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  1. #31
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by sdlvx View Post
    ... GP 1800 is speed limited by the computer. ... 4-stroke having a narrower power-band ...

    So you'd be about equal in weight, GP 1800 has 180hp and GP 1800 SVHO has 250, right?

    ... I don't think this could be answered very easily, but I'm 2-stroke biased. ... Probably not many though ...
    Have you ridden a recent year top-model supercharged 4-stroke PWC?

    They are typically not ‘a little quicker’ in acceleration than most quick 2-strokes, more often a lot quicker. Mid-range acceleration is just silly. Especially when tuned with mild hardware upgrades.

    The factory Yamaha SVHO engine is rated circa 250HP IIRC (Yamaha puts 184KW on the engine label), but the actual stock engine output might be closer to 270-280. There is a factory speed limiter at circa 69mph GPS, same as most every other ‘very fast’ supercharged PWC.

    A Riva MaptunerX ECU tune to Stage 1 raises the engine power output, RPM limit and removes all the speed, boost and power limiters. I have the Riva Stage 1 Plus 91 octane tune for my GP1800 SVHO, so something circa 300hp, probably a bit more.

    Depending on the tune, fuel octane and the hull configuration - top speed, GPS measured, the GP1800 SVHO is somewhere just shy of 80mph, sometimes a little more. I typically run the Riva 91 octane tune and the hull is more set of for rough water handing rather than speed. 75mph still happens regularly.

    Among friends we ride with from the Polaris PWC world, we do let them test ride our Yamaha. Several have now purchased GP1800 SVHO of their own. And some have now sold all or most of their Polaris PWC.

    The most recent annual Polaris and Friends PWC gathering on Harsen’s Island looked like this

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  3. #32
    MSX 150 guy lives on Mr. GP1800's Avatar
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    I’m sorry but I’ve either owned or ridden almost every Polaris ever made. I own a matrix. None of them are even close to the ride, handling, and power of my GP 1800. No 2 stroke would ever come close unless it was 1800cc. The 4 stroke motor is so smooth and can be ridden comfortable at any engine rpm without it shaking the piss out of the machine and rider. No way Polaris would invest the resources needed to compete with what’s out there now for skis

  4. #33
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    I'm just saying some people like that violent ride. There's faster things than a Pro 785 out there, but I love them because they are violent, loud, mean, they feel like they want to hurt you when you ride them. 4 strokes are smoother, but I miss having the pipes hit hard. I think there's still a market for that.

    The Polaris ride doesn't surprise me though, Polaris skis were 15 years old, at best, in 2019 and a lot has happened with PWC in those years. I did assume that the triple pipes could make up for displacement, they do for a pro 785 compared to a pro 1200.

    I'm probably not a very big part of the PWC market. I spend most of my time on standups and when I hop on a Pro 785, it feels like a very big boat. MSX and 4 strokes feel like barges to me.

  5. #34
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by sdlvx View Post
    ... violent ... having the pipes hit hard.

    ... I spend most of my time on standups ... Pro 785 ... feels like a very big boat.
    MSX and 4 strokes feel like barges to me.
    Imagine having that sort of acceleration throughout the hull speed and RPM range.
    Several friends who have ridden our GP1800 come back after their first ride asking ‘How is this much power even legal?’

    I used to ride Polaris SL size watercraft fairly often. SL650, SL900 (eventually put a 1200 in that), and friends with various SL and Polaris Pro 785 and Pro 1200 iterations. Quick and fun for while, but so often the lakes and rivers are chewed up with boat wash, wind chop, and so on. Flat water happens but not that often. The short 2 seater hulls are fatiguing on longer rides, which is the majority of our use. Cruise range on a full tank was OK but not amazing.

    We had Virage 1200 and MSX 1200 models for years. Not as abusive a ride as the 2 seaters but the Yamahas we ride now are much, much better. Moderately rough water is now smoothed out by going faster. The jet pump stays hooked up way better than my Virage ever could, and better than the MSX too.

    Also a lot less noise. A while back I was helping a friend with Genesis i. At one point I took the seat off and did a test ride. The clattering racket from the engine was ridiculous, yet the engine was operating normally. I had just forgotten how much sound a big 2-stroke engine makes. With the seat on it is still a lot noisier than my 4-stroke Yamaha. We used to always turn our Polaris engines off in order to talk to each other. With the Yamaha I can idle and converse in a normal voice.

