceptible to.
GT
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The aluminum impellers can't handle HP above ~500 or so. They crack and break.
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Like this lol (about 600hp on the bottle)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv643%2Fsteves86ta%2F20160115_145426_zps3ipelxrj.jpg&hash=69557dde6d8cbda3d7858f65a9ff19b725ff7abb) (http://smg.photobucket.com/user/steves86ta/media/20160115_145426_zps3ipelxrj.jpg.html)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv643%2Fsteves86ta%2F20160115_145435_zpsma4satlk.jpg&hash=388e71805f17c84ebdd6841d140138df8efd3368) (http://smg.photobucket.com/user/steves86ta/media/20160115_145435_zpsma4satlk.jpg.html)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv643%2Fsteves86ta%2F20160113_170900_zpsbsnztuad.jpg&hash=6a5d43d64883f3cf551cfec04fa1747a109b3efe) (http://smg.photobucket.com/user/steves86ta/media/20160113_170900_zpsbsnztuad.jpg.html)
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv643%2Fsteves86ta%2F20160115_145445_zpsgjfnxy6l.jpg&hash=a292dbd98ee502d5a84ebb08493464fccf7e91e5) (http://smg.photobucket.com/user/steves86ta/media/20160115_145445_zpsgjfnxy6l.jpg.html)
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The aluminum impellers can't handle HP above ~500 or so. They crack and break.
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Exactly!!! Workin on breaking mine. Ya!!!
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So a stainless one is a waste of money if I'm only pushing 350-400 hp?
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So a stainless one is a waste of money if I'm only pushing 350-400 hp?
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Do you suck up rocks and other shit often?
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No rocks yet! But I've only had the boat a couple months. Been working some bugs out of it. Using it on one of the local lakes so nothing real shallow. Probably head to the river in the next week or two.
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No rocks yet! But I've only had the boat a couple months. Been working some bugs out of it. Using it on one of the local lakes so nothing real shallow. Probably head to the river in the next week or two.
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IMO I wouldn't spend the money
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IMO I wouldn't spend the money
Kind of what I figured. Still getting used to all this stuff. Lot of info flying around on here! LOL
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So a stainless one is a waste of money if I'm only pushing 350-400 hp?
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All depends on where that hp comes from, if it's at 8,000rpm, then you need a stainless. Under 5,500, you're good.
GT
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So a stainless one is a waste of money if I'm only pushing 350-400 hp?
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All depends on where that hp comes from, if it's at 8,000rpm, then you need a stainless. Under 5,500, you're good.
GT
So it's more of an rpm issue and rotating mass? I was told by the guy I bought the boat from that the pump had work done to it. He didn't know exactly what though. How can you tell without pulling the pump apart what is in it? (As far as aluminum or stainless)
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So it's more of an rpm issue and rotating mass? I was told by the guy I bought the boat from that the pump had work done to it. He didn't know exactly what though. How can you tell without pulling the pump apart what is in it? (As far as aluminum or stainless)
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Both, I would not spin an aluminum past about 5,500 RPM or put more than 500 HP through it (which can be done at less than 5K)...
GT
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Both, I would not spin an aluminum past about 5,500 RPM or put more than 500 HP through it (which can be done at less than 5K)...
GT
So I'm on thin ice when on the bottle then
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So I'm on thin ice when on the bottle then
X2 on pure NA in my Ford.
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X2 on pure NA in my Ford.
Impeller will last longer than the Ford 😁
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Impeller will last longer than the Ford 😁
Lol. Very possible.
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Lol. Very possible.
Seriously though. I've been told by a couple people that put some serious HP to their aluminum impellers they can last
Just depends on how you treat it. Mainly keeping the pump hooked. Try not to shock load it by coming out of the water.
I'd imagine yours should last longer than mine being hit with the nitrous. It's an instant 1k rpm when it hits.
