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  1. #1
    tmarsh's Avatar
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    Impeller suggestion?

    Decided on winter mods for my RXT, need to choose a prop that will work best for both acceleration and top speed, and what would my RPMs and top speed look like?

    I have already added VTS, but will be adding-
    X charger
    42s
    4" intake
    XS Intercooler
    candoo gps

    Thanks for the help.


  2. #2
    boost junkie skidoochris's Avatar
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    15/20....8000

  3. #3
    tmarsh's Avatar
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    Quote Originally Posted by skidoochris View Post
    15/20....8000
    Thanks for the reply. Ill go with a 15/20. But what would be the performance difference between a 14/19 and 15/20? I don't quite understand yet what effect different pitches have

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  5. #4
    quiddo15's Avatar
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    With the 14-19 you will be all over the limiter, 15-20 has a steeper pitch which will keep u under, your setup has been trialled by 100's of forum members with great results with Srx15-20

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  7. #5
    boost junkie skidoochris's Avatar
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    cold Michigan water/air is going to make those 42s very lean
    most have never ridden in cold water.....
    as long as the ecu is stock it will work
    keep your eyes open for a X ride plate, because you will need it someday

  8. #6
    tmarsh's Avatar
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    Quote Originally Posted by skidoochris View Post
    cold Michigan water/air is going to make those 42s very lean
    most have never ridden in cold water.....
    as long as the ecu is stock it will work
    keep your eyes open for a X ride plate, because you will need it someday
    So is there something I should change to not be lean? I'm not doing anything with the ECU right now.
    i usually don't ride in air temperatures less than 70, and yes the average lake temp up north where I keep the ski docked usually is 72. The lake at home is around 82 and I always loose rpm at home

  9. #7
    Moderator Snoman's Avatar
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    Quote Originally Posted by tmarsh View Post
    Quote Originally Posted by skidoochris View Post
    cold Michigan water/air is going to make those 42s very lean
    most have never ridden in cold water.....
    as long as the ecu is stock it will work
    keep your eyes open for a X ride plate, because you will need it someday
    So is there something I should change to not be lean? I'm not doing anything with the ECU right now.
    i usually don't ride in air temperatures less than 70, and yes the average lake temp up north where I keep the ski docked usually is 72. The lake at home is around 82 and I always loose rpm at home
    You will want to add an Air fuel ratio guage along with a Rising rate fuel pressure regulator...The regulator will be used to adjust fuel accordingly to what your air fuel ratios are which you will be able to guage with the AfR guage i recommended getting

    Quote Originally Posted by gti 130 wow View Post
    Every impeller is a compromise .
    Except for certain progressive type props that to a limited degree , its either top speed or neck snapping torque and acceleration.
    I can give two examples although I don't know for sure how they relate to PWC operation .
    1: To bump up top speed from 43 to 50 , I over propped my 18' foot bow rider and got to 50 .
    One day I decided to take 4 adults with me and found I could not get the boat
    up on top of the water so we just drove around a 5 mph all day.
    2: This 2nd one may be more relevant . In the late 70es my friend had a Kawasaki 100cc enduro motor bike with a 2 speed differential .
    The first setting was for the street and the bike could go highway speeds .
    The 2nd was for off road and it was geared such that it hit the rev limiter around 35mph.
    The off road gearing that to a boat would be like under propping , gave him acceleration and performance up to the 35 mph limit much closer to the single geared 250 cc bikes.
    So if your willing to give up 5 mph of top speed for example that you might only use only on rare occasions , then you can trade that top end performance for performance at speeds that you may spend more then 95 % of the time running.
    OK,SO which prop do you recommend for him???

  10. #8
    boost junkie skidoochris's Avatar
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    every ski is different
    temps, altitude, mods, fuel, rpm all come into play
    the stock ecu on a x charger keeps the timing very low at WOT
    that keeps the rpms/ power down so bigger injectors are not needed
    the seimens ecu @ 11psi cuts the timing to 1/2 of what a X ecu runs



    1800hpa = 11psi

  11. #9
    tmarsh's Avatar
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    Thanks snoman, will do. I do have an LC-2 afr gauge installed already. Forgot to mention that.

    I'll start with a 15/20 and go from there.

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  13. #10

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    Not to change the subject but i assume the exaust valves have already ben replaced ??? The 06 was the mid year that sea doo upgraded the exaust valves so b sure to check the numbers if not already replaced. the number 75 valves are the good ones and the 72 are the bad ones. Just dont want to c u get the ski running good and then drop a valve.

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