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  1. #1

    Performance question with FPP, what is wrong?


    I got 2 Seadoo GTI 04 720cc:

    Single carbs true bored 40mm
    No resonator
    Filled ride plates holes
    Iridium spark plugs

    Now I installed a Factory Pipe into one, of course I changed single carb for dual carbs (with intake). No ECW, there is a continuos water injection (no solenoid). The Ski run ok, accelerate perfect but I feel like I loss 3 mph top end speed instead gain, in fact my RPM increase about 500, but I compare speed with my other GTI (single carb stock pipe)and this second one has more top en speed.

    Did I forget something to do? According to other members is why I didnīt put the ECW(also canīt install with my mpem), and they run fine (faster)their skis without ECW.

    Engine sounds great, the problem is that I spend in Dual Carbs, Factory pipe and Doo is slower than before or worst slower than the other GTI stock for 3 mph.

    Rotary valve is fine in stock degrees (re-aligned before install dual carbs).
    And RPM really increases 500, but not the top end speed.

    What do you recommend?

    Because if I canīt fix this I think Iīm goig to return to stock pipe 'cause is faster for the ski for the moment.
    And biggest problem my wife is going to yellme the money I spend and at the end I quit the performance parts.

    Iīm sure I forgot something

    thanks in advance guys!!!

  2. #2
    Have you jetted the new dual carbs according to the new setup ?

  3. #3
    According to FPP jetting stock, or It has to be different?

  4. #4
    KrunchovXPL-GTX-RX's Avatar
    Join Date
    Mar 2009
    Aiken, SC
    Let me get this straight.

    You are turning 500 MORE RPM but it is 3mph slower, with the same prop/pump?

    That does not add up so... How are you reading the RPM and the MPH (as in, Tiny Tach, GPS, whatever)?

    Now, I gotta ask, why in the world would you spend that much money and time to go maybe 50mph at best?

    I am not trying to hate, but you could have paid less for a 951 powered GTX (granted, 2-3 years older) and been 10mph or more faster without doing a thing to it.

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