Ideas of how to gain mph?

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billymachete

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« on: May 17, 2017, 08:29:21 PM »
I have a 71 horizon with a 395hp olds 455 just put in comp 268 and air gap manifold. Was supposed to have had a 454 BBC ready this season but it's just not going to work so I put olds back in. I have cleaned up impeller and put a new wear ring on the jacuzzi pump. Pump has divertor and droop. Does anyone have ways I could get some more mph out if what I have. I believe it tops out right around 55-58.


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BCouey

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« Reply #1 on: May 17, 2017, 09:58:56 PM »
Ride plate?


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69SANGERFLAT

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« Reply #2 on: May 17, 2017, 10:27:08 PM »
Finish the bbc


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billymachete

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« Reply #3 on: May 18, 2017, 12:39:14 AM »
Unfortunately I won't have BBC done until next season...ride plate check I believe I have one on the Berkeley pump I have ready to be rebuilt


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coggy

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« Reply #4 on: May 18, 2017, 12:57:52 PM »
$$$$

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« Reply #5 on: May 18, 2017, 03:46:27 PM »
Unfortunately I won't have BBC done until next season...ride plate check I believe I have one on the Berkeley pump I have ready to be rebuilt


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That ride plate would most likely bolt to the shoe on the Berkeley intake.  Place Diverter makes one that bolts to their full-droop, but won't work on a Jacuzzi without an adapter.

I wouldn't spend any money on the Olds/Jacuzzi combo.  Enjoy it for this season while you get the Chevy/Berkeley combo ready to drop in.
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« Reply #6 on: May 18, 2017, 04:23:46 PM »
Man Olds haters lol ... I take that Oldsmobile when u make the bbc swap


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Flusher

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« Reply #7 on: May 18, 2017, 04:55:00 PM »
Man Olds haters lol ... I take that Oldsmobile when u make the bbc swap


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Not hating here.

The OP has already started accumulating parts for a BBC/Berkeley swap.  Just trying not to advise moving backwards.

No bolt-on parts short of NOS will net any significant gains.  Adding a shoe and ride plate is a big job right at the beginning of the season.  It would be better to just move forward with the Berkeley swap at that point.  That could cause him to miss this season.

I'm sure there is some MPH in tuning hardware, there just aren't any options without serious time and money.

Maybe a diverter is available where most parts will be compatible with both pumps, assuming the boat doesn't already have one.  It is possible to make an adapter to run a Berkeley droop and diverter on a Jacuzzi.  This would probably be the best performance per dollar spent and not "waste" a lot of money after the swap.
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« Reply #8 on: May 18, 2017, 06:15:24 PM »
If he hasnt run it with the new wear ring, he should notice a difference once he runs it. I know I did.

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« Reply #9 on: May 18, 2017, 06:40:22 PM »
I have a 71 horizon with a 395hp olds 455 just put in comp 268 and air gap manifold. Was supposed to have had a 454 BBC ready this season but it's just not going to work so I put olds back in. I have cleaned up impeller and put a new wear ring on the jacuzzi pump. Pump has divertor and droop. Does anyone have ways I could get some more mph out if what I have. I believe it tops out right around 55-58.


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Please post pictures of your setup.  So that I am not speculating, need to see what you are working with.  Pictures of the pump, especially from the side.  Pictures of the intake opening under the boat, particularly the transition between the fiberglass and the aluminum intake.

What diverter/droop is installed on which pump?
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billymachete

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« Reply #10 on: May 22, 2017, 08:36:38 AM »
I put new wear ring in end of last season...I actually have a Nitrous kit I was thinking about throwing on lol...anyways jacuzzi wj with droop and divertor. What am I looking for in regards to the intake of the pump to optimize performance?


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jamiemwedmore1234

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« Reply #11 on: May 22, 2017, 02:45:37 PM »
Take large amount of cash stick it in the garbage disposal turn on the water and boom this is how you successfully waste a bunch of money that's how I got more mph out of mine


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« Reply #12 on: May 22, 2017, 07:42:16 PM »
Measure out ten inches from center, both sides, draw a line from bow to transom, measure ten inches from that line out on both sides. Now cut with skillsaw. Lift the cut part up some where between 6 and 8 inches, build side walls. whalla instant speed!
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« Reply #13 on: May 23, 2017, 02:37:25 PM »
Back on topic:

You don't have much hardware to work with i.e. shoe, ride plate, loader.I will try to make some recommendations that aren't cost prohibited.  Getting every last MPH out of your combination is an exercise in attention to detail.

