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  1. #1
    tasosz's Avatar
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    Question Do I need more air?

    I was testing my Riva stage 3 FZS yesterday and someone told me to remove the seat for more top speed. I did it and I got 0.5 mph more. The first run was with the back seat and bucket removed 80.6 mph @ 8050 rpm @ 14.7lbs of boost and the second without the seat was 81.1 mph. The air temp was 91 F and sea temp 80 F. The test done with half tank of fuel on salt water.
    Everything are Riva except intake grate and ride plate. Both are R&D. My exit nozzle is 85mm and I'll try 87mm because the target rpm are 8300. I don't want to repitch my impeller before I test it in colder weather.
    I have removed the two foam covers and the two hoses inside the hull.
    The difference in top speed is from the air, or from the weight of the seat or both? I'm asking this before I start to drill holes to my hull and finally, can I reach the same top speed with the seat on?


  2. #2
    What are your afr's? On my fzs I actually lost speed when I removed the back seat due to it leaning out. I had tuned it with the seat on, then removed the seat thinking I would gain something, and I actually lost speed. Looking at the afr's I saw that I had actually leaned the motor a bit.

    In theory then yes there would be something to gain with the seat on if you better ventilated the hull. However, there is a trade off in that the water needs to be kept out. Your riding conditions come into play. You don't want to be opening up holes in your hull if your gonna go wave jumping, especially in salt water.

  3. #3
    tasosz's Avatar
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    Usualy I do not jump waves trying to save my one way bearing of my SC. I like fast runs and drag races with my friends on calm water. I don't want to mess with the vipec, I run the stage 3 base map downloaded from Riva's site. Do you think an electric blower can solve the problem or someone have try this?

  4. #4
    Search the site. There are a couple threads on opening holes for better ventilation. If I remember correctly there is one where he actually turned the "fake" side cowls into working ones, and another where he only removed the foam and drilled holes in the valleys in the front cowling.

    I run in mostly salt water so I opted to only do the holes under the cowling. My bike is turbo and I have plenty or air. When your gonna line up with your friends in flat water just remove the back seat for the time being.

    More than that I would hesitate to open any more holes. Unless it was a pure flat water drag bike...

  5. #5
    I completely missed your blower idea. I doubt that any electric blower (small enough to be useful in our application) will supply enough air to keep up with your motor. Although I have thought of using one for air circulation purposes.

  6. #6
    maniacal_rick's Avatar
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    The only thing that will tell you if your Ratios are good is an A/F gauge. Until you know that, no one can tell if your lean/rich.

  7. #7
    Lightning Struck's Avatar
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    Quote Originally Posted by maniacal_rick View Post
    The only thing that will tell you if your Ratios are good is an A/F gauge. Until you know that, no one can tell if your lean/rich.
    Not true.. It might surprise a few people, but in the 100 years the internal combustion engine has been a prominent staple of society, there hasn't always been A/F gauges.. People used to rely on actually using ratchet and pulling a plug and reading it. Some people even still use this antique method, because it'll show you hole by hole what each cylinder is doing, weither it's lean, rich, burning oil, burning water, etc etc...

  8. #8
    tasosz's Avatar
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    Quote Originally Posted by Lightning Struck View Post
    Not true.. It might surprise a few people, but in the 100 years the internal combustion engine has been a prominent staple of society, there hasn't always been A/F gauges.. People used to rely on actually using ratchet and pulling a plug and reading it. Some people even still use this antique method, because it'll show you hole by hole what each cylinder is doing, weither it's lean, rich, burning oil, burning water, etc etc...

    +1000 especially for burning water! All we have a water cooled intercooler, it's like a clock bomb....it will explode but you don't know when..

    My question is if I need more air not if I'm rich/lean. If my motor needs more air, adjusting the ECU you mean to cut fuel for best AFR. Less fuel+less air=less power. Maybe I must start drilling.....

  9. #9
    After re-reading your first post I see that you are comparing speeds with only the back seat removed and then with all the seats removed. How many holes do you wanna drill? You will need to slaughter your bike to get the airflow that it has with no seats on.

  10. #10
    lets race.... mikeFZR's Avatar
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    Here is one of the best threads on getting more air into the FZ platform: http://www.greenhulk.net/forums/show...hlight=FZR+air

    IMO, the ski is dying for air, as evident by the 100 or so RPMs picked up by removing the front seat. Getting air out of the hull isn't the problem considering how much air a 1800cc engine moves. Rather, the 'problem' is finding a safe and effective way to get more air into the hull.

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