I try my hardest to not come out of the water, and if I do I try my hardest to lift off the throttle before it hits the water again
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Seriously though. I've been told by a couple people that put some serious HP to their aluminum impellers they can last
Just depends on how you treat it. Mainly keeping the pump hooked. Try not to shock load it by coming out of the water.
I'd imagine yours should last longer than mine being hit with the nitrous. It's an instant 1k rpm when it hits.
I try my hardest to not come out of the water, and if I do I try my hardest to lift off the throttle before it hits the water again
I call bullshit on the serious hp, it's simply a matter of luck and time.
Been lucky and running out of time.
I have scattered two aluminum Berkeley impellers on nothing but RPM and horsepower. It destroys more than just the impeller btw.
GT
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And that is the big reason I am going to yank my engine this fall and sell my hull. I dont think I could stomach investing more into this paticular watercraft(or maybe its my wife that cant, lol). Stainless is expensive. I would want stainless impeller, shaft, inducer and all the other yummy goodies.
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And that is the big reason I am going to yank my engine this fall and sell my hull. I dont think I could stomach investing more into this paticular watercraft(or maybe its my wife that cant, lol). Stainless is expensive. I would want stainless impeller, shaft, inducer and all the other yummy goodies.
Mag Bronze is a killer alternative. Costs a little over a third of a good stainless.
That's what I run truth be told.
GT
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And that is the big reason I am going to yank my engine this fall and sell my hull. I dont think I could stomach investing more into this paticular watercraft(or maybe its my wife that cant, lol). Stainless is expensive. I would want stainless impeller, shaft, inducer and all the other yummy goodies.
Dont sell the boat!
Ive been looking at CP's package deal. I think its a decent enough price
599.99 for an AQ shaft, an inducer, and all the machining.
Keep eyes open for a used stainless or bronze impeller.
http://www.cpperformance.com/p-395-inducer-shaft-bearing-kit.aspx (http://www.cpperformance.com/p-395-inducer-shaft-bearing-kit.aspx)
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Hhhmmmm, that is interesting.
Not familiar with AQ shaft. That is stainless?
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But then that is 6-7 hundred after tax and delivery. Then figure 3ish for a used bronze or 5-6ish for used stainless impeller. Damn it!!!
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But then that is 6-7 hundred after tax and delivery. Then figure 3ish for a used bronze or 5-6ish for used stainless impeller. Damn it!!!
I'm not an expert, but i believe the AQ shaft is the hardened shaft, it says its the 17-4 steel.
Heres what im saving my pennies to do
Buy that kit from CP. 599.99 with shipping (shipping to AZ to save on tax) 627.25
Hope to pick up a good used stainless or mag bronze impeller for around 400
Have the impeller i pick up cut down to around a C cut since i seem to really like it. Might even go a half cut smaller. May even spend a few bucks to have it detailed.
I already have a new shouldered .010 oversize wear ring that i would like to set a pump up with. IF itll work with the impeller i pick up.
I have a Dominator bowl already so i dont really know if it needs to be detailed or anything aka if its even worth my time.
See if i can get the clearances pretty tight WITHOUT cutting the thrust face of the impeller.
Will it be a built 3k dollar pump? No. But it should work well enough for me
Going to pick up another suction housing shortly, have it powdercoated then start collecting parts.
GT! Would it be worth my time trying to smooth out the casting inside the suction housing? Getting rid of the rough casting marks?
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I'm curious about an inducer... Would you see any noticeable gain in front of any impeller or just machined one??
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I'm not an expert, but i believe the AQ shaft is the hardened shaft, it says its the 17-4 steel.
Heres what im saving my pennies to do
Buy that kit from CP. 599.99 with shipping (shipping to AZ to save on tax) 627.25
Hope to pick up a good used stainless or mag bronze impeller for around 400
Have the impeller i pick up cut down to around a C cut since i seem to really like it. Might even go a half cut smaller. May even spend a few bucks to have it detailed.
I already have a new shouldered .010 oversize wear ring that i would like to set a pump up with. IF itll work with the impeller i pick up.
