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  1. #1
    prostocker's Avatar
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    advice on pitch and rpms with skat trak?

    I want to know how much a drop of 0.5 from 15/21. To 15/20.5. Im on 8725 rpms with 15/21 i would like to know if drop 0.5 how many rpms i will gain. I want to be close to the limiter that is 8840. Thank you in advance remember i have a skat trak.


  2. #2

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    Quote Originally Posted by prostocker View Post
    I want to know how much a drop of 0.5 from 15/21. To 15/20.5. Im on 8725 rpms with 15/21 i would like to know if drop 0.5 how many rpms i will gain. I want to be close to the limiter that is 8840. Thank you in advance remember i have a skat trak.
    One full pitch less usualy will increase your 125-175 rpms. I doubt you can see a differance between a 20.5 and 21. Chasing 100 + rpms is almost impossible by pitching going up on reduction nozzle 1 mm is a better bet. Usualy the weather from day to day on the supercharged motors can easly change your rpms 200 + or - Trying to stay in that close of a rpm range will drive you nuts. Tommy Jordan


  3. #3
    prostocker's Avatar
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    Right now im in cold weather here and i did the test on lake because on the ocean will drop like 200 rpms ... Should i live it like that because 0.5 drop will make 100 rpms

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    Fyi when the weather warms up your rpms will decrease some. I like to pitch the prop correct with the oem 82.5 reduction nozzle @ my desired rpm in cool weather. Then as my rpm start to decrease due to the warmer weather I switch to a larger reduction nozzle like 84 or 85 mm. Then when the cool weather returns in the fall i return to my smaller 82.5 reduction nozzle to keep my rpm where I want them. Tommy Jordan
    Last edited by 2fast4u; 02-07-2013 at 05:37 PM.

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  6. #5
    prostocker's Avatar
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    Quote Originally Posted by 2fast4u View Post
    Fyi when the weather warms up your rpms will decrease some. I like to pitch the prop correct with the oem 82.5 reduction nozzle @ my desired rpm in cool weather. Then as my rpm start to decrease due to the warmer weather I switch to a larger reduction nozzle like 84 or 85 mm. Then when the cool weather returns in the fall i return to my smaller 82.5 reduction nozzle to keep my rpm where I want them. Tommy Jordan
    I understand a nozzle of 85 mm how much rpms you see in warm weather....

  7. #6
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    I am not sure but if your limiter is set at 8840 and you are at 8725 I think you are starting to hit the soft limiter?? I just dont see what would be gained buy running on the limiter in fact I would not do it. also I would adjust my RPM`s with nozzles vs always changing the pitch

  8. #7
    prostocker's Avatar
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    Its actually 8850 my limit.... The more rpms i get the more i boost thats why i want to stay close to my limiter to gain speed.

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    8850 is the max rpm limiter for the r3 but it also has a soft limiter also around 8725-8750 like Scott said which starts to cut fuel or timing slightly if I'm not mistaking, which means no increase in speed

  10. #9
    prostocker's Avatar
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    I dont know about that i have call r&d monday and find out.

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    FYI R-3 The soft limiter start is 8850 then if the rpms continue to rise above 8850 more cylinders have the ignition cut off to them progressively as the rpms continue to rise even higher. From the service manual----------------- Level 1 Ign cut off to 1 cylinders. Level 2 ign cut off to 2 cylinders. Level 3 ign cut off to 3 cylinders, level 4 ignition cut off to all cylinders .each level is 100 rpms higher than the last level. Example---------------Level 1 starts at 8850, level 2 starts at 8950, level 3 starts at 9050. level 4 starts at 9150 ( total ignition shut down) The starting point of the rev limiter is what R&D changes in the ecm to control rpms . Hope this helps. Tommy Jordan
    Last edited by 2fast4u; 02-07-2013 at 10:09 PM.

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