    I consider the current Yamaha VXR and GP1800 to be a logical modern transition for people that liked the Polaris MSX and similar models.

    The Yamaha EXR matches up fairly well with the feel of the Polaris 2 seater models.


    Seadoo has gone in different directions. We have friends with Sparks and they are quite bouncy in anything that is not smooth water. Quick enough with an aftermarket tune, but not a hull I want to spend much time on.

  6. #35
    MSX 150 guy lives on Mr. GP1800's Avatar
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    Yamaha EX models are almost the exact size weight and horsepower of a Polaris SLTX. The EXR is lighter and around 125HP. I think he EX models are 100HP. The sltx I believe areas around 120HP

    climb aboard a Yamaha model with ride and you’ll wonder how you ever lived without it.

  7. #36
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by Mr. GP1800 View Post
    Yamaha ... EXR ... around 125HP.

    ... EX models are 100HP. ...
    EXR stock weight is 540 pounds dry with 110HP, 10% more hp than the 100hp in the 600 pound EX.

    Aftermarket tune kit with impeller upgrade further boosts the EXR engine power, acceleration and top speed numbers.

    1997 SLTX, for comparison, is 615 pounds dry weight.
    The very fun SL1050 and SL900 were both 520 pounds.

  8. #37
    Quote Originally Posted by Mr. GP1800 View Post
    Yamaha EX models are almost the exact size weight and horsepower of a Polaris SLTX. The EXR is lighter and around 125HP. I think he EX models are 100HP. The sltx I believe areas around 120HP

    climb aboard a Yamaha model with ride and you’ll wonder how you ever lived without it.
    I’ll race any EX, EXR or Spark on my 2002 seadoo XP, which is 130hp stock. You can now get one for ~$1500. Its goes 62mph gps. Why would anyone drop $9k on a new and 10 mph slower ski. More complicated, more expensive AND slower?

  9. #38
    Quote Originally Posted by K447 View Post
    I would expect similar power to the previous Matrix motor, maybe a bit more. The tuned triple exhaust pipes act like a turbocharger (but without intercooling) thereby packing more air density into the combustion chamber than atmospheric. That extra air plus fuel mixture to match would produce a little over 200hp, maybe 220hp? ...

    To get a lot more power the 1200 engine would need (quite a bit) more displacement, or (a lot) more RPM, or something to compress even more air into the combustion chamber (like a turbo?).

    More RPM is possible, but expensive/light weight parts needed. And the tuned pipes would need to be (re)tuned for the higher RPM level.

    The 4-stroke supercharged Yamaha SVHO engines is 1.8 liters and boosted (and intercooled) to about 2 Bar, so roughly twice atmospheric air density is being pushed into the intake manifold. That SVHO engine produces about 300hp with a basic aftermarket ECU tune.

    To get the 2-stroke engine with similar power is going to require a lot more of something. Cost, displacement, complexity ... all three?
    Don’t forget a lower price point sells skis. The Spark clearly proved this. Any 1800 is a price step up category for sure. Its way on the high end price wise. $15-$18k. Two cycle engines will always be cheaper to make. There are simply less parts.

    In 2004 Polaris put exhaust power valve cylinders on 800 sleds. Neither the MSX 140 or the matrix builds had them on the 1200. The 800 powervalve cylinders bolt right on the 1200 crankcase. Sled guys were making hybrid 1200 race motors at the time 250-285 HP no problem. A factory production version of this motor could make 250 HP no problem. Especially if equipped with a newer DFI system. If it was end user programmable that would be gold!


    No oil to change

    No supercharger to fail.
    (The reason I won’t buy a SVHO ever! Six 1800s in my area all with supercharger fails at 100 hours.) 80%

    No “dipstick was left out by dealer and oil is gone”. Distress call.
    (I got a call by stranded person 38 miles off the southern Coast of AK last weekend with this exact scenario)

    If ski is swamped your engine is not destroyed. A guy washed up on my neighbors dock with 20 year old ski 2 weeks ago. Ski full of water... Drained water, changed spark plugs and he rode home.

    2-strokes won’t be in the “too expensive to fix” junk yard in 10 years. Much greener technology. Find a 2004-2010 Seadoo worth repairing.. It costs twice what they are worth.

