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  1. #1

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    Scom / repitched impeller

    I spoke with dave at impros today he told me he has repitched a lot of 300x impellers for people running the speed delimiters..mainly to drop rpm`s around 200 he said this is where the ultra`s power is made. (7700-7800) surely someone on this board has tried this.possibly 1-2 mph gain from this.Noone on here has tried this?


  2. #2
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    I have repitched my prop yes of course it'll gain MPH but am on a different set up and I have a huge prop pitch but yes if you can get some one that knows what he is doing and he is able to drop it from 8000 rpm to 7800 it'll be perfect

  3. #3
    I've been saying this all along. For all the people worrying about turning 7,900-8K with the SCOM, an inch of pitch would get it back down to 7,700-7,800, increasing speed a possibly reliability over the long run.

  4. #4
    Moderator #985 lasportsmn's Avatar
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    But the question is has someone actually tried this. If so did it work or not? What were the results? Will they actually tell us if they did?

  5. #5
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    I'm not worried about spinning this engine at 8k rpm, with 93 octane (all I run) it will do that all day long. Yes you might pick up 1 mph on top but the awesome holeshot will be sacrificed. This ski has never been about big top speed numbers and never will be, let it go - stop vainly pursuing fractional increases in speed and kick FZR/GPR ass the old fashioned way: whenever there is much more than a ripple in the way

  6. #6
    Moderator #985 lasportsmn's Avatar
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    Quote Originally Posted by yzf-r1 View Post
    I'm not worried about spinning this engine at 8k rpm, with 93 octane (all I run) it will do that all day long. Yes you might pick up 1 mph on top but the awesome holeshot will be sacrificed. This ski has never been about big top speed numbers and never will be, let it go - stop vainly pursuing fractional increases in speed and kick FZR/GPR ass the old fashioned way: whenever there is much more than a ripple in the way
    It is not about speed at all, I am not wanting to gain any speed, just not loosing any. It is about having a ski that is running a 300 mile race. I do not care at all if it runs exactly the same speed as it is now at 8000+. If it runs the exact same speed I am thrilled. Less wear and tear on my engine and less fuel consumed.
    The other thing is as you know there is a point where after the engine reaches its optimal performance it drops off. IF the optimal RPM is 7800 and it begins to drop off after that(in stock form) why turn it any higher effectively loosing HP. Look at any dyno sheet of anything over a certain RPM an engine looses HP and Torque

  7. #7
    Quote Originally Posted by lasportsmn View Post
    It is not about speed at all, I am not wanting to gain any speed, just not loosing any. It is about having a ski that is running a 300 mile race. I do not care at all if it runs exactly the same speed as it is now at 8000+. If it runs the exact same speed I am thrilled. Less wear and tear on my engine and less fuel consumed.
    The other thing is as you know there is a point where after the engine reaches its optimal performance it drops off. IF the optimal RPM is 7800 and it begins to drop off after that(in stock form) why turn it any higher effectively loosing HP. Look at any dyno sheet of anything over a certain RPM an engine looses HP and Torque
    Exactly !. you may gain 1-2 mph, you may gain nothing, it certainly wouldn't hurt turning the motor 200 less rpms while making the same or better speed.

  8. #8
    Moderator #985 lasportsmn's Avatar
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    http://s242.photobucket.com/albums/f...vs-ReFlash.jpg

    Reaches peak HP at 7800
    Peak torque at 5800
    With a stock ECU.....
    I am running stock ecu and no other type of fuel management system. Only the SCOM and a few bolt ons. Stock class legal ski. I am sure this discussion would be different with a reflash, Motec, etc. This was asked with only a SCOM. I am learning through these forums I am knowing less and less everyday but with the little bit of knowledge I have left I would think that I would agree with Dave on this.

  9. #9
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    If I'm reading that Dyno sheet correctly, 330 HP with mods at about 8200 rpm which is damn impressive, torque drops off but that's normal. What is the mod list?

  10. #10
    Moderator #985 lasportsmn's Avatar
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    That particular one is only an ECU reflash. Yes 330 HP. Another discussion that we can not have on this forum. It is on the other forum though.

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