What is this impeller for?

[Swooperjet]

I just pulled the pump off of my parts sn to switch out with the one on my ski. I've been cavitating pretty bad, so I was going to try this other pump and impeller. Anyways, pulled it apart and the impeller is a Skat 12/20. Is this pitch for low end or top. It seems to me like it would be top, but I'm unsure.
I'm running a 701 with a dry pipe. I want bottom end....?????
Thanks in advance for any info.

 

[Motorheads5]

I'm running a 15/20 in a js 550/650 conversion and it has gobb's of lowend that 701 you are running has more power than my kawi 650 I'd run it at least the yami pump's are easy to change impeller's in go for it!

 

[Cross]

I'm running a 15/20 in a js 550/650 conversion and it has gobb's of lowend that 701 you are running has more power than my kawi 650 I'd run it at least the yami pump's are easy to change impeller's in go for it!

Remember that your pump is a 140mm while the yami stock pumps are 144mm. the pitch of the props are not comparable. A 12/20 is more of a top end prop. Something like a 12/15 or so would be ideal.

 

[Swooperjet]

But wouldn't it still hit about the same on the low end because of the "12" portion of the pitch.....or is the 20 just way to high period?
I know abosultely squat basically about how the pitch works.

 

[Swooperjet]

Bump.....

Thanks to both of you guys for your input. I appreciate it.

Can anyone confirm for me solidly though wheter this would hit good at all low end so it would be worth trying out since swapping the pumps is easy, or is it just definately not worth trying it for low end hit?

 

[Motorheads5]

trust cross he is more of a tech type than me I am a scrounge, however I am not scared lol

 

[Cross]

What prop were you running before?

 

[Swooperjet]

What prop were you running before?

I haven't pulled that pump apart to check actually. I was going to, but after I saw the 12/20 on the spare pump, I decided to hold off on pulling the pump on my ski till I got some input on this.
I think it's a S/C, but I don't know what pitch. It was on my ski when I got it. The ski did have a 650 before I swapped motors, and it hit pretty good then. But since I dropped in the 701 it seems to cavitate a little more. I'm going to swap out my ride plates in the morning, so I might just go ahead and pull the pump to see what exactly I have on there now.

 

[Cross]

Its hard to give you any input on the differences between the props with out knowing the pitch. Once you pull that pump, someone can give you some info.

 

[Swooperjet]

Thanks. I'm just going to wait for a few weeks and get that new Hooker anyway.
I didn't really want a comparison with my current prop though, because I know how it performs. I just wanted to know if anyone has run one with that Skat's pitch, and if it would hook up low end.
I've seen a lot of threads though with info about pitch similar to what you (Cross) posted initially. So I'll go with that. You confirmed what I kind of thought anyway about that being more of a racing or top end pitch. Thanks. I appreciate the help.

 

[SUPERTUNE]

The 650 based superjet pumps used a plastic exit nozzle...@85mm I.D.
If you dropped in a 701, you might be spinning the prop some, and you do state that.
701 based superjets have all come with an aluminum exit nozzle nozzle and are resized @ 82mm I.D. Before you go about swapping old impellers around, use the stock 701 nozzle in place of the 650 nozzle. This may not help bottom end, but then again it will if your slipping the prop...

 

[Swooperjet]

Both of my pumps are from 650 skis, so I don't have an aluminum nozzle. (Hook me up!!):sneaky:
I do need to get 2 of them actually. My buddy needs one too since he swapped to a 701 also. If anyone has a couple spares laying around....give me a shout.

I just switched out pumps for the hell of it. We're heading out to the lake, so I thought I'd just give it a shot. I'm taking my original pump with so I can swap them back if that 12/20 totally sucks.

I did pull my main pump apart, and it has a S/C 14/17 on it.

 

[Waternut]

I think one thing that confuses a lot of people is that impeller pitch is not the only contributing factor. Hub size, blade design, blade length, and prop finish all play a big role. This is why the swirl 12/17 hits harder on the bottom end than a 9/17 straight blade prop. I went from a 15/20 straight blade to a 12/17 swirl and you could swear I switched from a 550 motor to 750 motor overnight. It literally made more difference than a stock ignition to total loss. 3° alone can't make that much of a difference.

Without truly knowing the two props involved, I don't think we can tell what the prop is designed for.

 

[Swooperjet]

Problem is solved. I rode the ski for about a whole 3 minutes with that 12/20, and it SUCKED!! Pulled my ski up on the stand at the edge of the water and swapped pumps back out. It worked out good, because someone at the ride was in need of a SJ pump, so I hooked them up with the spare. Glad I'd brought my main pump with to put back on.
Thanks for all of the input guys. I appreciate it.