Results 1 to 5 of 5
  1. #1
    I'm all out of favors!!
    Join Date
    Apr 2008
    Location
    Orlando
    Posts
    48

    GUTTING h2oBOX??

    So I think I'm thinking too much into it?? But any help for the DIY's like me would be appreciated. Since I can't make or buy an equal length exhaust manifold, is there any scavenge effect now that I've hacked my waterbox? Seems that the moon shape opening on the vertical divider (inside the waterbox) is bigger in area than one or almost two exhaust ports, does there or is there any scavenge effect that far down the exhaust? or am I thinking too much??? I figure since it's a three cylinder, with an unequal length manifold there probably isn't that much exhaust scavenge, but before I take the divider out or trim it to the total area of all three exhaust ports maybe someone else that's better in the math department could help. I'm not building an all-out 100mph boat, but a bouy boat so I figure a 'lil back pressure would be desired? and I don't want to fill a cylinder with water in case the event of "rider ejection" happens (Riva rear exhaust soon). So any help??? And thanks to all for reading the post ( All smart ass comments will be taken in stride).


  2. #2
    R88ory RXP's Avatar
    Join Date
    Feb 2008
    Location
    Kent, England
    Posts
    2,737
    +1
    46
    I think you mite be thinking to much, like you sed. The thing with our engines is that they are charged so the exhaust works in a different way. N/A engines require backpressure to produce there best power. Where as charged engines don't. So really you want to make the exhaust as free flow as possible. I have gutted completly and shortened my waterbox by about 5 inches. This has given me loads of bottom end and it sounds amazing with the thru hull. Mayb a little loud for some peple but i love mine. I dont think that any1 has made an equal length manifold not sure if ther would be big gains to have or not. Mayb some1 hu knos more on this subject will chime in. Hope this helps R88

  3. #3
    R88ory RXP's Avatar
    Join Date
    Feb 2008
    Location
    Kent, England
    Posts
    2,737
    +1
    46
    1 more thing with the riva thru hull the pipe comes up well above the waterline so the risk of water getting back up to the cylinders is almost impossible. I think you will be fine but i would completly gut the box dont leave anything in there and cut the J pipe back by 1 3/4 inches and the outlet pipe up as far as you can. R88

  4. #4
    I'm all out of favors!!
    Join Date
    Apr 2008
    Location
    Orlando
    Posts
    48

    Thanks!!!

    Thanks for the reply, I told myself I'd never go 4 stroke but time and HP changes everthing. I think I'll gut 'er completely, trim the outlet flush with the inside if the water box, and cut J pipe as you suggest. I think @ 5 inches is right around where I hacked it to so I'lll weld it short too. As for the sound, only the guys behind me will have to worry about it . Thanks again.

  5. #5
    R88ory RXP's Avatar
    Join Date
    Feb 2008
    Location
    Kent, England
    Posts
    2,737
    +1
    46
    Quote Originally Posted by sonny//414\\ View Post
    Thanks for the reply, I told myself I'd never go 4 stroke but time and HP changes everthing. I think I'll gut 'er completely, trim the outlet flush with the inside if the water box, and cut J pipe as you suggest. I think @ 5 inches is right around where I hacked it to so I'lll weld it short too. As for the sound, only the guys behind me will have to worry about it . Thanks again.
    lol yep i jus looked at mine i have about 2-3 inches from the back of the j pipe inlet to the back of my box. i does sound amazing pops and bangs when u leave the water, turns everybodys head that is 4 sure. Have fun R88

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. gut the intake mod
    By mongo in forum 4-Tec Performance
    Replies: 0
    Last Post: 07-30-2007, 09:18 AM
  2. Balls or Guts
    By RX951 in forum Open Discussion
    Replies: 8
    Last Post: 01-20-2007, 10:16 AM
  3. Gutting air box?
    By bossdukes in forum 4-Tec Performance
    Replies: 2
    Last Post: 01-14-2007, 08:23 PM
  4. Gutting the waterbox
    By precisionrxp in forum 4-Tec Performance
    Replies: 68
    Last Post: 11-06-2006, 08:01 AM
  5. gutting
    By TxVirageTx in forum Polaris PWC Performance
    Replies: 7
    Last Post: 08-24-2006, 06:26 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •