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  1. #1

    Join Date
    Aug 2022
    Location
    Puerto Rico
    Posts
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    Angry Help Hitting 90MPH

    Hello,

    I currently have a 2018 RXT 300 and trying to hit 90MPH but never hit more than 82.
    What am I missing.

    Riva Pro Filter
    Riva FPR = Currently at 47psi
    JPL 23lbs charger wheel (currently doing 20lbs at 9100RPM)
    Riva water box
    Riva Free Flow
    Riva 1100 Injector
    Scheiner Cam (retarded 2 degrees)
    Riva Fuel Rail
    Riva Catch Can
    Riva Intake Upgrade
    Dashpac with AFR reading 11 at 100% Throttle
    Solas 13/16 (had 13/18 but was not getting good RPMs)
    Flywheel and crankshaft (Balanced and lightened)
    Titanium screws everywhere
    Double valve spring with titanium retainers
    Maptunner using stage 4 (Edited idle rpm from 1700 to 1850 to compensate the cam effects)
    New Piston rings, gaskets, etc....

    I have a friend in the 90mph with less than what I have.

    What is missing???????


  2. #2

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    Forgot, Fizzle hoses with intercooler and tial blowoff

  3. #3

    Join Date
    Oct 2018
    Location
    Usa
    Posts
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    Bring up your AFR to 12 at WOT

  4. #4

    Join Date
    Aug 2022
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    Thanks!!! Ill try that Saturday, any other advise?

  5. #5
    moparguy's Avatar
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    Sep 2016
    Location
    Niagara Falls, Ontario
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    Data log and dial your tune in properly instead of trying to use rrfpr to adjust tune. All these tunes are written for 58 psi, NOT 47psi as you indicated.

  6. #6
    Site Admin Green Hulk's Avatar
    Join Date
    Apr 2005
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    Morgan City, LA
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    39,054
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    Your very first step will be getting your tune right. Get your fuel pressure back up to 58 psi where it belongs. If you don't already have the MaptunerX logging you will need it. Then use map edit to edit your tune based off of your logs.

    The logging kit is here http://www.4-tecperformance.com/inde...oducts_id=6410

  7. #7
    Mod less, ride more! troyheb's Avatar
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    Your friend may be lying.

  8. +1 by:


  9. #8
    Water4fire's Avatar
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    May 2005
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    New Braunfels TX.
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    If you are going to throw a bunch of stuff on it a once without logging use the Riva staged kits. Period. If not you need to tap the manifold and log. Period. We used to dial in the tune with fuel pressure, but now you should log and adjust the tune.


  10. #9
    Quote Originally Posted by bosch00 View Post
    Hello,

    I currently have a 2018 RXT 300 and trying to hit 90MPH but never hit more than 82.
    What am I missing.

    Riva Pro Filter
    Riva FPR = Currently at 47psi
    JPL 23lbs charger wheel (currently doing 20lbs at 9100RPM)
    Riva water box
    Riva Free Flow
    Riva 1100 Injector
    Scheiner Cam (retarded 2 degrees)
    Riva Fuel Rail
    Riva Catch Can
    Riva Intake Upgrade
    Dashpac with AFR reading 11 at 100% Throttle
    Solas 13/16 (had 13/18 but was not getting good RPMs)
    Flywheel and crankshaft (Balanced and lightened)
    Titanium screws everywhere
    Double valve spring with titanium retainers
    Maptunner using stage 4 (Edited idle rpm from 1700 to 1850 to compensate the cam effects)
    New Piston rings, gaskets, etc....

    I have a friend in the 90mph with less than what I have.

    What is missing???????
    Fuel pressure 58 PSI. I'm sure Jesus told you 58 static. Get rid of the Solas Prop. Buy the Skat 159mm prop from Riva pitched & change wear ring 159mm. Set that Cam back to stock position and or get a Calas Billet Cam. Cut some 2" holes to get more air in the hull. You need to spin that motor 9000 - 9200 RPM to get 23 PSI from that wheel. At 9100 you should see 23 PSI. CHECK THE SUPER CHARGER SLIP 18 LBS! Pitch that prop according to desire RPM. Took me a season of testing & adjustments 4 Different props to get the speed out my 2017 RXP 86MPH with 142mm wheel. I have 3 different Solas props if you want to buy one. Where are you located? Elevation has a lot to due with speed & tune. You can also go Turbo!

  11. #10

    Join Date
    Aug 2022
    Location
    Puerto Rico
    Posts
    4
    Thanks for the help!!! Im from PR BTW.

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