Freestyle Impeller spacer question (should or shouldn't?)

pigpen

pigpen

Location
kalispell
I'm about to put my new impeller on and I'm curious if I should run this spacer I had on previously. The spacer is about 5mm and seems like a lot. I was always under the assumption that with a hooker it was cut back to get closer to the stator? Looking for a little input for the pump tuning on this. It's a 9/15 hooker, WW cone, stock bore nozzle.


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Roseand

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
Completely depends on your setup down to even what intake grate you run. Everyones setup will vary. With a tnt pipe on my 701 I had to space it like 5mm from the stator vanes to reduce pump load. I went from it almost touching the vanes to 5mm away and it made a significant difference. What motor and pipe are you running?

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pigpen

pigpen

Location
kalispell
781 62t/61x, dual 38's, limited b pipe, lightened flywheel.
7e8e8a301bac6133baedd638c4dab404.jpg

That's with no spacer, it looks like it sits 4-5mm from the stator.


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Roseand

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
What's your altitude? That's basically what I had mine set to. I had my hooker cut back 5mm more and ended up having to space it back out like it would be from impros to begin with lol.
Unless you're at a real high altitude I'd think you'd want more than a 9/15..

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pigpen

pigpen

Location
kalispell
Roseand said:
What's your altitude? That's basically what I had mine set to. I had my hooker cut back 5mm more and ended up having to space it back out like it would be from impros to begin with lol.
Unless you're at a real high altitude I'd think you'd want more than a 9/15..

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Click to expand...

5400ft lol


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High Speed Industries

High Speed Industries

Your one stop shop for quality parts @highspeedind
Location
Lake Havasu City, AZ
I would run the same spacer installed exactly the same as it was before. If you change impellers and spacers how will you know which one is making the difference?

I suggest one change at a time so you can see what works and what doesn't.

How many rpm are you currently running?
 
pigpen

pigpen

Location
kalispell
Rdrttoy said:
I would run the same spacer installed exactly the same as it was before. If you change impellers and spacers how will you know which one is making the difference?

I suggest one change at a time so you can see what works and what doesn't.

How many rpm are you currently running?
Click to expand...

I didn't change pitches just put a fresh impeller. Still a 9/15, old one just had some bumps and bruises. The old one wasn't bad it just felt like there shoulda been more on the bottom end.


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kdog701

kdog701

Location
Georgia
Mine rips on bottom but top sux and can't get but 6500 rpm and have no idea my spacer or if I have one lmao...guess I need to check ...I have TNT chamber and such but still carb tuning


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john zigler

john zigler

Vendor Account
Location
wisconsin
Impeller closer to the veins will "load" the pump harder. By spacing it away, it will slip some. I try to always run as close to the veins as possible for maximum efficiency. The only reason to space it away is if your engine cannot pull your impeller.

I would for sure try without the spacer.

In your pic, your stator looks to be an OE Yamaha? You may also want to try a stock pump cone, and even nozzle ID, as I think you are not building enough pressure with your set up / pitch combo.
 
pigpen

pigpen

Location
kalispell
john zigler said:
Impeller closer to the veins will "load" the pump harder. By spacing it away, it will slip some. I try to always run as close to the veins as possible for maximum efficiency. The only reason to space it away is if your engine cannot pull your impeller.

I would for sure try without the spacer.

In your pic, your stator looks to be an OE Yamaha? You may also want to try a stock pump cone, and even nozzle ID, as I think you are not building enough pressure with your set up / pitch combo.
Click to expand...

Ya oem 144, I can try swapping cones with my superjet too and see what happens.


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Pro-pulsion

Pro-pulsion

Location
Ontario, Canada
I wonder if it is not an issue with power delivery (engine response/holeshot/bottom end) as much as it is pump efficiency (hookup and processing). A nice little free mod that will help a good bit with hookup is blueprinting the stator section of the pump. All those little casting bosses, rounded edges on the vanes and the rough textured finish make for a lot of bubbles and water separation. If you look at your pump stream about 15-20 feet behind you when going from low speed to immediate full open, and you see larger bubbles surfacing instead of millions of little ones it means you are boiling the water from over spinning or under-loading your prop. A shot pump seal, worn out wear ring, worn out impeller, or too low of a pitched impeller will do this and likewise reduce hookup quite noticeably. I am running a Hooker 9/15 with blueprinted pump and R&D pump stuffer to compliment the large hub impeller and love it. No issues with pump efficiency at all. I also recently changed out my stock reduction nozzle with a Protec 85.5mm exit diameter and gained a little bit more :)

Oh I should also mention, I had to include 2mm of shims behind the stock rubber coated OEM shim. The only reason was because when tightened up the impeller would lock up the pump, it required two 1mm shims installed for the impeller to spin freely, I left it at that. Like john zigler mentioned, I wanted to keep my impeller as close to the vanes as possible for maximum efficiency.
 
Last edited:
pigpen

pigpen

Location
kalispell
Pro-pulsion said:
I wonder if it is not an issue with power delivery (engine response/holeshot/bottom end) as much as it is pump efficiency (hookup and processing). A nice little free mod that will help a good bit with hookup is blueprinting the stator section of the pump. All those little casting bosses, rounded edges on the vanes and the rough textured finish make for a lot of bubbles and water separation. If you look at your pump stream about 15-20 feet behind you when going from low speed to immediate full open, and you see larger bubbles surfacing instead of millions of little ones it means you are boiling the water from over spinning or under-loading your prop. A shot pump seal, worn out wear ring, worn out impeller, or too low of a pitched impeller will do this and likewise reduce hookup quite noticeably. I am running a Hooker 9/15 with blueprinted pump and R&D pump stuffer to compliment the large hub impeller and love it. No issues with pump efficiency at all. I also recently changed out my stock reduction nozzle with a Protec 85.5mm exit diameter and gained a little bit more :)

Oh I should also mention, I had to include 2mm of shims behind the stock rubber coated OEM shim. The only reason was because when tightened up the impeller would lock up the pump, it required two 1mm shims installed for the impeller to spin freely, I left it at that. Like john zigler mentioned, I wanted to keep my impeller as close to the vanes as possible for maximum efficiency.
Click to expand...

Great info here, I'll have to see what the pump is doing once I get the ski back together. Appreciate the info! My prop spins freely still with no shims ahead of the rubber seal so I think I'm gonna try that first and go from there.


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