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  1. #1

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    How much RPM drop when upgrading props?

    I know this has been discussed before, but I'm finding it hard to formulate the search criteria to bring up exactly what I need.

    I'm spinning perfect (8100) with the Green SC wheel and a S.C. 13/18 with one or two mms of pitch added. The 13/18 is really limiting my top speed though. I'm adding an XS IC and 42lb injectors. I'm undecided between a 14/19 or 15/20; is a 15/20, depitched a little, going to be way too much?

    What would be the expected RPM drop, with no other changes, when moving up from a 13/18 to 14/19, 15/20, etc.?

    Thanks-


  2. #2
    1BAD07RXP's Avatar
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    Well I have a stage one steup plus green wheel and bov and iam hitting the rev limiter in the holeshot so they told me to pitch it 2 mm and so iam guessing you will need the 15/20 ONCE you do the upgrades you are talking about or just send it to impros and they will do all the pitching to it you will need.

  3. #3

    15/20

    get a 15/20..... do all of your mods before bending. then get the adjustable nozzle setup so you can fine tune for weather etc.

    Jerry has them in his store or there are some on ebay.(props and nozzles)

  4. #4
    Scotty's Avatar
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    I think a 15/20 might be to much for a boat. I run a 15/20 on a gtx with S3 SC, ext. IC, and 42# injectors. It is turning 8100 to 8160.

    Scott

  5. #5

    15/20

    sorry i did not see that it was a boat

    i do not know

  6. #6
    Scotty's Avatar
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    Quote Originally Posted by DIGGS View Post
    sorry i did not see that it was a boat

    i do not know
    I don't know on a boat either. A 14/19 might still be to much.

  7. #7

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    Solas is listing the 14/19 as the way to go for a stock boat, on their new recommendation chart:

    http://www.solas.com/products/pwc/im...o=F23&SwType=1

    BUT, I'm pretty sure that not much thought was put into that, since before, they were recommending 13/18 for a stock RXP and 14/19 for stage 1.

    Since I had to add pitch to the 13/18 after the SC wheel to bring the RPMs down to 8100, I'm just wondering how close I am to being pitched 19 on the trailing edge already. Could I assume that, since I can spin an untouched 13/18 to 8200rpms, that adding a 14/19 will knock me all the way down to 7800 (then the ext. IC would get me back to 8000+)? I ask this here because you guys have the most experience in going up in pitch.

    I HOPE to not have to not do any significant power mods after the IC & injectors, but I just don't want to under-buy another prop.

  8. #8
    Scotty's Avatar
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    I don't know Scott. I was thinking the big weight difference. I thought a 15/20r was going to be to much for what I had because I had a rr sc at that time. Then went to the S3. The man of the site here told me to definatly get the 15/20r and as usual he was right. Maybe some of the other boaters can help you out.

    Scott

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