How to read impeller numbers: ie: 13-19 vs 14-18

[rjcress]

I've tried a few searches and haven't found this explained, although I'm sure it has already been answered over and over.

My wear ring is chewed up and the impeller dinged on my 2000 GTX DI. Looks like my brother-in-law forgot to mention that he ingested something in the jet pump. Yes, I'm as shocked by this as you are.
So, I'm thinking now may be the time to rebuild the jet pump and upgrade to an aftermarket impeller.
In this impeller reference (http://impros.com/charts/skat_seadoo.html) I see a few different specifications listed, but don't understand what they mean or which would be a better fit for my intended use.
The engine is freshly rebuilt by SES with no modifications.
Looks like the stock impeller is 14/21, and the recommend that boats with the stock engine use 13/19 or 14/18 Swirl.
Can someone please point me to info or help me understand what the numbers (14/21 vs 13-19 vs 14-18) mean, so I can sort out whether to:
-get the stock impeller rebuilt
-get a 13/19 impeller
-get a 14/18 swirl impeller

Intended use:
This is for my 2000 GTX DI, which will likely be used for rapid transit between my big boat/marina, and my parent's house, which is a 10 minute ride from my marina. Or solo exploring around the lake. Most of the time it will be with me (195lb) and my wife (I'm not telling, but a good bit less than me), or me and one of my kids (kids are all between 55 - 65lb each). We may occasionally pull a tube or skier.
I am more interested in torque/quick start/rough water start than in top speed.

Thanks!

 

[SabrToothSqrl]

Isn't that ski a 951? The prop of choice for a 951 is a Solas Concord 15/20.

The 13/19 will give you better acceleration. The 14/20 better top end.

Boats,only get one "gear". Choose wisely.

I run the concord 15/20 in all my 951 skis.

The concord actually beats the stock prop in acceleration and top speed. The blades are a bit thinner, polished and I think it's even cheaper than OEM.



http://impros.com/store/index.php/tech-info/about-impellers.html

 

[rjcress]

Isn't that ski a 951?

Yes... the DI version of the 951

 

[rjcress]

Isn't that ski a 951? The prop of choice for a 951 is a Solas Concord 15/20.

The 13/19 will give you better acceleration. The 14/20 better top end.

Boats,only get one "gear". Choose wisely.

I run the concord 15/20 in all my 951 skis.

The concord actually beats the stock prop in acceleration and top speed. The blades are a bit thinner, polished and I think it's even cheaper than OEM.

http://impros.com/store/index.php/tech-info/about-impellers.html

I must be over thinking this. I had read that impros.com article, and it has great info, but doesn't directly answer my question... I'm still trying to make sense of the options, of which there are now 5, since the Concord 15/20 has been added. I want to "choose wisely", but still am not sure I understand all of the variables.

So, the first number is the pitch at the leading edge, second number is the pitch at the trailing edge, right?
Am I getting the following right... impellers of the same design, but different numbers might be described compared to the stock 14-21 as follows:
13-19 less leading edge pitch so less "bite" and less friction, so higher RPM. less trailing edge pitch, so less bite and friction, so higher RPM. This should allow a stock engine to get to into the highest output RPM range quicker, making for quicker starts, but will have a lower top speed. Should be more low to mid range acceleration.

14-18 same leading edge pitch, so no impact on RPM, less trailing edge pitch, so higher RPM. This should allow a stock engine to get to into the highest output RPM range quicker, making for quicker starts, but will have a lower top speed? Would this mean more mid range acceleration?

15-20 more leading edge pitch for more bite and less rpm, less trailing edge for less bite and more rpm... I'd guess that this would be about the same, but I know a LOT of variables aren't being considered.

But the descriptions above assume the same design and don't consider the over variable that the different manufacturers and designs have. Other variables:
-rotational mass differences in impellers
-impeller contour and transition from leading to trailing pitch
-leading edge profile (straight, curved... this is what they mean by "swirl", right?)
-surface finish (although impros implies the different finishes don't yield measurable differences.

The more I think about this, the less confident I am in my ability to "choose wisely", as I am pretty new at this and don't understand how all of the variables play off of each other.

I get the Concord 15/20 recommendation SabrToothSqrl... but found a deal on a dynafly for about 60% of the Concord's cost. I'm wondering if I'm completely over thinking this and I'll be ok with any of the above options. I'm not a hard core rider.
And the last consideration is that I'm likely to sell the GTX pretty early in the summer... so I'll only use it a few times. I sort of inherited it when my brother in law broke it and my father didn't want to mess with it. I'm also rebuilding a Challenger jet boat, which I expect I'll keep all summer, as I can fit more kids in the jet boat. So on the GTX impeller, is any choice going to be better ROI for me when I sell it? Put simply, if I spend $200 on a new impeller, am I likely to get any of that back when I sell. The more I look at my stock impeller, the more I am thinking that I can probably file down the nicks in the leading edge and not have to put any $ into a new one. My initial thought was that since I'll have the jet pump apart to change the wear ring, bearings, orings, oil, etc... may as well put in a "better" impeller. Now I'm wondering if it is worth the cost, considering that I'll likely only ride it a dozen times before I sell it.

Thoughts, anyone?

 

[howie099]

Every manufacture is differnet in there pitching so it is hard to say. The carts the aftermarket companies give are very good to go by. The swirl design by Skat is more bottom end, rough water, and chops up veggie real good. Those I have on my jet boat since I like to have a faster hole shot and pulling tube. Most of the other ones give you more top end or mid range.

Personally I like the swirl desgn I would rather give a 1 or 2 MPH to have better hookup and holeshot. I did buy a concord solas impeller for my 95' GTX since the cost was $60 less. I would of liked the swirl but I couldn't see spending $60 more on a ski I pretty much got for free and the OEM one was all beat up.

If you found a DynaFly to 60% less than the Concord that sound like a no brainer to me. That impeller is a newer design go for it. It has to be better than the OEM one. If the bearings are good and the pump doesn't leak I wouldn't take it apart. You sually have to have the bearing pressed in and out of the pump.

 

[SabrToothSqrl]

Your over thinking it. Lol. If it will be for sale soon, go the cheap route.
No one will buy a ski for full price if they can't test ride it... You'll get more $ if they can test it out first

 

[rjcress]

I figured I was over analyzing. I tend to do that.
Just bought a Solas DynaFly Impeller ST-DF-13/19 on Fleabay for $125 shipped.
I probably could have gotten away with filing the dings in the stock impeller, but I wouldn't feel right selling it knowing that it wasn't 100% "right".
Besides, I hope to ride it for at least a few weeks in the spring before I sell it.

Guess I should get started installing the freshly rebuilt motor now.

Thanks again for the input, guys.

 

[SabrToothSqrl]

Good luck. I fix 951 skis exclusively. The GTX is easier than a GSX, but harder than a XP.

Test the starter before you finish. Also, getting that pipe on is an art.

 

[rjcress]

Good luck. I fix 951 skis exclusively. The GTX is easier than a GSX, but harder than a XP.

Test the starter before you finish. Also, getting that pipe on is an art.

Yep, and your SES recommendation is why I sent it to them to rebuild.
Thx for the starter advice.
If you have any tips for getting the pipe in properly, please share.