After another failed attempt to get my car to behave on the dyno today, I'm in the process of setting up a waste spark coil on plug ignition system on my car using GD coils.
There's a couple of things to be aware of.....
The 99-00 wiring harness has the following colours at the coil pack plug (engine harness side):
Black= 12v+
Red/yellow trace = cyl 1 & 2 trigger
Blue = Cyl 3 & 4 trigger
Blue / black trace = Coil ground
Interfacing to the Oem coil pack pig tail (cut off the old coil pack itself) the resultant wiring is:
Black.......... -=becomes=-........Red/ Yellow = 12v+ to coils
Red/yellow....-=becomes=-........Yellow = cyl 1 & 2 trigger
Blue.............-==STAYS!==-......Blue = cyl 3 & 4 trigger
blue/ black....-=becomes=-........black = coil earth
So.... seeing as GC8's only have 2 ignition channels & I need to fire 4 coils (wasted spark)...We need to make up a harness.
To fire the coils in pairs I made up two 'Y' harnesses to fire opposing coils (1 & 2 off the yellow wire, 3 & 4 off the blue), in pairs .
Notes:
Coil Power: All four coils are fed 12v+ from the red/yellow wire (which is powered off the fuel pump relay).
Coil Primary Earthing:You can earth the coils individually through their mounting bolt (not a necessity - if using the factory harness).
I used 5 core shielded wire to make the coil harnesses.....Be sure to use cable thick enough to prevent voltage drop at the coils.
I've taken some pic's & I'll post them up once I have everything tidied up under the bonnet.
Thanks to Prototype Rob for the GD coils & coil sub harnesses.
This mod fixed all of my ignition issues - I'm currently (June, 2015) running E85 @ 1.6 bar on a TD05/20G on standard plug gaps with zero issues.