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  1. #1

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    Need some thought input.. impeller pitching!

    Someone that has more understanding about this explain to me how this works.

    I had someone repitch my solas 13/18 impeller on my '18 RXT-X. I don't know if it was right and after chasing rpms and speed, I sent both my stock and Solas impeller to Glenn at Skat Trak to repitch.

    I asked him if he needed to know what mods I have and he simply said no, "just tell me what rpm you want to turn". I told him since I have the stage 3 (at the time I didn't have a cam but do now) I wanted to turn 8900 rpm. I was using a 9200 tune modified by Jesus at Riva.

    Can you just do that? Is the result the same? I hadn't installed the stock repitched impeller in yet but the Solas turns exactly 8900 rpms. Unfortunately, I'm not even breaking 80mph.

    I'm not saying Skat trak did anything wrong, I'm trying to understand if you can pitch an impeller to turn an rpm but still not be the correct one.

    Thanks guys,

    Mark


  2. #2
    outnumbered's Avatar
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    I am not an impeller expert, but I don't see how just requesting an rpm--without asking for mods, would yield the desired result. For example, you could have a stock ski, and request 8900 rpm's, but it may ultimately result in a loss of MPH. I am fairly certain that Riva and Dean's team is going to match or tweak an impeller pitch to the mods that are on the ski. If not, to me, it's just a shot in the dark.

  3. #3
    DR2006RXP's Avatar
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    Quote Originally Posted by Orangecrush View Post
    I'm not saying Skat trak did anything wrong, I'm trying to understand if you can pitch an impeller to turn an rpm but still not be the correct one.
    2 things for you

    #1: With time comes experience, both Skat and Impros among others have got plenty of that under there belts.

    #2: 80 is a little on the low side considering it is a stage 3 and there are many factors that need to be on point to get the speed over 80 and keep it there , engine health, afr, boost, clutch slip, altitude , just to name a few is key to end results .

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  5. #4

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    Quote Originally Posted by outnumbered View Post
    I am not an impeller expert, but I don't see how just requesting an rpm--without asking for mods, would yield the desired result. For example, you could have a stock ski, and request 8900 rpm's, but it may ultimately result in a loss of MPH. I am fairly certain that Riva and Dean's team is going to match or tweak an impeller pitch to the mods that are on the ski. If not, to me, it's just a shot in the dark.

    That was my point... perhaps that's all that's needed but it seems to me, you can adjust the leading edge to turn the rpms you want but that doesn't account for how the impeller processes the flow of water to utilize the hp of the engine. I'm hoping someone on here that understands pitching and impellers can point me in the right direction.

    Personally, I think I need to just buy another Solas 13/18 impeller and start over.


    Mark

  6. #5

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    Quote Originally Posted by DR2006RXP View Post
    2 things for you

    #1: With time comes experience, both Skat and Impros among others have got plenty of that under there belts.

    #2: 80 is a little on the low side considering it is a stage 3 and there are many factors that need to be on point to get the speed over 80 and keep it there , engine health, afr, boost, clutch slip, altitude , just to name a few is key to end results .

    I can appreciate that. I'm not doubting Glenn's ability, I just don't understand why I'm not turning the numbers. Just for the record, I'm going backwards, I'm at 75mph. I was doing 79 but in my quest for speed, I've gone down with the impeller. I have to sort out my air fuel ratio. I installed an O2 sensor with the dash pac unit and I think I need the manifold spacer to bring it in correctly. Beginning of this year, it was showing really lean (18's) at WOT and clearly it's a misreading. If that were true, I would have burnt a hole in the piston.

    I need to take a few steps back and bring some stuff back to "normal". (ie. tune, impeller, etc, etc) so I can get a baseline. Too many variables, too many things "tweaked". (again, impeller and tune) Need to get a correct a/f number reading, a stock 13/18 impeller and a stock 9200 tune.


    Mark

  7. #6
    DR2006RXP's Avatar
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    So you was at 79 with the stage 2 mods ? At what rpm?

  8. #7

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    Quote Originally Posted by DR2006RXP View Post
    So you was at 79 with the stage 2 mods ? At what rpm?

    LOL... no, I was at 79 with the stage 3 mods at 8900 rpms.

    Now I've installed the cam and it went down to 75. smh... I'm going backwards. That's why I want to start from scratch and get some baseline numbers.

  9. #8
    DR2006RXP's Avatar
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    Quote Originally Posted by Orangecrush View Post
    LOL... no, I was at 79 with the stage 3 mods at 8900 rpms.

    Now I've installed the cam and it went down to 75. smh... I'm going backwards. That's why I want to start from scratch and get some baseline numbers.
    Confirm the timing in the motor after you replaced the cam .

  10. #9

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    Quote Originally Posted by DR2006RXP View Post
    Confirm the timing in the motor after you replaced the cam .
    Actually, that was part of the reason I replaced the cam. I wanted the add'l hp but I was fearful that the timing was off from the factory. I've heard stories of different timing of up to 6 degrees off)

    Anyway, explained my concerns to the tech at the dealership and he doublechecked cam timing for me when he installed new cam.

    Mark

  11. #10
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    Quote Originally Posted by Orangecrush View Post
    LOL... no, I was at 79 with the stage 3 mods at 8900 rpms.

    Now I've installed the cam and it went down to 75. smh... I'm going backwards. That's why I want to start from scratch and get some baseline numbers.
    . Ok when introducing a cam you are allowing a lot more air to be processed thru the engine. Without adjusting fueling your AFR’s will be off. Dial in tune and then see where you are. Believe me you will be surprised with the “free hp” you will unleash

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