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

Thread: Optimal Timing

  1. #1
    '02GPRider's Avatar
    Join Date
    Nov 2005
    Location
    Minnesota
    Posts
    425

    Optimal Timing

    I did some experimenting this spring with ignition advance on my Advent. Last year I ran the YAM-84 curve and found the timing was too advanced at 5000 RPM for long distance cruising and caused some detonation. I also didn't like the way it started out at 25* so I kept my idle at 15*. Per Lowell's recommendation, I kept only 1* of separation between cyls #1 & #2 and another 2* of separation between cyls #2 and #3. Using #1 as a reference and 7000 to 7250 as my WOT range, I tried everything from 13* to 23* in 2* increments. 13* and 15* were too slow and sluggish. For the 17* to 23* curves, I was able to test back to back within minutes and found that 19* was optimal for my ski. I gained 30 RPM's compared to 23* like the YAM-84 curve.


  2. #2
    philip_gpr's Avatar
    Join Date
    Dec 2005
    Location
    Canada
    Posts
    2,724
    +1
    3
    good info

    what is you compression?

  3. #3

    Join Date
    Apr 2006
    Location
    South MS
    Posts
    1,095
    Great testing It pays off. Timing is everything

  4. #4
    '02GPRider's Avatar
    Join Date
    Nov 2005
    Location
    Minnesota
    Posts
    425
    Quote Originally Posted by philip_gpr View Post
    good info

    what is you compression?
    156 psi across the board. Squish is .052"

  5. #5
    Duke's Avatar
    Join Date
    Jul 2006
    Location
    Florida
    Posts
    10,004
    +1
    406
    So, I take it you went to MSD? Or did you have a custom curve burned in the Advent?

    The 59 curve has the same pattern as the 84 above 5000 with a less advance down low. Works great for me when cruising.

  6. #6
    Robsauto2's Avatar
    Join Date
    Aug 2005
    Location
    Oceanside, CA.
    Posts
    774
    +1
    7
    Very good info. Maybe that is why I turn more rpms with the stock ignition than my advent on curve 84. I have the same compression as you. I have a new head with less compression coming from Lowell, and will try back to back testing with the advent vs stock. I think more comp turns more rpm with less total advance, and less comp turns more rpm with more advance. Will test soon I hope.

  7. #7
    '02GPRider's Avatar
    Join Date
    Nov 2005
    Location
    Minnesota
    Posts
    425
    Quote Originally Posted by Duke View Post
    So, I take it you went to MSD? Or did you have a custom curve burned in the Advent?

    The 59 curve has the same pattern as the 84 above 5000 with a less advance down low. Works great for me when cruising.
    No MSD, everything else is stock. I had 4 custom curves done on the Advent, all ending at different points of advance. As for the 59 curve, it's still too high from 7000 RPM on, at least for my ski.

  8. #8
    '02GPRider's Avatar
    Join Date
    Nov 2005
    Location
    Minnesota
    Posts
    425
    Quote Originally Posted by Robsauto2 View Post
    Very good info. Maybe that is why I turn more rpms with the stock ignition than my advent on curve 84. I have the same compression as you. I have a new head with less compression coming from Lowell, and will try back to back testing with the advent vs stock. I think more comp turns more rpm with less total advance, and less comp turns more rpm with more advance. Will test soon I hope.
    Thanks! I thought I'd share what works for me. There's not much info posted about timing curves. Not only did I gain 30 RPM's, but the ski idles much better, too. If you're going to run stock Advent curves, try the YAM-94 vs the YAM-84 and see if you gain any RPM's.
    Last edited by '02GPRider; 05-21-2007 at 08:36 AM.

  9. #9
    Robsauto2's Avatar
    Join Date
    Aug 2005
    Location
    Oceanside, CA.
    Posts
    774
    +1
    7
    So how were you able to change to all those different the curves? I only have 4 pre-set in mine.

  10. #10
    '02GPRider's Avatar
    Join Date
    Nov 2005
    Location
    Minnesota
    Posts
    425
    I only did the 17*, 19*, 21* and 23* back to back. Prior to that bunch, I had curves that included 13* and 15*. However, there was a programming bug with my Advent that made my gauges non-functional. Since Advent said they would re-program it for free, I decided to try the 17* to 23* range.

    When I tested, I only had two bolts holding the electrical box together and used giant tie-wraps to attach it to the battery box. That allowed me to make a switch change in about 3 minutes.

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. Cam timing means EVERYTHING!!!
    By Green Hulk in forum 4-Tec Performance
    Replies: 21
    Last Post: 05-20-2007, 06:43 PM
  2. RXP idle-60 mph times?
    By watermedic in forum 4-Tec Performance
    Replies: 11
    Last Post: 08-20-2006, 08:34 PM
  3. How did you modify your craft? all at once or 1 at a time?
    By theantiRXP in forum 4-Tec Performance
    Replies: 12
    Last Post: 05-14-2005, 05:44 AM
  4. First time out with stage 1 05 RXP Not happy.
    By Fastcat in forum 4-Tec Performance
    Replies: 17
    Last Post: 05-10-2005, 09:03 PM
  5. The RXP is 10 times the ski the GPR is
    By LiquidDI in forum Sea Doo Open Discussion
    Replies: 23
    Last Post: 05-09-2005, 04:29 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
  •