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Seadoo rxx pump outlet ring sizes?

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Two 96 Polaris 1050 slt’s a seadoo Rx 951 and a seadoo rxx 951 race. Also have a Polaris 785
#1
So I have a pretty nice condition rxx that Ive been working on lately to try to get as much out of it as I can. Used to be the fastest one around but my buddy just bought a Yamaha four stroke and he is whooping me lol. I doubt I’ll be able to ever beat him but it would be nice to at least keep up lol. I read you can change out the ring on the outlet nozzle of the pump and make it go faster? Is this true? Anyone know the inside diameter that would be fastest. I don’t care about acceleration much just all out top speed. I own/run a boat shop and in it is a full machine shop so I’m thinking I can pretty easily make my own rings in whatever diameter I need that works the best. On it right now there is a “83” so I’m guessing (haven’t measured yet) that it means it has a 83mm inside diameter. Can anyone shed some light on this topic or anything else to make it faster for me? Thanks. Ian
 


Matt Braley

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#2
There is not a whole lot to gain there maybe a mph or two. larger rings in the reduction nozzle are for a faster take off "holeshot" and the smaller one is better for top speed. Too small and you run out of power so you are overloading the engine. 82mm is about as small as I've seen them use on there.
 
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Two 96 Polaris 1050 slt’s a seadoo Rx 951 and a seadoo rxx 951 race. Also have a Polaris 785
#3
There is not a whole lot to gain there maybe a mph or two. larger rings in the reduction nozzle are for a faster take off "holeshot" and the smaller one is better for top speed. Too small and you run out of power so you are overloading the engine. 82mm is about as small as I've seen them use on there.
Is that on an rx or the rxx race ? Thanks.
 

Matt Braley

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#4
The RX nozzles are just cast and do not have interchangeable rings unless someone has replaced them. The RXX nozzles are made by Skat Trak and accept the billet rings.
 
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#5
My experience with rings is there's not a lot to gain but in a pro race it might be the edge you need for that 1/10 sec. The ring installed on my Berkeley ruined reverse completely so I took it off and behold the only difference was a vastly better reverse.

So this Yamahaha, 300+hp?
 
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Two 96 Polaris 1050 slt’s a seadoo Rx 951 and a seadoo rxx 951 race. Also have a Polaris 785
#6
My experience with rings is there's not a lot to gain but in a pro race it might be the edge you need for that 1/10 sec. The ring installed on my Berkeley ruined reverse completely so I took it off and behold the only difference was a vastly better reverse.

So this Yamahaha, 300+hp?

No. It’s a older sho. So he shouldn’t have me by much I wouldn’t think. It’s all stock so I’m guessing it’s right around 70 mph. The guy my buddy bought it from claimed 72 but I’m not sure I believe him lol. It’s def fast.
This rxx doesn’t have reverse. So no worries there. anyone have any other ideas to get more out of the old girl? I’m up for anything. Hull mods. Pump mods (I’m betting scat track had that covered to the max). Engine mods. Ride plate mods. Water box delete. I don’t care what it is. I’m up for it. Not looking to build a bigger more unreliable motor though. Thanks for the help guys. Ian
 

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#7
Nope you are already maxed out. Seadoo threw everything they had at it to make it the fastest ski at the time. There’s really no where else to go unless you want to get into porting, high compression heads and race gas. Even then the very short engine life of an RXX will get even shorter.
 
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Two 96 Polaris 1050 slt’s a seadoo Rx 951 and a seadoo rxx 951 race. Also have a Polaris 785
#8
So what should be my top rpm and mph? I’ve read anywhere from 6800 to 7200 and just about 70. Sound right? Thanks
 

Matt Braley

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I can't keep up with it anymore. I've got some really cool skis!!
#9
No you will not see 70 GPS from an RXX. 65-66 maybe if your under 200lbs with the wind at your back and everything else is just right. 64ish for me at 225 in the FL heat.
 
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Two 96 Polaris 1050 slt’s a seadoo Rx 951 and a seadoo rxx 951 race. Also have a Polaris 785
#10
Nope you are already maxed out. Seadoo threw everything they had at it to make it the fastest ski at the time. There’s really no where else to go unless you want to get into porting, high compression heads and race gas. Even then the very short engine life of an RXX will get even shorter.
I feel like there might be some minor hull mods that will help out top end. Pretty much all manufacturers radius the edges of everything on fiberglass boats/skis to make removal from molds easier. I noticed the other day thst all the edges on the rxx have about a 1/2” radius on them. I’m gonna add some black epoxy to the edges to get them razor sharp. I bet it’s worth at least a mph. The drag that a round edge creates is pretty substantial. We’ll see though. Was also wondering if a little more hull length would help. Maybe a longer ride plate too. Even the ride plate has a very round edge. I would think I could help that area out as well. Thanks for the info guys. Ian
 

Matt Braley

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I can't keep up with it anymore. I've got some really cool skis!!
#11
You can get a ride plate from a 97XP and it will give you a mph or two.

There is also a little top speed potential with a plastic 155mm pump that has no damage with a Solas 15/20 Concord impeller in it. This will actually accelerate slower then the Skat Trak pump and nozzle setup that is on the RXX now but have a little more top speed.
 
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Two 96 Polaris 1050 slt’s a seadoo Rx 951 and a seadoo rxx 951 race. Also have a Polaris 785
#12
You can get a ride plate from a 97XP and it will give you a mph or two.

There is also a little top speed potential with a plastic 155mm pump that has no damage with a Solas 15/20 Concord impeller in it. This will actually accelerate slower then the Skat Trak pump and nozzle setup that is on the RXX now but have a little more top speed.
I e got another straight up “rx” any of the parts from that work? It actually has a pump from and earlier model cup that I had to install cause the pump split from sitting. So now that one is parts for the rxx. I actually think I’m gonna have to stick the single pipe on it for a bit. The twin pipes on the rxx are leaking on the outside. So I’m gonna have to pres tear them and fix the bad spots. Thanks for the info. Anything else is appreciated. Thanks
 

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