Page 1 of 2 1 2 LastLast
Results 1 to 10 of 12
  1. #1

    Join Date
    Sep 2008
    Location
    NE Ohio
    Posts
    306

    The Mod that Defies Logic

    I did several small mods over the winter and this was the first day that I put the ski thru its paces. Here is the ski spec and the problem:

    1. I have all the common intake and exhaust mods, but, the wheel has not been changed.

    2. I was running 68-69 with the R&D grate and plate.

    3. I went to the R&D 12/22 impeller and picked up 1 to 1.5 mph. I was now at 69-70. To this point I did not have any aftermarket tach. The ski always appeared to run near the limiter per the oem tach.

    4 Over the winter I installed:

    a. VX plate with Jim's mod. This plate is night and day better than the R&D plate, both speed and hook-up are improved.

    b. The R&D R2 ECM mod. My paper work indicates PO18 and program spec of R2.

    c. I also installed the Flow-rite vents, two in the front and two in the back. You can feel the heat being released by the back vents.

    d. Lastly, the pet tach was installed. For information sake it follows the factory tach fairly close and as a bench mark it water idles at 1220 rpm.

    Here is the counter intuitive issue, the ski now runs 72 plus, however, the rpm's max out at 7660. I do not think the speed is bad, but, why are the rpm's being limited to the oem level. The R2 mod should have given me a higher rpm limit.

    It is also as though the VX plate gave me the 2 mph, and the R2 mod was not done? I could understand this rpm limit if I had a tall impeller, but, this impeller is almost stock. The ski runs strong right from the gate to the max speed, it cannot be down on power it just runs too strong.

    Any thoughts?


  2. #2
    SHOBiz's Avatar
    Join Date
    Jul 2008
    Location
    Wylie, Texas
    Posts
    3,577
    ...

  3. #3
    gordon lasiter #328's Avatar
    Join Date
    Aug 2008
    Location
    katy, texas , United States
    Posts
    1,647
    +1
    28
    Quote Originally Posted by Jack B View Post
    I did several small mods over the winter and this was the first day that I put the ski thru its paces. Here is the ski spec and the problem:

    1. I have all the common intake and exhaust mods, but, the wheel has not been changed.

    2. I was running 68-69 with the R&D grate and plate.

    3. I went to the R&D 12/22 impeller and picked up 1 to 1.5 mph. I was now at 69-70. To this point I did not have any aftermarket tach. The ski always appeared to run near the limiter per the oem tach.

    4 Over the winter I installed:

    a. VX plate with Jim's mod. This plate is night and day better than the R&D plate, both speed and hook-up are improved.

    b. The R&D R2 ECM mod. My paper work indicates PO18 and program spec of R2.

    c. I also installed the Flow-rite vents, two in the front and two in the back. You can feel the heat being released by the back vents.

    d. Lastly, the pet tach was installed. For information sake it follows the factory tach fairly close and as a bench mark it water idles at 1220 rpm.

    Here is the counter intuitive issue, the ski now runs 72 plus, however, the rpm's max out at 7660. I do not think the speed is bad, but, why are the rpm's being limited to the oem level. The R2 mod should have given me a higher rpm limit.

    It is also as though the VX plate gave me the 2 mph, and the R2 mod was not done? I could understand this rpm limit if I had a tall impeller, but, this impeller is almost stock. The ski runs strong right from the gate to the max speed, it cannot be down on power it just runs too strong.

    Any thoughts?
    fuel / boost controller?

  4. #4
    mjh3ides's Avatar
    Join Date
    Jul 2007
    Location
    Jupiter, Florida
    Posts
    6,800
    +1
    2,013
    Quote Originally Posted by Jack B View Post
    Here is the counter intuitive issue, the ski now runs 72 plus, however, the rpm's max out at 7660. I do not think the speed is bad, but, why are the rpm's being limited to the oem level. The R2 mod should have given me a higher rpm limit.

    It is also as though the VX plate gave me the 2 mph, and the R2 mod was not done? I could understand this rpm limit if I had a tall impeller, but, this impeller is almost stock. The ski runs strong right from the gate to the max speed, it cannot be down on power it just runs too strong.