    I’m not sure if technology is taking us forward or backward.. now that I think about it.

  10. #39
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by Mentzel View Post
    ... lower price point sells skis.
    ... Any 1800 is a price step up category for sure...

    Two cycle engines will always be cheaper to make
    . ...

    ...

    No oil to change
    Oil changes are less hassle than maintaining oil level in the 2-stroke tank. Most seasonal watercraft go the entire riding season without changing oil. Done as part of the dealer winterizing process.

    During the riding season, the owner just refuels with gasoline, not a thought given about the 4-stroke oil.

    We all know of 2-stroke engines that failed due to oil starvation.
    And it doesn’t take long. Ride them for a week on vacation without adding oil, the 2-stroke oil tank will be empty and the engine will be hurt


    No supercharger to fail.
    Plenty of fun 4-stroke models without supercharger.
    The ‘big’ non-supercharged engines develop 150 to 180hp, depending on the brand. The smaller engines 90-110.

    One of my own GP1800 went 222 hours before the first supercharger clutch needed changing. I was not stranded, merely limited to about 50mph. We could have rode it hundreds more miles to get home if necessary. The other machine is still on the original supercharger clutch at nearly 300 hours. For many owners, 200 hours is maybe a decade of riding.



    No “dipstick was left out by dealer and oil is gone”. Distress call.
    Incorrect or incompetent service can disable or damage any engine type. Hose clamp loose, whatever.
    That is in addition to people forgetting to refill the continually disappearing 2-stroke oil tank.



    If ski is swamped your engine is not destroyed.
    Plenty of 4-stroke PWC recover from engine flooding. It takes more work and involves multiple oil changes, but entirely doable.


    2-strokes won’t be in the “too expensive to fix” ... in 10 years. ... Find a 2004-2010 Seadoo worth repairing...
    2004 was the very beginning of the 4-stroke PWC era. Of course the first generation machines have depreciated a lot.

    A 2004 Polaris needing a full engine rebuild (and everything else that probably needs doing) today costs way more to repair than it is ‘worth’.
    When they were ten years old it was close to even money whether it was financially ‘sensible’ to do a full rebuild, more so if a shop was being paid to do the work.

    ...
    2-stroke engines in PWC are not going to come back, not for an emissions compliant, cost of ownership reasonable, broadly appealing watercraft.

    The small 4-stroke engines are close enough in total product costs (vs a putative ‘modern‘ 2-stroke PWC) and the product longevity is much, much better.

    The ‘excess’ weight of the newer 4-stroke engines is no longer a big delta overall. Yamaha is going to sell a bunch of the new 4-stroke SuperJet stand-up and the buyers are going to be happy with them. Many of those buyers are going to come from 2-strokes and know what they are leaving behind.

    I like the quieter and less frenetic 4-stroke exhaust, and the lack of exhaust smell. My own fuel injected 2-strokes engines did not smoke much at all, but they did clatter at slow speeds and wail when going fast.

    If I was lucky I would get 200 running hours from a 2-stroke PWC engine, and usually much less. Since I had several PWC, it seemed like I was rebuilding an engine if not two almost every summer.

    I have not rebuilt or even worn out a 4-stroke engine in the four years since I bought them. And my expectation is that those engines will carry on for years more.

    If I had bought two brand new 2-strokes four years ago (if that was a thing that was possible) by 300 running hours I expect one or both would be nearing or already had to be rebuilt. The ongoing cost and hassle of multiple engine rebuilds over a decade of ownership is enough to keep me away from 2-stroke engines in new watercraft.

    Even within the racing world, PWC racers are recognizing that the long term future is not 2-stroke. Certainly not the carburetor 2-strokes that were current/old technology decades ago.

    And probably not any form of fuel injected 2-stroke. BRP was the last company actively selling a fuel injected 2-stroke marine engine (Evinrude outboard) and they just announced the end of that.


  11. #40
    MSX 150 guy lives on Mr. GP1800's Avatar
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    Quote Originally Posted by Mentzel View Post
    I’ll race any EX, EXR or Spark on my 2002 seadoo XP, which is 130hp stock. You can now get one for ~$1500. Its goes 62mph gps. Why would anyone drop $9k on a new and 10 mph slower ski. More complicated, more expensive AND slower?

    Because your sea Doo 951 Will blow up every 30 hours While the ex just keeps going and going and going

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