It doesn't matter what brand or model pump you have, if it is starved for water, thrust is down.  Feeding the pump really begins with the installation of the intake.  Sometimes the intake is set so bad that the only way to fix it is to reset it.  Resetting your Jacuzzi is counterproductive to your plans for the boat and time constraints of the season.

I am not the Jacuzzi master, all of my pictures are of Berkeley style intakes.  The concept will be the same.

Pumps get the majority of water from the keel.  Shoes and loaders help to even the velocity of flow across the entire intake opening.

You want a nice smooth transition between the fiberglass keel and the aluminum intake.  You want to match the elliptical radius of the intake with that transition.  You do not want the transition to dive away too quickly or the flow will detach from the surface.  You also don't want to carry the radius too far forward.

On a Berkeley style intake, blend the opening approximately 8" to 9" from the front edge of the rock grate recession.  Too short and the water will separate.  Too far and the pump won't load as hard as it could.  I don't know what that corresponds to on a Jacuzzi, but it will give you an idea.

You are not trying to change the shape of the hull, just blend it in.  Be careful that you don't sand all the way through the glass right in front of the intake.  Lastly, fill any exposed screw heads.

We use Bondo Glass for moderate filling.  Regular body filler is fine for small imperfections.  Preparation is key to adhesion.  Primed with an 80 grit scuffed finish is most desirable.

Remove any gouges and imperfections from the intake fins.  These will cause cavitation and lower the impeller inlet eye pressure, reducing thrust. I use a 4" grinder with a 36 grit flapper sanding disk and a rough cut file.
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billymachete

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« Reply #14 on: May 23, 2017, 07:04:45 PM »
It's getting hot here in Phoenix and I've actually taken on the task of completely re wrong boat this week. But tonight while I'm working I'll get some pics of the underside by pump and also take a look at the area and hopefully get an idea of what you're talking about. I know the Holmes horizon isn't the best hull for speed and I've considered purchasing a different boat but I've always been one to make the most of what I have laying around, and in this case it's this boat with an olds 455 this year. Once this season is over I'll get the 454 put in with a split bowl Berkeley I have and that will hopefully be worth a bit more speed. I'll get the pics posted tonight after I've got some wiring done

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« Reply #15 on: May 23, 2017, 08:39:30 PM »


...I have cleaned up impeller and put a new wear ring on the jacuzzi pump. Pump has divertor and droop. Does anyone have ways I could get some more mph out if what I have. I believe it tops out right around 55-58.

If you have any nicks and dings in the impeller or bowl vanes, cavitation will originate at every imperfection and cause the pump to slip, hurting the launch and overall efficiency.

I find it is best to file the leading edges until straight, then sharpen the bottom surface of the vanes.  This applies to both the bowl and the impeller.  If you need to clean up the top surface of the vanes, don't remove too much material or change the shape.

Minor damage cleans up fairly easy with a file.  Substantial damage in the bowl can be touched up, but efficiency is sacrificed the more you cut the vanes back.  The impeller on the other hand, I have cut the leading edges back 1/2" without a change in RPM.  This is for mixed flow impellers only.  Axial flow impellers are dependent on blade area.

I wouldn't recommend detailing the bowl and impeller since you are changing it next season.  If you were feeling ambitious, you could try your hand at detailing them yourself.
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billymachete

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« Reply #16 on: May 23, 2017, 08:41:38 PM »

If you have any nicks and dings in the impeller or bowl vanes, cavitation will originate at every imperfection and cause the pump to slip, hurting the launch and overall efficiency.

I find it is best to file the leading edges until straight, then sharpen the bottom surface of the vanes.  This applies to both the bowl and the impeller.  If you need to clean up the top surface of the vanes, don't remove too much material or change the shape.

Minor damage cleans up fairly easy with a file.  Substantial damage in the bowl can be touched up, but efficiency is sacrificed the more you cut the vanes back.  The impeller on the other hand, I have cut the leading edges back 1/2" without a change in RPM.  This is for mixed flow impellers only.  Axial flow impellers are dependent on blade area.

I wouldn't recommend detailing the bowl and impeller since you are changing it next season.  If you were feeling ambitious, you could try your hand at detailing them yourself.