I have a Dominator bowl already so i dont really know if it needs to be detailed or anything aka if its even worth my time.
See if i can get the clearances pretty tight WITHOUT cutting the thrust face of the impeller.
Will it be a built 3k dollar pump? No. But it should work well enough for me
MPD (Jack) detailed my stainless impeller in '08, 3 bills. Came out like a jewel. Too pretty to hide in a ditch pump. :thumbup:
17-4 PH is a chromium-nickel grade of stainless that may be hardened by a single low temperature precipitation-hardening heat treatment. Excellent mechanical properties at a high strength level may be obtained by such treatment. Scaling and distortion are minimized.
Which Dom bowl, early or late? It always helps to clean up the leading and trailing edges of the vanes on the bowl.
Its all on the tolerances of the pump. .025 f-to-r, .012 each side. (~.025 total, per Berkeley) mines at .017 f-to-r. (was when built) :sly:
Dan'l
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Impeller will last longer than the Ford 😁
#10 spot is open!!! Go get em turbo!!!
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#10 spot is open!!! Go get em turbo!!!
lol. I cant afford to be on the list
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GT! Would it be worth my time trying to smooth out the casting inside the suction housing? Getting rid of the rough casting marks?
Unless your suction housing is especially nasty inside, probably nothing you would notice with the seat of your pants. I spent a bunch of time blending and smoothing one, front edge of the intake all the way through the suction housing to the impeller. Even remade the cleanout cover to fit nice and tight. Never got to try it, but after I was done I was told it wouldn't make much difference. And this was ALOT of work. Still have this pump sitting in my spare bedroom.
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Unless your suction housing is especially nasty inside, probably nothing you would notice with the seat of your pants. I spent a bunch of time blending and smoothing one, front edge of the intake all the way through the suction housing to the impeller. Even remade the cleanout cover to fit nice and tight. Never got to try it, but after I was done I was told it wouldn't make much difference. And this was ALOT of work. Still have this pump sitting in my spare bedroom.
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that was what i was thinking about.... since its going to be more than a little while before i can start ordering parts. I figured it woul give me something to do.
Let me ask another question. Since in my application my cleanout is not usable. Would it be worth it having it welded/capped off?
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lol. I cant afford to be on the list
Might not cost anything. Was tryin to read the rules and figure out how that empty #10 spot gets filled.
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Might not cost anything. Was tryin to read the rules and figure out how that empty #10 spot gets filled.
No it wont... but then once you're on it. Especially #10 you have to be where someone wants to race within 3 weeks.
Not to mention my engine had 218k when it went in and probably doesnt want that much nitrous through it that often to stay on the list.
It would be short lived for me, and id rather just leave it alone
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Hhhhhmmmmm, I feel a lil let down. Lol
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Hhhhhmmmmm, I feel a lil let down. Lol
lol. Now! If i didnt have a truck payment and a motorcycle payment every month... things might be different.
I do plan on rebuilding the engine shortly. Not really changing much other than boring to an iron 5.7 and forging it. Should make a bit more power, but not doing it "to go after the list" if that makes sense
Now... if you wanna send the engine from your Camaro my way.... Could be fun
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Shoot, you would rather have my boat engine then the camaro......ooooohhhh, it is a chevy/ford thing. Ok then!!! Lol
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Shoot, you would rather have my boat engine then the camaro......ooooohhhh, it is a chevy/ford thing. Ok then!!! Lol
lol yeah no kidding!
i like the fuel economy of the small blocks. because im a cheap bastard
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lol yeah no kidding!
i like the fuel economy of the small blocks. because im a cheap bastard
Lol, ya, cuz you get kick ass gas mileage hitting that nos button.
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Lol, ya, cuz you get kick ass gas mileage hitting that nos button.
youd be shocked lol
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Seriously though. I've been told by a couple people that put some serious HP to their aluminum impellers they can last
Just depends on how you treat it. Mainly keeping the pump hooked. Try not to shock load it by coming out of the water.
