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  1. #1

    Question WHICH compression ratio?

    Hi everyone, I'm gonna rebuild my engine soon and must change the pistons so what is the best compression ratio to choose? 8.5:1 or 9.5:1 ??

    I have Seadoo RXP stage 2 with X-modules charger so I'm looking for more power.

    Thanks in advance


  2. #2
    SingTH's Avatar
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    Looking for more power!! more boost ,more parts, more speed and more money.

    8.5:1 for Hi boost

  3. #3
    I'm not looking for more boost, my max boost 12 psi

    when we choose the 9.5:1 CR??

  4. #4
    Moderator Snoman's Avatar
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    IMO if your running that high of boost i would stick with the 8.5 to 1 if you want to stay reliable..But like i said..this is just my opinion

  5. #5
    Got Boost? psycho rxp's Avatar
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    The 9:5 to1's will need race fuel if you run OEM<RIVA<LES COOK ECU setups. They are more for race boats with aftermarket stand alone ignitions, that have full control of ignition timing.

  6. #6
    Quote Originally Posted by psycho rxp View Post
    The 9:5 to1's will need race fuel if you run OEM<RIVA<LES COOK ECU setups. They are more for race boats with aftermarket stand alone ignitions, that have full control of ignition timing.
    I'm already runing 98 of octane's so is that enough for that amount of the compression ratio??

  7. #7
    Quote Originally Posted by Snoman View Post
    IMO if your running that high of boost i would stick with the 8.5 to 1 if you want to stay reliable..But like i said..this is just my opinion
    With 8.5:1 no problems at all but what I'm looking for is more information on the 9.5:1 CR

  8. #8
    Any more information or users?

  9. #9
    Eric Ocman's Avatar
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    Quote Originally Posted by Crazy-doo View Post
    Any more information or users?
    Looks like Jason gave you what you needed bro. Those are more geared for full race boats running race gas and with a more programmable engine management system.

  10. #10
    Got Boost? psycho rxp's Avatar
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    I was gonna buy them for my ski, but was advised against, IF NOT running race fuel, or at least a mix. I rec ride mine too much to have to run race fuel all the time. If u have full control of your timing It is fine, if not then u will probably get detonation, and melt down from too much timing with ECU's. Talk to armin @ PPG for advice if u need.

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