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billymachete

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« Reply #17 on: May 23, 2017, 08:50:07 PM »



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I actually did this at the end of last season when I replaced the wear ring. I messed with the bowl a bit but only ground down big imperfections in it and then took all nicks era out of impeller. Boat was faster and it didn't seam to "slip" when I gunned it with divertor down. Actually got out of water much better. Here are photos of intake area. Everything seems smooth and "blended". Let me know if any areas can be improved


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« Reply #18 on: May 23, 2017, 08:56:50 PM »
These are pictures of intake area. Only thing  could see or feel that we're mentioned we're a couple exposed screw heads. I'll fill those with some body filler and sand down with some 1000 tonorrow


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« Reply #19 on: May 23, 2017, 09:52:43 PM »
Looking at the picture of your pump, you have the old nozzle with the grappling hook reverse shoot.  You might be losing a little speed if the reverse shoot is dragging in the water.

You can trim the reverse shoot up so that it doesn't drag as bad, but you will compromise reverse thrust.  You may consider upgrading to the modern nozzle.  It will have less drag and it is compatible with your future plans to upgrade.

To optimize lift in a boat equipped with a ride plate, we would wedge the droop down so that the lower steering pin 3/4" above the ride plate.

Without a ride plate, there is no point of reference.  Wedging your droop could also cause the reverse shoot to drag worse you will have to see if that is feasible for your boat.

You might want to consider diverter stops to limit travel up and down (picture).  Some testing will be required to figure out exactly what nozzle trim angle will work best for your boat.

When measuring nozzle angle et al, zero a digital level on the keel, just in front of your intake.  All measurements will be taken from that point.

People really underestimate hardware configuration.  It can make or break performance by 5 to 10 MPH or more.  When you move forward with your swap, definitely install a shoe and ride plate.  I'm not sure about a full setback in your boat.  I would at least cut the opening so that the intake is all the way back against the transom.

Hope this gives you some ideas to get started.

Good luck,

Joe
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« Reply #20 on: May 23, 2017, 10:01:37 PM »
These are pictures of intake area. Only thing  could see or feel that we're mentioned we're a couple exposed screw heads. I'll fill those with some body filler and sand down with some 1000 tonorrow


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I would lose the rock grate.  I'm not sure if MPD is still making loaders for Jacuzzi pumps.  If you are feeling a little spendy and you can find one, a loader is worth while investment.

A slightly rougher surface on the bottom has less fluid friction.
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« Reply #21 on: May 23, 2017, 10:13:31 PM »
Looking at the picture of your pump, you have the old nozzle with the grappling hook reverse shoot.  You might be losing a little speed if the reverse shoot is dragging in the water.

You can trim the reverse shoot up so that it doesn't drag as bad, but you will compromise reverse thrust.  You may consider upgrading to the modern nozzle.  It will have less drag and it is compatible with your future plans to upgrade.

To optimize lift in a boat equipped with a ride plate, we would wedge the droop down so that the lower steering pin 3/4" above the ride plate.

Without a ride plate, there is no point of reference.  Wedging your droop could also cause the reverse shoot to drag worse you will have to see if that is feasible for your boat.

You might want to consider diverter stops to limit travel up and down (picture).  Some testing will be required to figure out exactly what nozzle trim angle will work best for your boat.

When measuring nozzle angle et al, zero a digital level on the keel, just in front of your intake.  All measurements will be taken from that point.

People really underestimate hardware configuration.  It can make or break performance by 5 to 10 MPH or more.  When you move forward with your swap, definitely install a shoe and ride plate.  I'm not sure about a full setback in your boat.  I would at least cut the opening so that the intake is all the way back against the transom.

Hope this gives you some ideas to get started.

Good luck,

Joe




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billymachete

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« Reply #22 on: May 23, 2017, 10:14:59 PM »
I'm not sure what pump set back means but I see it a lot or mentioned a lot . What exactly do I need to be looking for as far as the reverse bucket causing drag and what to I trim? Do I want the bucket  to open further than it does etc?


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« Reply #23 on: May 24, 2017, 06:38:29 AM »
I'm not sure what pump set back means but I see it a lot or mentioned a lot . What exactly do I need to be looking for as far as the reverse bucket causing drag and what to I trim? Do I want the bucket  to open further than it does etc?


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It's not the bucket but rather the part where the water flows backwards when you close the bucket when putting in reverse. You can mill it down to reduce drag. But for every action you will have a reaction. Most likely you will lose most if not all reverse capabilities.

I have mine milled down and reverse is gone but I also don't need reverse and was looking for every mph I could get.

With your package I don't see it making any noticeable difference. You're not running speeds where it has much of an effect. You have a nice cruiser, enjoy it for what it was designed to be and put the effort into the Chevy/Berk package.
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« Reply #24 on: May 24, 2017, 06:54:54 AM »
Agreed. Drive the piss out of it this summer. Enjoy it. Then do winter upgrades.👍

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