GM SmartCoils on the LS-1 & soon others

[garfield at pilgrimhouse.com]

On Fri, 29 May 1998 14:40:10 -0400, "Gary Derian"
<gderian at cyberdrive.net> wrote:

>The new LS-1 Chevy engines have one coil per plug.  These may have an
>independant ground for the HV.
>Gary Derian <gderian at cybergate.net>

Oh Man, you don't know the half of it!! A guy in our Aviation group that
works in a GM lab sent me one of these off a decommissioned test
vehicle, and they are NOT mere IGN coils, they're complete single-coil
IGN "systems". They contain ALL the electronics for dwell control,
current limiting, etc etc. These coils are DIRECTLY run from the
ECM/PCM. There is NO module. They have 4 terminals (plus the HV
terminal, that uses these ratchet style terminals I was tellin bout
yesterday), two for Bat Gnd, and Bat +12V, and the other two are the
digital EST signal and it's low-noise gnd return. Not usable for ION as
a transformer-type coil, cuz you cain't get to either the primary or
secondary on these puppies, but still a VERY elegant setup, indeed.

That ain't all. The biggest shock is yet to come. Brace yerself. They're
actually CHEAP (and nice and light, too). I couldn't believe it when I
went to check them out further. The GM parts counter LIST price is $41
for each "smart coil", and EVEN the harness for tying four of them
together is reasonable, list price of $62. You get 4 connectors for the
4 coils, and another larger connector. Not a bad price for 4 GM
connectors and pigtails (if you decided you couldn't use the harness as
is), at the very least, and you might even be able to get the bigger
connector from Packard! The shorty coil wires (yes, these DON'T squat
ontop the coils) have them real nice connectors I mentioned, and they as
well are pretty reasonable, at $11 ea list. My GM pal who must remain
anonymous says you'll see these exact same LS-1 smartCoils appearing on
all the big block truck and bus engines next year! That's what my
samples came off of, NOT LS-1 engines. Heh.

If we find that ION works OK with inductive IGN spark durations, and
it's still a pain to find suitable regular transformer-type coils, the
existence of these nice smartCoils might just tip the balance in favor
of using HV diodes and attaching ION's circuit right after the coil. Not
the most elegant electrically, but all things considered, perhaps the
cleanest, lowest total parts count. Neat stuff coming available now. A
good time to be outNabout in the sandbox of eXperimental life, eh?

Gar