[Diy_efi] Definitive LS1/LS2 coil information

[Dave B]

I've done a *lot* of searching on the 'net and the archives.  Some of the
information I've found has been helpful, but a lot of it has been
inconsistent.

I have a set of LS2 coils (the newer, round style) that I will be using for
experimentation.  These are the 4 pin style.

Apparently, the 4 pins are 12volt power, power ground, logic ground and a 5
volt logic trigger.  They start charging on the rising edge of the control
pulse and fire on the falling edge.  (or do they?  some sources seem to
indicate the the autodwell can delay or change firing so that it is not
always just the falling edge.  this sounded weird and I don't beleive it.)

Unquestionably, the coils have a built-in ignitor module.

Some sources say the coils are "smart coils" that control their own dwell
adaptively.

Some sources say the coils are psudo-smart coils that are only capable of
limiting how long they stay charged by automatically discharging after
100ms.

Some sources say "just feed them about 5ms of dwell and let them do their
thing.  drop pulse to fire"
Some sources say 4ms had less misfires than 3ms or 4 ms (
http://forum.aempower.com/forum/index.php/topic,774.15.html)  Many sources
seem to indicate that ignition module dwell timing control can produce power
gains, seeming to indicate that there is some manual control over dwell.

So, my questions:

1. Does anyone have a datasheet or pertinent technical literature from
Denso?
2. Does anyone know how much load the coils present on the logic side?  Is
it small enough to be directly driven by say a logic gate or would using a
small FET be necessary?  I'm trying to avoid propagation delays as much as
possible, and avoiding the prop delay of an extra transistor would be nice.
3. Does anyone have a definitive answer on how much dwell to feed these
coils, or how the dwell control works?

Thanks in advance,
-Dave