    Any thoughts?
    It's not the ECU limiting your rpm, it's your impeller pitch. The Skat you are running is 2* taller than the stocker & probably has more root angle too. I bet if you throw the stock prop back on your rpm will be near 8K & your top speed will pick up. You could also depitch the Skat. Talk to Hitman...he's running an upgraded IC, but I know he has been palying with pitches for the stock SC wheel with his ECU that is a similar tune to the R2.

  5. #5
    hitman's Avatar
    Join Date
    Aug 2006
    Location
    Ft. Lauderdale, FL
    Posts
    4,328
    +1
    12
    I would recommend you get a 15/19 impeller. 22 on the trailing edge is just hands down too tall for your mods. With a 15/19 and your plate mod, you should be damn close to 78 mph in cool weather. Little less than that in warmer air.

  6. #6

    Join Date
    Jul 2005
    Location
    Central North Carolina
    Posts
    3,846
    +1
    527
    Quote Originally Posted by hitman View Post
    I would recommend you get a 15/19 impeller. 22 on the trailing edge is just hands down too tall for your mods. With a 15/19 and your plate mod, you should be damn close to 78 mph in cool weather. Little less than that in warmer air.
    Good info you posted Todd, Looks like you are starting to understand the prop issues. You need to up date your info I know you are faster than 71.6 mph Now!!

  7. #7
    Boilerman Bill BPnta's Avatar
    Join Date
    Jun 2008
    Location
    Yulee, FL
    Posts
    887
    +1
    1
    Generally speaking- how many RPM are lost if you pitch the leading edge up 1 degree?

  8. #8

    Join Date
    Jul 2005
    Location
    Central North Carolina
    Posts
    3,846
    +1
    527
    Quote Originally Posted by BPnta View Post
    Generally speaking- how many RPM are lost if you pitch the leading edge up 1 degree?
    100 to 150

  9. #9
    Just want to ride.
    Join Date
    Dec 2005
    Location
    Sumner, WA
    Posts
    413
    +1
    5

    I understand

    Hello Jack,

    I get where you're coming from - it's puzzling in a sense, that your 12/22 would be just fine with the stock program, turning - let's assume - 7550-7600 rpm with no reflash, and getting you to 71ish.

    THEN, you pop for the flash, thinking hey this is going to push me to at least 8k and probably 75 - guys all over the boards are getting that no problem. Hell, I should be 75 NO problem.......

    And it doesn't work. Why? I've wondered the same thing a little bit - MY ASSUMPTION is that the reflash doesn't change enough to really 'unlock' your motor, like a MOTEC/VIPEC would, so using the stock supercharger, intercooler, etc. aren't really maximized the way the custom maps are with the standalone systems. You either go closer to stock on the prop to get the RPM up (which adds speed), or you add another component or two to give the flashed ECU more to work with......

    I admit, I would have expected more that 7660 from your setup though.

    Good luck!
    Sean

  10. #10

    Join Date
    Sep 2008
    Location
    NE Ohio
    Posts
    306
    Quote Originally Posted by hitman View Post
    I would recommend you get a 15/19 impeller. 22 on the trailing edge is just hands down too tall for your mods. With a 15/19 and your plate mod, you should be damn close to 78 mph in cool weather. Little less than that in warmer air.
    On the FZ the 12/22 is basically a stock pitch. There are slightly modded ski's bouncing off the oem limiter. It seems to be a bit on the low side. I am going to start logging, this might give a bit mpre insight. There was a slight chop, it will probably go 73-74 in calm water with a some trim.

Page 1 of 2 1 2 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Let's talk about mods that actually work on the svho
    By riick370 in forum Yamaha PWC Performance (4-stroke)
    Replies: 59
    Last Post: 06-17-2015, 10:45 AM
  2. RXPX260 Mods that won't void the warranty
    By MarineBoy in forum 4-Tec Performance
    Replies: 24
    Last Post: 05-21-2015, 05:49 AM
  3. Replies: 0
    Last Post: 07-02-2011, 10:21 PM
  4. What are the minimum mods that can be done and effectively spin a 14/20 DF
    By o uncola o in forum Yamaha PWC Performance (2-stroke)
    Replies: 15
    Last Post: 12-25-2008, 06:05 PM
  5. What Are The Best Mods That Won't Effect Warranty?
    By ercBOOSTED in forum Kawasaki PWC Performance (4-stroke)
    Replies: 2
    Last Post: 05-21-2007, 06:39 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •