SXi Pro carving mods?Tubbie Destroyers vs. PW Sponsons?

Jamescmei · Jun 16, 2019

Ok so this is the second SXI Pro I have for my GF. I ride the SXR and I need her to keep up.

She is 130-140lbs with riding gear on.

The first Pro is bone stock other than the plate being shimmed down to help the porpoise. Fun ski to ride and learn on, playful, carves ok but more of a sliding tendency. A dog on the low end.

She rides the stock ski great so “tray time” isn’t really the solution for the porpoise as she can rip pretty good on a stock Pro and control the porpoise.

So I built her this second Pro with an 850 big bore, this Ski definitely has some get up and go. I used a D cut Worx extended ride plate with the double concave shape (like a stock stxr 1200 look) and a worx? (I think) scoop intake grate. This rideplate is long...it is 19.5 inches long! (I don’t know of one longer.) Nozzle has stock shim installed nozzle down/nose down.

With several washers as shims in the back of the plate, I (180 lbs) was able to hammer it and not get a porpoise. The problem was once my gf was on it it seemed waaay too nose low in turns. Even with me on it it seemed I needed to be way back on the ski to keep it from washing out in corners. I pulled all the shims out and it cornered better for her but porpoises worse. I but half the shims back in and she has yet to test ride it. Obviously trying to fine tune the plate.

Now I hear the Pro can really handle well with hull extensions (no longer avail) extended plate and tubbies up front. Now am I correct in assuming I shouldn’t need hull extensions if the plate can get me enough nose down?

Can I shim back in the nose down pressure and correct it with tubbies up front?

What is the best set up to make these things carve?

It seems nose down was porpoising less and cornering worse and vice versa.

I want both, to remove the porpoise and improve the grip in the corners.

Any help would be appreciated!

veedubs · Jun 18, 2019

I had my Pro (now sold) set up with Blowsion Tubbie II’s and Waterdawg Hull extensions. Those two things were the absolute best thing I did to that ski. No porpoising and cornered almost like an SXR. I was also running a TBM SXR ride plate on it but, it handled great with the Stock plate as well. Contact WaterDawg and see if he’ll make you a set of rear extensions. If not, I’d keep the long ride plate you have and install some new style Pro Watercraft Racing front sponsons. I bet that would get you the handling you seek. Also on the Pro’s the double scoop intake grates really help. They are getting hard to find but they pop up for sale occasionally. Hope that helps. I love SXI Pro’s. Very underrated ski.

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Jamescmei · Jun 18, 2019

Awesome, yeah I was hoping with the long ride plate I could skip the hull extensions. If I could get this thing to handle though I’ll do it. Out of curiosity why do you recommend the PWR sponsons over the tubbie II?

Thanks for the input, I’ll hit up Waterdawg and see what they say.

veedubs · Jun 18, 2019

I recommend the Pro Watercraft sponsons for a few reasons. One, they are less aggressive so you don’t need the hull extensions to run them (since they are hard to find). Two, the PWR sponsons are way easier to install. Three, they are a way more modern design and Chris Hagest has put a ton of real world testing on the design to make sure it works. I run them on all my current boats and couldn’t love them more.

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Jamescmei · Jun 18, 2019

I hit up Waterdawg, the extensions are still listed on their webpage as available so we shall see. Thanks, I appreciate the insight.

Jamescmei · Jun 20, 2019

Waterdawg had the hull extensions in stock. They are ordered.

Now I need to decide Prowatercraft sponsons or Tubbie Destroyers.

Jamescmei · Jun 20, 2019

Talked to Pro Watercraft, they recommended the hull extensions, shorter plate, front sponsons, and then removing the factory rear sponsons and installing their rear sponsons. Got caught off guard with the rear sponson surprise. It doesn’t seem like many people run them.

DJAH · Jul 2, 2020

How did u find the hull extensions? Did they work for you jamescmei?

Jamescmei · Jul 3, 2020

Yes, very happy with the extensions coupled with the long Worx rideplate. The plate is the long one, like 20 inches??? I can check for ya.

I’m 180-190lbs and can ride the ski wide open (GroupK 850 Sleeper). The ski as set up can be just on the edge of a porpoise, meaning if my weight is off you can make it porpoise a little but very easy to get under control with a little forward lean. The ski is set up for my much lighter gf so she has no issues. I would think you could shim the plate down more if need be.

This was the only real solid cure for that porpoise we all hate. I have another Pro with just the super long plate, maybe Jet Dynamics?, and it’s shimmed down. That one is better than stock and sufficient for lighter riders to not porpoise, maybe less than 140lbs, but not me.

I also did the Pro Watersports front and rear sponsons and the ski hooks up nice.

My only complaint about the whole package, compared to my SXR800, is that it’s a bit nose low in the turns so you get splashed in the face on a hard carve. The high speed chine walk is better but still there, with proper balance and you can ride it WOT though with practice.

The ski is not as easy to ride as a SXR but with a good rider you can run with an SXR. It may even be faster as it’s lighter (850 Sleeper Pro vs 850 Sleeper SXR). It can hang in the turns but takes more skill/practice to do it.

My gf runs the Pros the most, I run the SXR...she can hang.