I'd imagine yours should last longer than mine being hit with the nitrous. It's an instant 1k rpm when it hits.
I try my hardest to not come out of the water, and if I do I try my hardest to lift off the throttle before it hits the water again
I call bullshit on the serious hp, it's simply a matter of luck and time.
Been lucky and running out of time.
I have scattered two aluminum Berkeley impellers on nothing but RPM and horsepower. It destroys more than just the impeller btw.
GT
IMO, its a crap shoot with aluminum and high HP. I cracked a brand new aluminum with about 500 HP (cracked one "blade" at the hub with no mark from it hitting anything) replaced with another one and never had a problem after that. I got lucky and saw the crack while checking the loader before it got too bad and came apart. You might get a good one that will take it, and you might not. Is it worth the risk to YOU, that's the question. ;)
that was what i was thinking about.... since its going to be more than a little while before i can start ordering parts. I figured it woul give me something to do.
Let me ask another question. Since in my application my cleanout is not usable. Would it be worth it having it welded/capped off?
I wouldn't worry about it. With the exemption of a good/properly set up loader, your best investment in time or money will be behind the suction housing. If you weld it shut, what about when you want to swap your good pump into another hull someday where it would be useable, or you want a pop off valve ? Some places use to sell a "tight fit" cleanout cover, kinda like what I made. If your worried about it you might try finding one of those. That way its still removable (like mine) if someday you need it, and you don't ruin a good suction housing.
If you really need something to do...... Grab a sawzall and cut all the "extra" weight you can find out of the boat. It will help more than messin with the suction housing.
If you still have any doubts, I'm sure GT will be along shortly to help explain how much time and effort I wasted in that suction housing. LOL But it looks cool. 8)
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So, I was on ebay looking at new impellers. Specifically American turbine ones. Looked at their stainless (949 brand new btw). Then i stumbled across one for a 312 pump it appeared different.
Started thinking maybe i had the wrong impeller. So i called up AT
The guy was really nice. We bullshitted for a few minutes. Come to find out he has an LS addiction as well...
Anyways. I told him about my cavitation with the AT impeller vs with the berkeley impeller.
Told him pretty much everything in this thread, told him we cut it down to tighten the clearances up more and everything. He said that he didnt think that would be the issue but to try to thin it out/bullet nose it.
But he said he has seen this happen a few times, and this could be very well what my problem is.
His idea was that the AT Internal Diameter is physically larger than the Berkeler impeller and because of this it demands more water than the berkeley. He says he has seen pumps suck the suction dry for a brief second on the hit from idle because its not being fed water and it just doesnt recover until the boat is on plane. Said that it seemed to be a much more pronounced issue with a stock berkeley nozzle vs a place diverter or other smaller nozzle and without an inducer. He said if i can restrict the exit of the nozzle down a bit, he thinks that it would help.
He said to send him my impeller if i want to and he will be happy to check it out. Considering i didnt buy it from him, the customer service is awesome.
I thought this was interesting information and sounded valid enough to me. Regardless, its getting a diverter. When i put it on, i guess ill have to try it to see if it helped. Just wanted to share. I didnt even think about calling them up.
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lol. I cant afford to be on the list
U can do it
Sent from my iPhone using SoCal Jet Boats
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So as I'm reading through this interesting thread I click the link to the CP shaft and bearing kit for $600.
I bought a hardened shaft from our local Jet expert's shop for $1000 I believe a couple of years ago.
Then I bought the high end Inducer from him, HCM comes to mind, for $450.
I got what I wanted and was happy to spend the money with this guy. I won't mention his name cause the last thing I want to do is throw him under the bus.
Somebody tell me what I got is way better than the CP stuff :sly:
I also have a quality Stainless HTP Hi Helix impeller race tuned by Duane, very happy with the $1250 spent.
B1 Loader $300
Then there's everything on the outside, bowl, PD ...
