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  1. #1

    Join Date
    Sep 2007
    Location
    Lexington, Ky
    Posts
    1,656

    Assistance on pump choice - High HP XR1800 project

    I recently purchased a mistreated Yamaha xr1800 for a fairly decent price, so I'm left with some money to put into it. I'm looking at about a 6-7k budget, and will be doing most all the work myself. Now that I have it cleaned up, its time to power it up.

    Its a dual engine setup, and I currently have twin 1200 non-pv engines, but plan to upgrade to (2) sea-doo 4-tec 215hp's or (2) Yamaha 160HO's and boost them? I'm looking for 450-500hp total. Not sure which direction I'm going to go in for the engines yet, but want to go ahead and start with the best pump setup I can get for it. Ive been looking for info on the different jet/pump units, and cant find much technical info on flow rates etc...

    However I'm going to worry about engine selection second, I may build up what I have. But I have to put entire new pumps /nozzles on this thing anyway, and might as well go big. I need something that is BIG flow for BIG speed high HP application, and has decent amount of trim. OR can I add a high end aftermarket nozzle with trim? Because in order to get the nose of this boat out of the water I'm going to need some serious trim.... I'm getting a set of trim tabs for it as well.

    I was considering the following?

    Upgrading to an 05-07 1200gpr pump,
    Upgrading to an 07-08 FX 160 HO pump
    Or maybe even an RXP pump

    Does anyone have any data on which pumps flow how much water in comparison to each other, rated PSI levels etc..? I may even be willing to swap to an rxp pump setup if the flow improvement is substantial enough. I have searched but have been unable to find any information on this?

    So let me know what pumps you guys think I should go with? Whats going to get me the best perforance when I add big power? Any and all advice is appreciated thanks!


  2. #2
    First the xr1800 came with 1200pv motors so unless you or the previous owner swapped them out you have 1200pv motors...You can have them bored and ported...Mill the heads to 150psi or higher upgrade to vf2's or vf3 reed cage assembly change out the cdi unit and add tripple pipes to both motors and probably have as much HP as the seadoo motors...Unless you are a REAL good wrench and have a great fabrication man and more than 6-7k if the seadoo motors will even fit(I highly doubt it) I would call lowell horning and send him those motors and have him build you a couple of monsters...As far as pumps go Carl at island racing would be the man to talk to he has an xr1800 jetboat and knows his stuff when it comes to modding these motors...Also yamahajetboaters.com might be a better group to talk to when it comes to modding a jetboat because this is a PWC community...hope this helps...google island racing or lowell horning to get websites and phone #'s...

  3. #3

    Join Date
    Sep 2007
    Location
    Lexington, Ky
    Posts
    1,656

    Thanks.

    Duplicate post

  4. #4

    Join Date
    Sep 2007
    Location
    Lexington, Ky
    Posts
    1,656

    Thanks.

    Thanks for the info. Of course,you are correct, the engines in the boat are power valve motors. I was just confused when the heads were marked 68y,not 66v like I was looking for. Does anyone know what the difference is? Ive decided for now, I'm just going to just work on getting the 1200 motors I have running properly, possibly add some basic power adders, and focus on pump work before I go crazy on an engine swap or something(Maybe that will keep me busy until I can get some of those supercharged 1800's out of the new FX SHO . I have a tendency to get ahead of myself on these projects. Thanks again.

    Some good places I have found for mods Yamaha jet boats are, as you mentioned.

    Yamaha JetBoaters
    Island Racing

    As well as

    GroupK.com
    Atlanticjetsports.com

  5. #5
    African-American
    Join Date
    Feb 2007
    Location
    Cape Town, South Africa
    Posts
    2,226
    +1
    88
    please keep us posted, your project sounds exciting.

  6. #6

  7. #7
    I believe the 05' GPR pump and the FXHO pumps are one in the same. I would go with that pump as it should bolt right up along with dynafly 14/20 props and have them pitched according to your motors. Like was said, send the motors to Lowell, have them bored and ported. See if triple pipes will fit in and let it rip!

  8. #8

    Join Date
    Sep 2007
    Location
    Lexington, Ky
    Posts
    1,656

    Update on project

    Well, I've lost my mind... Bought 2 4tec motors for this thing... Good thing I did, because when I went to sell the 1200pv's in it, turns out one of them had lost compression in one cyl, so I was looking at rebuilding the other motor anyhow. This is gonna be one FUN project!! I'll keep you updated with Pics once I get somewhere with it. Oh yeah, I have (2) 05+ yami pumps ready to go on this thing as well!!
    Last edited by boostaholic; 11-02-2007 at 03:10 PM.

  9. #9
    I think you just bought yourself a huge headache trying to get those 4tec motors to fit. Personally, I would send those 1200 cylinders off to Lowell and have them bored and ported as well as have him do the head for premium pump gas. Then add a keyway or Advent igniton and that thing will rip.

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