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  1. #1
    Self Confessed Day Dreamer toomanytoys's Avatar
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    300x Full Boost at 7600 RPM

    Long story short, I put a 14/21 Solas impeller in my ski (thanks Corey).

    It wasn't a night and day difference. In fact it was hard to tell any difference. Maybe it had a very slight improvement out of the hole, but again it was so hard to tell.

    What it did though was pull my rpms back by about 200-300 rpm. My top speed pretty much stayed the same but I was maxing about 7600 RPM.

    During a speed run, in only 25 degree C/77F my boost was full. Every single bar was lit(even the last little quarter bar). Now the air was cool, and I've recently cleaned the IC, but I still was surprised. I didn't think this was right given the low RPM.

    What are your thoughts guys?


  2. #2
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    300x Full Boost at 7600 RPM

    Normal for the rpm reduction that's a benefit. If you coukd not tell the hook up diff that's weird.

  3. #3
    "just sayin".. jetdave56's Avatar
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    7600 sounds awfully low...with air temps reasonable and custom air mods and clean IC I would think 7800 would be right with that prop...IMO

  4. #4
    Self Confessed Day Dreamer toomanytoys's Avatar
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    Yep, it pulled the revs back quite a bit. Stock, in that temp, would have been 7900 maybe higher. Winter on stock prop is 8200+

    It's the boost I'm mainly talking about though. Full Boost at 7600 RPM seemed weird.

  5. #5
    Vman's Avatar
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    I would have thought that a 2-300 rpm loss would equate to some loss in boost psi...

  6. #6
    UltraKvz's Avatar
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    Maybe your engine is using less air(therefore surplus on boost gauge) at that rpms but same feul(richer) due to bigger load!? You maybe need a tune?

    Quote Originally Posted by toomanytoys View Post
    Long story short, I put a 14/21 Solas impeller in my ski (thanks Corey).

    It wasn't a night and day difference. In fact it was hard to tell any difference. Maybe it had a very slight improvement out of the hole, but again it was so hard to tell.

    What it did though was pull my rpms back by about 200-300 rpm. My top speed pretty much stayed the same but I was maxing about 7600 RPM.

    During a speed run, in only 25 degree C/77F my boost was full. Every single bar was lit(even the last little quarter bar). Now the air was cool, and I've recently cleaned the IC, but I still was surprised. I didn't think this was right given the low RPM.

    What are your thoughts guys?

  7. #7
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    300x Full Boost at 7600 RPM

    It takes allot to turn a 14/21. Ether that or time for another leak down

  8. #8
    Self Confessed Day Dreamer toomanytoys's Avatar
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    I'll put the stock prop back in next week and test again. It was just odd to see all the boost bars up at such low RPM. It did this not long after I got the 300x. Normally I'm 1 or 2 bars from the top.

  9. #9
    fx160's Avatar
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    300x Full Boost at 7600 RPM

    Mal could it be that the boost is being bled off at the higher rpm

  10. #10
    Self Confessed Day Dreamer toomanytoys's Avatar
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    It shouldn't be able to. There is a blow off valve (more like a relief valve) that will open at a set boost level, independent of RPM. Then there is a bypass valve (which functions more like a traditional blow off valve).

    I'll see what happens today. It'll be very hot on the water today so I'll be down on power. It will be interesting to see revs and boost. I'll post back up this afternoon.

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