Damn this crap is expensive. I buy 1 piece at a time and try not to think about the total spent.
Flying across the water full grin, so worth it! 8)
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So as I'm reading through this interesting thread I click the link to the CP shaft and bearing kit for $600.
I bought a hardened shaft from our local Jet expert's shop for $1000 I believe a couple of years ago.
Then I bought the high end Inducer from him, HCM comes to mind, for $450.
I got what I wanted and was happy to spend the money with this guy. I won't mention his name cause the last thing I want to do is throw him under the bus.
Somebody tell me what I got is way better than the CP stuff :sly:
I also have a quality Stainless HTP Hi Helix impeller race tuned by Duane, very happy with the $1250 spent.
B1 Loader $300
Then there's everything on the outside, bowl, PD ...
Damn this crap is expensive. I buy 1 piece at a time and try not to think about the total spent.
Flying across the water full grin, so worth it! 8)
I hope its not better. I'd be pissed lol
Heres another picture from CP's site. Looks like a DPS inducer
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I call bullshit on the serious hp, it's simply a matter of luck and time.
Been lucky and running out of time.
I have scattered two aluminum Berkeley impellers on nothing but RPM and horsepower. It destroys more than just the impeller btw.
GT
X2 last year at parker got a bad vibration after a hard pass, motor only about 500 hp or so but neglected pump upgrades due to funds
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An "AQ shaft" is an abbreviation for the trade name Aquamet, a proprietary alloy, which was the first high-strength marine prop shaft material produced. 17-4 stainless has similar mechanical properties to Aquamet, but was not commercially available until some time after. Performance shafts started being produced from the much more economical 17-4 SS, however the "AQ shaft" name had stuck.
You can read about Aquamet at http://www.aquamet.com/gradecomparison.nxg
When someone says "AQ shaft," what they mean is a high-performance shaft of usually 17-4 stainless, but it could also be the real deal, however rare that may be.
You can tell if you have the good shaft by if a magnet sticks to it. 17-4 stainless steel is magnetic.
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So a stainless one is a waste of money if I'm only pushing 350-400 hp?
Yes. You would see a gain from detailing your good, usable aluminum impeller. Basically detailing will make it bite approximately equivalent to an impeller that is one cut size larger because of reduced cavitation.
Detailing should reduce RPM. Cutting an impeller smaller increases RPM. If detailing the impeller increases RPM, damage has been done to reduce efficiency.
I'm curious about an inducer... Would you see any noticeable gain in front of any impeller or just machined one??
Yes. Where you will see the most gains would be at the hit.
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Steve,
Now I am seeing the whole picture. Been a little overwhelmed at work and it's hard for me to keep track of what everyone is doing.
GT is absolutely spot on when he said machining the front of the hub is killing the water flow. The water flow just can't recover from crashing into the huge wall that was created by cutting the front of the hub off. As the water is deflected off, a large portion of the blades are shadowed from water flow.
The only way you can save that impeller is to machine and hand detail the transition between the shaft and the hub.
I now believe what you are experiencing is a combination of pluses and minuses. You change the cut size, the leakage through the wear ring clearance, and you change the turbulence generated at the inlet eye of the impeller. All of these things affect pump performance and you are not getting a true apples to apples comparison.
I wouldn't waste any $ on postage to ship that impeller to AT. What the guy at American Turbine said about the cross-section area and flow might normally be a factor, however, in this case it is not. You can see what the guy at American Turbine is talking about when you look at the cut-away pictures of their pumps showing the venturi shape. This all-important venturi shape starts with a large area in the suction housing in front of the inlet eye of the impeller. The cross-section quickly reduces in the impeller and continues into the bowl. Then the cross-sectional area expands again, right before the droop.
What happens inside the pump is, the water is mechanically accelerated by the impeller. The water is at a high-velocity, but at a relatively low pressure. The expansion of the cross-section area right before the droop causes the water to slow, but the energy is converted into pressure before the final restriction of the nozzle.