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  1. #1

    exhaust modification

    well i,ve done it.
    since no one here in australia is doing any r&d on the ultra,s ive tryed a few things for myself.

    today i removed both mufflers & made an exhaust that goes through a u bend & straight out the back.i used stainless steel mandrel bends, urathane couplers,ive injected water from the engine & the factory exhaust manifold into it.the sound is f$#@#$$#ing awsom,very noisy with no water but not so bad with water running through it.took it to the river today and tested it.there were no real gains or losses it still does 68mph on gps and revs to 8010,if any thing it feels a little differant in the midrange i cant check it properly until we hook up an o2 censor next week end.i,m not sure if it can or will cause problems but at least i,m willing to try.there doesnt seem to be any heat issues,i ran it wot for 2km and then played around for another 20 mins till i put it on the trailer.

    oh my mods & conditions are as follows

    pump wedge
    my modded ride plate
    valve cover block offs
    my intake
    my exhaust
    adjusted blow off valve
    oil level checked


    12 deg c
    500 mtrs above sea level
    no chop
    qtr tank of fuel (buzzer just started to go off)
    weight 75k
    sitting on back seat
    fresh water(with lots of debris in it,weve
    had lots of rain)
    next mods hopefully will be computer to try get some more out off it

    Last edited by aussi 250x; 07-14-2007 at 03:32 AM.

  2. #2

    Join Date
    Apr 2007
    Melbourne, FL
    That's great! Good job! What size tubing did you use?

  3. #3
    GOOD Stuff. Lets see some pics

  4. #4
    TurboJimmy's Avatar
    Join Date
    Aug 2006
    Goodlettsville, TN
    Good job. I wish R -Rated would finish their kit soon!

  5. #5

    exhaust mods

    hey guys
    i used two and a half inch mandrels i,ll post some pics next week for all to see i was to keen to see if it worked to take pics as i went sorry but i will try and get some with it all together.

    skip can you see there will be any problems with this mod ?.
    i was surprised that it didnt seem to make any differance other than the awsome noise,it sounds kinda like the turbo sea doo,s only better of course.

  6. #6

    Join Date
    Jan 2007
    I was talking to R-rated yesterday about the stage 2 waterbox and waterbox mods and mentioned I had heard they were doing a no waterbox exhaust. When I mentioned it the person on the phone said it was mainly race only and the risk of getting water in the engine is higher on slight roll overs.(This is how I interpreted the conversation)

    I have not really figured out why it is higher or exactly how the risk differs if the u-bend sits as low as the original waterbox.

    I have thought about doing this myself I would love to see the pictures and hear it.


  7. #7
    i do intend to race our season starts in 4 weeks.the u bend is slightly higher than the original water box but lower than the manifild it may be possible that in a roll over that water may get in but i,m just a rookie trying new things so my opinion doesnt count for much.i dont care much for riding in surf i just want to go fast and sound good.
    i,m working on the pics i,ll try to post later today so you can see what i,ve done and make your own choice from there.

  8. #8
    I see no issue with this mod other then what is stated.

    The water box can act as a holding tank making it hard for back flush to happen. Straight pipe could have an issue with back flushing but dont think it will happen. "opinion"

    With no back pressure on the exhaust you will need to cap off the exhaust ventilators.

    Let us know how it works out. Are you running a EGT or O2 to keep track of your mods?

  9. #9
    exhaust ventilaters ?.
    where and what are they.we are hooking up a 02 sensor this week to check, my dealer has stock readings and will check them against mine.
    i tryed to get some pics but its to hard with the intercooler in the way and i dont feel up to taking it out again,i had it in and out about ten times while fitting the exhaust soory guys you will just have to wait for pics.

  10. #10

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