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  1. #1
    jdbretz's Avatar
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    Need some help tuning in my impeller

    I just installed a Riva rear air, and haven't had a chance to get out on the water yet. I'm going tomorrow to try it out. Before installing the intake, my RPM's were right at 8100 and occasionally 8150. I know I will be all over the limiter now with the new intake (replaced stock air intake). I was wondering (generally speaking) how many RPM's are gained from the riva rear air so I know how much pitch to add. I am riding in around 85* air and 75* water. My impeller is stock right now. Thanks!


  2. #2
    formerly Gold06RXP Turbo Nick's Avatar
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    Befor you do anything to your prop go out and see where your at rpm wise. Dont assume you will be over the limiter just from the rear air. When I switched from the riva 3 in. intake to the rear air when I still had the stock charger I saw no gain. For the most part I think you will only see gains with the rear air if you running a bigger charger. The stock charger dosent draw enough air to see gains with the rear air from my experience

  3. #3
    jdbretz's Avatar
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    Ok thanks. I'll try it out as is, and see if I need to change anything afterwards. I appreciate the input.

  4. #4
    I hate to disagree...well....not really....I saw gains when I went to a rear air set-up on an oem sc.

    What's gonna be a big difference maker is taking that flo-rite material off and running a screen instead.

    I was all over the limiter when I built and installed my own rear air. Not understanding what was happening...I didn't see any difference either. I took my own flo-rite material off and substituted a stainless screen.....that was the ticket. I started tweeking the prop and finally saw how much the system had improved. I ended up adding 3mm to my prop while still hitting 8100 rpm....in the summer heat. After that I went to a 14/19 and took some out....till I lost a bearing and upgraded....now I'm going the other way.


    So....if it was me....with the temps cooling off....I'd add 2mm to your oem prop.

    I just noticed...you have an xs ic installed now?....deffinately add a coupla mm before you go....if it was me.

  5. #5
    richrxp's Avatar
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    Quote Originally Posted by GOLD06RXP View Post
    Befor you do anything to your prop go out and see where your at rpm wise. Dont assume you will be over the limiter just from the rear air. When I switched from the riva 3 in. intake to the rear air when I still had the stock charger I saw no gain. For the most part I think you will only see gains with the rear air if you running a bigger charger. The stock charger dosent draw enough air to see gains with the rear air from my experience
    I agree,never assume anything ,first test then do the tweaking if needed.

    Best way to go!

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