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  1. #1

    Actual HP gains from mods?

    Does anybody know how much horsepower mods like 3 or 4in intake and exhaust will actually give you? Also what's the hp per lb of boost with a external ic? Just curious.


  2. #2
    Quote Originally Posted by ruger226 View Post
    Does anybody know how much horsepower mods like 3 or 4in intake and exhaust will actually give you? Also what's the hp per lb of boost with a external ic? Just curious.
    On a 2012-2014 RXPX the formula is close to MAP x RPM / 5100 =HP

    Stock these, things are about 164 KPA at 8050 RPM gives 259 HP

    Get rid of the speed and torque limiters with a Vtech or Motec, still stock, you will end up at about 180 KPA and about 8250 RPM giving about 291 HP and about 71 MPH

    Mod some stuff to get to 195 KPA and 8500 RPM and you end up at about 325 HP and about 76 MPH

    Mod even more stuff and get to 220 KPA and 9000 RPM and you end up about 390 HP and about 80 MPH

    This all assumes you do all the typical mods that most people do at these levels.

    The older skis and the RXTX tends to be a little faster.

    Hope this helps

    Andy

  3. #3
    At 260 HP, it requires about a 60 lb injector. 0-60mph in about 5.5 sec

    At 325 HP, it requires about a 75 lb injector. 0-60mph in about 4.5 sec

    At 390 HP, it requires about a 90 lb injector. 0-60mph in about 3.5 sec

    The guys that are running the big turbos need about 115 lb injectors

    This all assumes you have your fuel pressure set to at least 45 PSI higher than the boost PSI at WOT.

    Andy

  4. #4
    Awesome info Andy - just a bit pissed on my hp vs $$$$

    279hp, so 19hp / for $8000 = $421/ per 1hp. Ouch!!

  5. #5
    Quote Originally Posted by tornado34 View Post
    Awesome info Andy - just a bit pissed on my hp vs $$$$

    279hp, so 19hp / for $8000 = $421/ per 1hp. Ouch!!
    $8000 ??? Wow

    The best way to gain HP on one of these motors is to raise RPM. MAP comes right up with it.

    Andy

  6. #6
    $8000 in fairness includes all the non performance stuff also (bilge pumps, shipping, gel coat, specialist tools etc), but still, it's still cost me $8000 on top of the purchase price to pull that hair trigger and hang on!

  7. #7
    boost junkie skidoochris's Avatar
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    Andys HP numbers could be a little on the high side
    and it also shows how inefficient these boats are
    400Hp and 0-60 in 3.5.....

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  9. #8
    Having Fun jp1300r's Avatar
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    I have posted these before. May help you get an idea on HP.
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  10. #9
    Good info but not really the answer I was looking for. I have a 08 rxp 215 i have a Riva 3in intake, gutted water box, and a thru hull is that worth maybe 5-10 hp or is that a pipe dream?

  11. #10
    The short answer is a watercraft is a sliding dyno. It takes X HP to slid Y MPH thru the water. If you go a little faster at WOT, you are making more HP. What we gave you is the ballpark HP to go each MPH.

    Hope this helps

    Andy

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