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  1. #1

    how much pitch will I need to add?

    You guys with the S3 SC, how many RPM did you gain over a stock SC? Or same goes for anyone running a RR wheel and spacer for the 215 housing or a XSC since they're all pretty comparable from what I've been told.

    People with the GH waterbox how many RPM did you gain? If you flared the J-pipe too, how many RPM did you gain?

    I'm trying to figure out where I'm going to be at. Last year at this time of year I was turning 7900 RPM with my stage 2 setup. This year I added a GH waterbox, flared J-pipe, and a RR wheel and spacer for the 215 SC housing (yes, 42# injectors too). How many RPM are these additions worth? I should be on the limiter at WOT right? Any ideas on how much pitch is going to need to be added to my untouched 15/20R? I plan on replacing my current Riva 3" intake with a Riva rear air within the next 2 weeks too, but I'm not concerned about that at the moment since I've heard plenty of reports saying it's worth another 150 RPM or so over my current intake.


    Thanks fellas.


  2. #2
    kp04rxp's Avatar
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    Rex,

    Check out my setup in my signature, I don't have the exact rpms for you.. wish I did but I can tell you I am running a 15/20r which I recently removed pitch from... It is now a 15/18ish (removed 2mm) This had to be done due to temp. increase in both the water and air. Last weekend I ran 80.5mph 8550 rpms. E temp was 80 and L temp was 70. I'm also running an 83mm ring.

    Hope that helps, let me know if you have any questions.

  3. #3
    JFizzleJR's Avatar
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    The ECU difference between you two really makes it a whole other ball game. It sucks because we like to help each other, but the props just don't act the same at different RPMs.

    My suggestion is to run a 15/20r out of the box pitch. It should be pretty darn close to perfect RPMs at your elevation and current temperatures. Now, of course your RPMs will rise and drop due to weather conditions, but that's what the adjustable nozzle is for.

  4. #4
    Quote Originally Posted by JFizzleJR View Post
    My suggestion is to run a 15/20r out of the box pitch. It should be pretty darn close to perfect RPMs at your elevation and current temperatures. Now, of course your RPMs will rise and drop due to weather conditions, but that's what the adjustable nozzle is for.
    Well the lowest RPM I ever saw during the summer heat and my elevation was 7900 RPM. Highest I ever saw was in the cool spring weather and that was 8100 RPM, but I don't care about that 8100 RPM since that only last for a couple weeks (50*F water and 60*F air). I don't want to go with an adjustable venturi unless I feel I have to later in the year. I really don't want to give up any hole shot for now. So James you're saying that from the addition of the RR wheel and spacer, GH waterbox and J-pipe flare that I'll only see a 200 RPM increase?

  5. #5
    dv8rxp's Avatar
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    I would think you would need +2mm on the 15/20 because your using the stock nozzle correct. I don't use the reduction nozzle and I'm using an impros pitched 15/21 and getting 8100rpm. I have rr wheel(not the one with spacer), riva i/c, riva 3" intake, gutted waterbox, riva thru hull, riva wedge, pro b/o,riva intake grate, 42's and free mods. I think thats about it . So you will make more power with the spacer wheel, other than that, we are very similar I would think. Make sure you don't run lean with the 42's.

  6. #6
    Quote Originally Posted by dv8rxp View Post
    I would think you would need +2mm on the 15/20 because your using the stock nozzle correct. I don't use the reduction nozzle and I'm using an impros pitched 15/21 and getting 8100rpm. I have rr wheel(not the one with spacer), riva i/c, riva 3" intake, gutted waterbox, riva thru hull, riva wedge, pro b/o,riva intake grate, 42's and free mods. I think thats about it . So you will make more power with the spacer wheel, other than that, we are very similar I would think. Make sure you don't run lean with the 42's.
    Yes, I am running the stock nozzle. It does look like we are very similar except I am running a XS IC. What kind of speeds are you seeing right now? I think I should be ok with the 42# injectors. People were running them with the Riva Stage 3 SC correct? If not please let me know before I blow my junk up.

    Thanks.
    Last edited by RXP-REX; 06-29-2008 at 11:46 AM.

  7. #7
    JFizzleJR's Avatar
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    I have no experience with the flared j-pipe and I saw no RPM gain with the shorty box. Maybe you'll need to add 1 or 2mm. Only one way to find out I guess

  8. #8
    Quote Originally Posted by JFizzleJR View Post
    Only one way to find out I guess
    True story there. Can't debate that. To be honest I would be happy if I didn't have to repitch until the cooler weather comes around. That just saves me some time and keeps me on the water.

    Going to have to get this rear air ASAP. Need more speed! And it's just fun wrenching on these things. I've got nothing better to do.

  9. #9
    www.bluraycomics1.com bluraycomics's Avatar
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    Tachin out at hole shot

    Does anybody have any suggestions on what prop would work best for my setup? I'm hitting 8250 from the hole shot and tachin out, this is after a test run after just recently adding the external intercooler. Thanks for any help!

    05 RXT: Riva Free flow exhaust, Riva Intake grate, R&D 2.5 pump wedge, XS Power external intercooler, shaved reverse bucket.

  10. #10
    welcome

    Put a better air intake on that ski and find a nice 14/19 to play with.

    Is that your black ski?

    I've seen you around.

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