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  1. #1
    VXRPete's Avatar
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    VXR Mods disappointment

    I have a 2013 VXR and have modded it up based on my research and advice given on this forum (and for that I am very grateful).

    I have done the ribbon delete, Riva air intake kit, RnD intake grate, RnD pump seal kit, Jim's Cut, and Tommy Jordan exhaust mod.

    Not sure if I did the TJ exhaust correctly since I couldn't find install info on VXR. I just removed that plastic resonator add on thingy and plugged the hole with an abs insert and threaded plug.

    Anyway, my dreameter once showed 76 mph and stock I would hit 68 mph on GPS. With my mods all I can get is 66 mph. The machine definitely feels slower. The conditions were calm water evening, temp 25 degrees C. Conditions were about the same during stock runs.

    My machine porpoises a little and never is stable at top end. They say to add a shim at the rear to stop this, but according to Jim when I called he said adding shims slows you down.

    Anyway, any insight would be much appreciated.

    Lunch bag let down isn't pleasant....

  2. #2
    Click avatar for tech links/info K447's Avatar
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    Put the stock intake grate back and see how it affects top speed.

    Porpoising affects speed, so if you need to add shims at the rear of the ride plate to allow the hull to stabilize at speed, then you need to add shims.

    Do these two changes separately as each can affect the other. Then try them together.

    Is the engine peak sustained RPM the same in your before and after tests?

  3. #3
    VXRPete's Avatar
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    I don't know what my top end stock RPM was or modded top RPM is.

    I do know that my idle rpm increased by 150-200 after the mods.

    I will try the stock grate again.

  4. #4

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    on the exhaust mod did you trim about 3 inches off the exhaust hose end that extends down inside the plastic box and remove the rubber flap fingers where the exhaust exits the hull. also you need to get a EXACT reading on the rpms, you might be on the rev limiter if your rpms are getting close to it.

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  6. #5
    Definitely on the rev limiter.Dont run the stock grate unless you want to go for a swim IMO

  7. #6
    VXRPete's Avatar
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    I didn't trim the 3 inch pipe or take the exhaust fingers out. I found your post regarding removing the 3 inch pipe. To remove the exhaust flap, do I uncouple the exhaust at the hull exit to get at it? I haven't examined it there as of yet.


    What is the max RPM I should be running on the 2013? I have no idea what the optimal rpm is supposed to be and where the Rev limiter kicks in.

    If I put the stock grate back on, the Rev limiter will kick in?

    Sorry guys for being a little clueless (...okay alot clueless) on this stuff. I am a snowmachine mod guy and PWC mods are new to me. I have just been bolting on mental horrsepower and not seeing results. There seems to be alot to be done in order to gain a couple of mph vs on a snowmachine that's for sure!


  8. #7

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    no need to remove the exit pipe where it goes out the hull, just remove the ride plate and use a sharp blade to trim the flap fingers off. Also if your vxr has the rubber curtain around pump leave it off also. you must remove the pipe from the water box to the plastic sound suppressor to trim the section of that hose off that goes in to the suppressor box. I am not sure where the rev limiter kicks in on a vxr I know on a stock fzr it starts at 7750 rpms , maybe some one will post exactly where the rev limiter is on a vxr

  9. #8
    Work Harder, Millions on Wellfare Depend On Us! ultramaxracing05's Avatar
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    Probably need to pitch that impeller a bit.

    You also need a tachometer to see where your rpms are at.

    And this might sound silly but even if the ski is running perfectly fine, a set of year old spark plugs will not help the situation.

    I recommend and do spark plugs changes every spring. They just go bad sitting in that wet environment due to the humidity of the waterbox.

  10. #9
    You didn't mention anything about putting a tune on her, thats the only way to really wake her up and get her above the speed limiter of 69. The faster your prop spins the faster your dreamometer shows... Also, dont believe your dreamometer (speedometer), download a GPS app on your phone, thats the only way to measure speed.

  11. #10
    VXRPete's Avatar
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    I haven't mentioned a Tune because I just wanted to stay with regular gas (I'm cheap). After riding with buddy on the weekend who has a GP1800 all Riva'd out, I may have to reconsider. I think he was bored riding with me because I lagged so far behind. Prior to him getting his GP he had a Kawi 310. When I was bone stock he would slightly creep ahead so he got rid of it and went with the GP. I modded up what I could and went backwards and fell off the scale. I use my phone as GPS.

    I will look into spark plugs...is there a certain kind that is better than the other? For example on my turbo 4 stroke sled and other modified sleds I run a hotter plug for increased performance (so the gurus would say). If not, I will just buy the stock plugs.

    I will take the ride plate off and trim the rubber and add a washer in the rear per side of plate. I will also trim the 3 in peice off in the exhaust.

    Hopefully, I can get closer to see what the issue is. For now I will just have to eyeball the rpm.

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