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  1. #1

    RXT-X at Only 7900 rpm

    Got a 08 RXT-X bone stock except for a modded stock grate (side wings cut flush). Only getting about 7900 - 7950 rpm and 65mph GPS. The ski has 18 hrs on it. I weigh 170 lbs. Is this normal? Other stock RXT-X's on this site seem to be getting between 67 - 70 mph. Any ideas? Thanks.


  2. #2
    West Texas RXP skoepp's Avatar
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    Quote Originally Posted by EDondo View Post
    Got a 08 RXT-X bone stock except for a modded stock grate (side wings cut flush). Only getting about 7900 - 7950 rpm and 65mph GPS. The ski has 18 hrs on it. I weigh 170 lbs. Is this normal? Other stock RXT-X's on this site seem to be getting between 67 - 70 mph. Any ideas? Thanks.
    You need to get your rpms up to 8,000 - 8,060 rpm.
    You need some pitch taken out of your prop for this time of year (heat).

  3. #3
    subparwelder's Avatar
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    Quote Originally Posted by EDondo View Post
    Got a 08 RXT-X bone stock except for a modded stock grate (side wings cut flush). Only getting about 7900 - 7950 rpm and 65mph GPS. The ski has 18 hrs on it. I weigh 170 lbs. Is this normal? Other stock RXT-X's on this site seem to be getting between 67 - 70 mph. Any ideas? Thanks.

    Do a kanaflex intake setup, different grate, relocate the intercooler, tdr waterbox or gut yours, get rid of the reso and buy a prop from speedfreaks and you should get about 74-76 out of it. Do it right and you will stay under $1000 in mods. Not bad for that kind of speed. Right now you probably have a small boost leak somewhere. The ic relocate with aluminum tubing, silicone couplers, and t-bolt clamps will eliminate any leaks for good.

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    H2HO's Avatar
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    Quote Originally Posted by EDondo View Post
    Got a 08 RXT-X bone stock except for a modded stock grate (side wings cut flush). Only getting about 7900 - 7950 rpm and 65mph GPS. The ski has 18 hrs on it. I weigh 170 lbs. Is this normal? Other stock RXT-X's on this site seem to be getting between 67 - 70 mph. Any ideas? Thanks.
    What were you getting BEFORE you modded the grate?

  5. #5
    I was getting about the same rpm, but didn't GPS it before the grate mod. One thing the grate mod did do was eliminate any cavitation on hole shot in rough water, but really don't know how it affected the top end as the speedo only goes to 70. It read 70 before the grate mod and 70 after the grate mod, but only 65 on GPS....surprise, surprise.

  6. #6
    After more research on the forum, would a 4" intake give me the 100 or so rpm I'm needing? How many more mph can I expect with another 100 rpm all else being stock?

  7. #7
    paulthepwner's Avatar
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    Quote Originally Posted by EDondo View Post
    After more research on the forum, would a 4" intake give me the 100 or so rpm I'm needing? How many more mph can I expect with another 100 rpm all else being stock?
    Are you riding at sea level? If you're high altitude that could be why your RPMs are down. My kanaflex setup got me well over 100 rpms (though i'm not sure how much more because now i'm on the limiter), so it's certainly a good place to start.

  8. #8
    fasted1500's Avatar
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    I am getting 8100 on my RXT-X and gps at 67... Bone stock in sunny hot south florida.

  9. #9
    SeaGoat's Avatar
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    Quote Originally Posted by subparwelder View Post
    Do a kanaflex intake setup, different grate, relocate the intercooler, tdr waterbox or gut yours, get rid of the reso and buy a prop from speedfreaks and you should get about 74-76 out of it. Do it right and you will stay under $1000 in mods. Not bad for that kind of speed. Right now you probably have a small boost leak somewhere. The ic relocate with aluminum tubing, silicone couplers, and t-bolt clamps will eliminate any leaks for good.

    74-76? LOL, this is an RXT-X, not an RXP-X. At 7950 I seriously doubt you have a boost leak. What altitude are you riding at? Your modded stock grate is fine. Do the kanaflex air intake mod and test for rpm. Then repitch your prop to achieve 8060-8100 rpms. If you haven't already done so, fill the ride plate mounting holes with marine epoxy (see "how to" thread). My T-X was running 8160 in the cold of winter with alot of pitch added to the prop and speeds in the neighborhood of 72-73. As soon as the temps cracked 80 it was down to 7900 and I bought another oem prop which required a little pitch taken off to get 8060 rpm. I'm probably running 70-71mph now. If you don't feel comfortable repitching your own prop, give speedfreak a shout.

  10. #10
    paulthepwner's Avatar
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    Quote Originally Posted by SeaGoat View Post
    74-76? LOL, this is an RXT-X, not an RXP-X. At 7950 I seriously doubt you have a boost leak. What altitude are you riding at? Your modded stock grate is fine. Do the kanaflex air intake mod and test for rpm. Then repitch your prop to achieve 8060-8100 rpms. If you haven't already done so, fill the ride plate mounting holes with marine epoxy (see "how to" thread). My T-X was running 8160 in the cold of winter with alot of pitch added to the prop and speeds in the neighborhood of 72-73. As soon as the temps cracked 80 it was down to 7900 and I bought another oem prop which required a little pitch taken off to get 8060 rpm. I'm probably running 70-71mph now. If you don't feel comfortable repitching your own prop, give speedfreak a shout.
    Agreed. I think it's bad air more than anything. Kanaflex will help a ton. I was running 68.6 bone stock with 3 bars. Kanaflex actually didn't help me any because it put me all over the limiter. Worx grate got me another MPH, and the new prop goes in soon.

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