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Do i need a droop

Blackmagic94

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18' Carrera with the JBP Xclerator drive conversion


best run on a AA impeller


5100 rpm
70.8 mph at 3000 feet above sealevel
300FA707-F39A-46D4-852D-CD9648376620.jpeg
56B56BA4-CBF8-4DD8-99F2-307B00DCE9DD.jpeg
 

ultrajet

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I have a similar set back dominator jet with trim, 2* back cut shoe and ride plate . Adding the droop increased performance
 

Dalton

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At least it looks cool


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brgrcru

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You have a short droop on there now.
I think you are in the ball park , with rpm and speed for a AA cut.
A/b cut will get you a few mph.
The bottom of the boat needs to be straight for bigger performance gains .
You can get a straight edge and check the last three feet of running surface .
If you have a gap . Then the haul has a hook which most boats have .
There are exceptions , gull wings , daytonas , tunnel hauls . But even those at times need bottom work.
 

Dalton

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You have a short droop on there now.
I think you are in the ball park , with rpm and speed for a AA cut.
A/b cut will get you a few mph.
The bottom of the boat needs to be straight for bigger performance gains .
You can get a straight edge and check the last three feet of running surface .
If you have a gap . Then the haul has a hook which most boats have .
There are exceptions , gull wings , daytonas , tunnel hauls . But even those at times need bottom work.
How much HP would you say?


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Blackmagic94

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You have a short droop on there now.
I think you are in the ball park , with rpm and speed for a AA cut.
A/b cut will get you a few mph.
The bottom of the boat needs to be straight for bigger performance gains .
You can get a straight edge and check the last three feet of running surface .
If you have a gap . Then the haul has a hook which most boats have .
There are exceptions , gull wings , daytonas , tunnel hauls . But even those at times need bottom work.
So would a bigger droop help get the hull out of the water so if there is a hook it’s less critical of an issue
 

brgrcru

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So would a bigger droop help get the hull out of the water so if there is a hook it’s less critical of an issue
I don't think a bigger droop , is going to make a noticeable difference.
You might gain a little . I think cutting the impellor to an A or a/b . Would make bigger gains .
 

Blackmagic94

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I don't think a bigger droop , is going to make a noticeable difference.
You might gain a little . I think cutting the impellor to an A or a/b . Would make bigger gains .
Already had it cut by Tom to an A just need to get some new numbers on it.
 

Dalton

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Does A, A/B mean higher RPM? Can your internals handle that?


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Blackmagic94

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Does A, A/B mean higher RPM? Can your internals handle that?


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My internals are fine for higher RPM, im hoping to turn 5300-5500 out next trip but we shall see.
 

DoughBallin14

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You could always order a set of different degrees wedges and play with your small droop nozzle you have now. I bought some a few years back and found a degree that worked best for my family cruiser... i had found some cheaper but can’t remember where but better then a few hundred for a nozzle

 

Blackmagic94

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You could always order a set of different degrees wedges and play with your small droop nozzle you have now. I bought some a few years back and found a degree that worked best for my family cruiser... i had found some cheaper but can’t remember where but better then a few hundred for a nozzle

What does a wedge do that trimming the place diverter does not?
 

DoughBallin14

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What does a wedge do that trimming the place diverter does not?
Well now that i think more about your question and end goal to get your nozzle lower to hopefully lift the boat up. The wedge would probably do nothing for you that your trim couldn’t do.

I suggested it from my scenario because with my droop and place diverter all the way down i still had to much bow lift and would get a lot of porpoising at cruising to top speed. I added the 3* wedge pointing down and dropped my ride plate a 1/4” and it took that problem almost completely way.
 

J 2

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We're talking about thrust height, where the bottom pin circled in the pic is in relation to the ride plate. That is the wrong pin btw, to long causing some drag I doubt you'll feel. I cropped the pic to give you an idea, however to measure use a straight edge like the bottom pic. This was my Daytona, my research found this boat likes the bottom pin of the droop to be 3/4-1" above the ride plate. Due to the way the intake was set by a previous owner I wedged it down 6 degrees to get the height right. The Place Diverter gave me all the up & down I needed. This was the sweet spot for this boat, ran hard & straight feeling very comfortable at speed. A full droop is 8.5 degrees vs 2.5 in the mini droop which is what you're running, not 100% on JBP's product I assume it's the same as the PD mini.

A inexpensive experiment would be to do what DB14 describes he did. I also have done the same thing to my 21' open bow cruiser jet. Wedge it down and see how it runs.
Thrust Height RD (2)_LI.jpg
Thrust Height.jpg
 

Blackmagic94

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Never thought about the pin causing drag. Can that be replaced with a flush one and is it a huge pita.

I’ll measure the distance
 
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