Thread: Optimal Timing
05-20-2007, 10:43 PM #1
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.
05-20-2007, 10:47 PM #2
05-20-2007, 10:47 PM #3
- Join Date
- Apr 2006
- South MS
Great testing It pays off. Timing is everything
05-20-2007, 11:01 PM #4
05-20-2007, 11:46 PM #5
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.
05-21-2007, 02:02 AM #6
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.
05-21-2007, 08:27 AM #7
05-21-2007, 08:33 AM #8
Last edited by '02GPRider; 05-21-2007 at 08:36 AM.
05-21-2007, 10:39 AM #9
So how were you able to change to all those different the curves? I only have 4 pre-set in mine.
05-21-2007, 10:45 AM #10
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.
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