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  1. #1
    DaveC's Avatar
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    RXTX w/ Vtech mods.

    '14 RXTX. that ran 68 at 7960-8000 RPM on GPS stock at 10 hours.

    i have not seen 8000 RPM since that one run. Added the Vtech reflash 48 8375 36 33 80 AGR, with this I ran 70.4 at 7880 with everything else stock.

    I then added a Solas 15/19R, 4" air intake to the front and ran the same reflash and got 71 mph at 7940.

    I then tried the 48 8375 35 34 -50. With that and everything else the same I got 69.4 at 7800-7820.

    Im doing all this at 1050 elevation, temp was 82* with 60 % humidity. I'm not logging or checking AFR, but numbers seem low.


  2. #2
    JFizzleJR's Avatar
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    Quote Originally Posted by DaveC View Post
    '14 RXTX. that ran 68 at 7960-8000 RPM on GPS stock at 10 hours.

    i have not seen 8000 RPM since that one run. Added the Vtech reflash 48 8375 36 33 80 AGR, with this I ran 70.4 at 7880 with everything else stock.

    I then added a Solas 15/19R, 4" air intake to the front and ran the same reflash and got 71 mph at 7940.

    I then tried the 48 8375 35 34 -50. With that and everything else the same I got 69.4 at 7800-7820.

    Im doing all this at 1050 elevation, temp was 82* with 60 % humidity. I'm not logging or checking AFR, but numbers seem low.
    You'll need to pitch the prop or open the nozzle up or add more power. RPMs aren't going to increase by 400 from changing from one Vtech tune to another similar one.

  3. #3
    DaveC's Avatar
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    That was pretty much what I was thinking on pitching the prop. As far as the different Vtech flashes, the Aggressive tune definitely felt better. Just not sure how much I like it in some of the chop as the throttle is touchy.




    Quote Originally Posted by JFizzleJR View Post
    Quote Originally Posted by DaveC View Post
    '14 RXTX. that ran 68 at 7960-8000 RPM on GPS stock at 10 hours.

    i have not seen 8000 RPM since that one run. Added the Vtech reflash 48 8375 36 33 80 AGR, with this I ran 70.4 at 7880 with everything else stock.

    I then added a Solas 15/19R, 4" air intake to the front and ran the same reflash and got 71 mph at 7940.

    I then tried the 48 8375 35 34 -50. With that and everything else the same I got 69.4 at 7800-7820.

    Im doing all this at 1050 elevation, temp was 82* with 60 % humidity. I'm not logging or checking AFR, but numbers seem low.
    You'll need to pitch the prop or open the nozzle up or add more power. RPMs aren't going to increase by 400 from changing from one Vtech tune to another similar one.

  4. #4
    Mod less, ride more! troyheb's Avatar
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    Sounds like the tunes you are trying are not matching your mods. Thus holding the ski back some.

  5. #5
    Mod less, ride more! troyheb's Avatar
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    You should be able to spin that 15/19 better than what you are doing.

  6. #6
    JESUS G's Avatar
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    You have to check AFR numbers ....i think your impeller also is big to run at your elevation.

  7. #7
    DaveC's Avatar
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    I was guessing that I would have been well over 8,000 RPM



    Quote Originally Posted by troyheb View Post
    You should be able to spin that 15/19 better than what you are doing.

  8. #8
    1tommygunner1927's Avatar
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    Quote Originally Posted by DaveC View Post
    '14 RXTX. that ran 68 at 7960-8000 RPM on GPS stock at 10 hours.

    i have not seen 8000 RPM since that one run. Added the Vtech reflash 48 8375 36 33 80 AGR, with this I ran 70.4 at 7880 with everything else stock.

    I then added a Solas 15/19R, 4" air intake to the front and ran the same reflash and got 71 mph at 7940.

    I then tried the 48 8375 35 34 -50. With that and everything else the same I got 69.4 at 7800-7820.

    Im doing all this at 1050 elevation, temp was 82* with 60 % humidity. I'm not logging or checking AFR, but numbers seem low.
    Dave......its running too lean and timing is being retarded. You need to add at a minimum, a RRFPR and use the rising rate. Don't run it at WOT until you add the RRFPR.

  9. #9
    DaveC's Avatar
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    Hi Bob, I guess that is possible. Same setup as others are running without any problems and was suggested as a mild tune


    Dave......its running too lean and timing is being retarded. You need to add at a minimum, a RRFPR and use the rising rate. Don't run it at WOT until you add the RRFPR.[/QUOTE]

  10. #10
    1tommygunner1927's Avatar
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    There's nothing wrong with the tune, you just need to feed it more fuel!

    Quote Originally Posted by DaveC View Post
    Hi Bob, I guess that is possible. Same setup as others are running without any problems and was suggested as a mild tune


    Dave......its running too lean and timing is being retarded. You need to add at a minimum, a RRFPR and use the rising rate. Don't run it at WOT until you add the RRFPR.
    [/QUOTE]

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