Super Jet Pump-nozzle-impeller pitch

FlightPlanDan

Don'tTrustAfartAfter50
I realize this is tech stuff or experience stuff....Assume I have neither

A "very" reputable builder told me that a bored nozzle would really "wake-up" my 12/17 skat swirl.
Bored nozzels that are still set up for the stock bilge are a bit harder to come by than for dual cooling boats.
When one came available, I grabbed it. It was bored a bit larger than the builder suggested, but I grabbed it. 85.5mm.

Well, being the non listening guy that I am, I installed the nozzle and a different impeller at the same time. (a 9/15 hooker)

This didn't work well. I felt a good hit, but it immediately decayed into what seemed like a loss of power.
The hooker was small on the O.D. by (eyeball 1mm per side..total 2mm) which would cavitate anyway.
I put the skat back in.
It's not perfect and neither is my wear ring. But I borrowed a bud's wear ring section of a 144 pump to verify.

Question: with a nozzle bored this big, would a higher pitch impeller do a better job even at low end?

In my mind it will work, but, as you know, my mind is warped. The higher pitch prop moves more water if it has somewhere to go. Stock nozzle - nowhere to go=loss of low end. Am I wrong?

I'm about to try a 14/22 skat.

your thoughts please. Through experience or science!

Dan

Standard bolt-ons, b-pipe, enhancer etc...not ported/polished, 190 compression ADA head. 701.


I can always go back to the stock nozzle. But I really want to know what will work with the 85.5 nozzle.
And I'm willing to experiment to find out. Thought somebody might know.
 
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AtomicPunk

Lifetime bans are AWESOME
Site Supporter
Location
Largo, Fl
Dan, I ran that impeller with 85.5 and it hit really nice in the surf. The only difference was a ProTec Mach pipe and stock head milled to 165 psi.
 

QJS

X-
Location
GONE
I've run 9/15 hookers on similar engines with 85mm nozzles with no problems, its also cheaper to make your nozzle suit the prop rather than your prop suit your nozzle.
Chris.
 

Waternut

Customizing addict
Location
Macon, GA
That 14/22 pictch prop will be a dog IMO. I run a 9/15 hooker with an 85mm nozzle and a stubby cone and it works great. Based on others experience/reports, the 13/18 skat swirl is close to the 9/15 hooker which would therefore make your 12/17 swirl a slightly shallower pitched prop and better for bottom end performance. The hooker and smaller nozzle will offer better hookup but at the expense of low end grunt. Rider style and preference will play a bigger role in what you want.
 

FlightPlanDan

Don'tTrustAfartAfter50
UPDATE:

Water tested 14/22 3mm cutback skat today.
It performed well enough to leave it in for the big waves this weekend. Only a bit of "delayed" hit at the bottom. It powered thru the rpm range with spunk. I was expecting it to be a dog, but , it was better than my 12/17 (in need of refurb).

It did well! IDK.
 
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