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  1. #1

    Help with 03 Sportster 4 TEC Mods

    Just bought a used Sportster 4 Tec and looking for a couple of mods I can do to start with to increase the bottom end power and top end speed. Anyone try the Adjust A Thrust? Which impeller will give me the best performance? Any air intake suggestions? Etc....


  2. #2
    somefun's Avatar
    Join Date
    May 2006
    Orange CT
    Air Intake is the best bang for your buck. What prop do you have on it now and what RPM does it run at WOT?

  3. #3
    Moderator RX951's Avatar
    Join Date
    Apr 2005
    League City, Texas
    Welcome to the Forum

  4. #4
    Quote Originally Posted by RX951
    Welcome to the Forum
    I have an 05 sportster 4-tec, stock it was 7100rpms and only 38mph on the speedo. Replace the airbox with a cone filter on the stock intake tube and went up to 7500 rpms and 43mph on the speedo. Those speeds arent on gps, so allow for some error, but there was a definet improvement. The boat is rated at 51mph everywhere I have seen a review, and that concerns me a little with how fast my boat is going. Is that speed overrated or could there be something wrong with my motor, pump etc

  5. #5
    iron head's Avatar
    Join Date
    Aug 2006
    The RPM should be at 7900 to 8000 I run 56.7 on GPS with stock intake hose next year I will put the 4" intake hose on

  6. #6
    Quote Originally Posted by iron head
    The RPM should be at 7900 to 8000 I run 56.7 on GPS with stock intake hose next year I will put the 4" intake hose on
    I dont have the SCIC, the rpms and top speed are lower on the n/a model. Mine seems to be holding back a little on the top end. Over the winter I'll get it tuned up and see how things run in the spring.

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