Quote Originally Posted by vilefly View Post
If it truly controls dwell by itself, then it would have no need for the EST signal at all.
EST being the white wire? Are you implying the LTCC module has it's own spark advance tables?

Adding a buck-boost circuit to power the coils with > 14.4v adds part count and would significantly increase cost. Considering this and the difficulties I see in writing the controller firmware, the LTCC module seems very reasonably priced. I may just buy one eventually but right now my toy fund is severely depleted.

If I had a way to produce a cad drawing of the trigger wheel quickly I'd draw up some graphics to illustrate. But I just don't have time. Here's the best I can do with words.

Let's assume some generic constants - 5ms coil charge time, and 30 degreees spark advance. 1000RPM idle and 6000RPM wot with these same constants. Please double-check my math.

Code:
RPM            1000        6000
Crank Rev. Time (360d)    60ms        10ms
Cam Angular Velocity    0.333ms/d    0.0556ms/d
Cam deg - 5ms dwell    15 deg        90 deg
Spark advance in ms    4.995ms        0.834ms
Cyl 1 Dwell Strt (cam)    30d btdc    105d btdc
Cyl 1 Dwell Strt (crnk)    60d btdc    210d btdc
What I'm hoping you take from this is that at 6000 rpm the #1 coil pack will need to start charging 15 cam degrees before the #2 low res slot is encountered, or approximately the same time the #2 coil is fired. And 30 degrees advance at 6k rpm is fairly tame at 100kpa.

This has been a very valuable learning experience. I've learned that the factory coil must have really low impedance and charge time. At the same time I can't help but think I'm probably losing power above 5500 rpm due to weak spark.