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  1. #1
    Gus13letter's Avatar
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    Need repitch to drop 80 RPM. Suggestions?

    From what I understand my RPM need to drop 80 RPM. I am running 8180 with 83mm nozzle at 73.3 MPH and running 82mm nozzle put me at 8160 RPM, but dropped me to 72.8 MPH, and 81mm nozzle put me to about 8160/8140 but I didnt like the way the power felt at all. I was going to send my impeller to Impros to have it specked and or repitched to run 83mm nozzle.
    Any one know of any local place or have suggestions to what it should be pitched to? I would like to have it done by next weekend so I dont have time to send it out to CA.


  2. #2
    Bend it yourself...add a mm to the trailing edge.

  3. #3
    rxpvic's Avatar
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    Gus talk to Jim, he pitch my prop.

  4. #4
    Gus13letter's Avatar
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    Quote Originally Posted by VaRedneck View Post
    Bend it yourself...add a mm to the trailing edge.
    I just spent $300 on the impeller, I am not bending on it not knowing the first thing about it.
    Last edited by Gus13letter; 07-17-2008 at 09:36 PM.

  5. #5
    Gus13letter's Avatar
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    Quote Originally Posted by rxpvic View Post
    Gus talk to Jim, he pitch my prop.
    Thanks, I sent him a PM. I remember Nate saying that too. Did you see more top speed after he pitched it? I am thinking if it is taller it should have more top speed even though RPM go down.

  6. #6
    Quote Originally Posted by Gus13letter View Post
    I just spent $300 on the impeller, I am not bending on it not knowing the first thing about it.
    Whoa...easy there...I would'nt have suggested something so drastic if'n I figured you couldn't handle it...forget I said anything.


  7. #7
    Gus13letter's Avatar
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    Quote Originally Posted by VaRedneck View Post
    Whoa...easy there...I would'nt have suggested something so drastic if'n I figured you couldn't handle it...forget I said anything.

    Sorry, didnt mean to offend you, I just dont want to mess with it in case I screw it up. I know if you bend on it too much it will weaken it or break it. I have seen several people adding 1mm to the trailing edge, even though I am very mechanical I never saw a how too so I guess I thought it was more complicated and thought I would leave it to the pros.

  8. #8
    King_Of_Fun's Avatar
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    Quote Originally Posted by Gus13letter View Post
    Sorry, didnt mean to offend you, I just dont want to mess with it in case I screw it up. I know if you bend on it too much it will weaken it or break it. I have seen several people adding 1mm to the trailing edge, even though I am very mechanical I never saw a how too so I guess I thought it was more complicated and thought I would leave it to the pros.
    Check out the How To Section:

    http://greenhulk.net/forums/showthread.php?t=2614

    Ron

  9. #9
    Gus13letter's Avatar
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    Quote Originally Posted by King_Of_Fun View Post
    Check out the How To Section:

    http://greenhulk.net/forums/showthread.php?t=2614

    Ron
    Very good info, thank you. For some reason I could not find that thread before. By reading all the posts I also see there is a how to make your own pitch gauge, in another how to. By adding 1mm should I see an increase in top speed?

    Update - Actually just found a couple - http://greenhulk.net/forums/showthre...ighlight=pitch and http://greenhulk.net/forums/showthre...ighlight=pitch I think this is taking what I need to do a little far though. I just need about +1mm on trailing edge.
    Last edited by Gus13letter; 07-18-2008 at 07:15 AM.

  10. #10
    Gus13letter's Avatar
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    Spoke to Jim and I am just going to let him do it since he knows what he's doing. He can also confirm what pitch it is is now compared to what it is supposed to be 13/19. Thanks Vic for reminding me that he could do it.

    Also while doing a search on this topic and stock ECU rev limiter it seems you lose power after 8100 RPM using stock ECU, so I definately need to get this done. Keeping it in the 8100 sweet spot and making the impeller taller may just put me to 75 MPH. Thats probably wishful thinking, probably really see .5 - 1 MPH gain.

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