Ignition transformers with logic inputs
Although GenBoard/VerThree has onboard IGBTs so any ignition transformer designed for inductive ignition can be hooked up directly (that has no drivers), in the future we'll also look at coils with builtin drivers. These usually need a proper input with dwell-control (that is no problem for GenBoard, of course), but have some protection so a spark is fired after some time if the input is activated for too long.
- traces - no HV traces onboard
- connector - no HV needed
- installer-friendly: less risk
- wiring: less power through the ECM (GND5)
- significantly lower electromagnetic radiation than the fast-changing big current through long wires: logic signal has negligible effect on trigger, nernst, EGT and other sensitive signals
- more on the above 2: GenBoard/Manual/GroundConnections
We must get a good supply of these items (driverless COP transformers also). Good supplychain is always a pain to acquire.
GM Opel coilpack == GM 4cyl wasted spark ignition amplifier
These are monoblock coils, epoxy filled. junkyard price is appr 45 Euro. In EU you find it in 1.6L F-Astra or G-Astra (or Vectra or other Opel or Vauxhall models). We don't have info on availability in US. However there is almost identical ignition module on Daewoo (eg. Kalos, Nubira) models with different (smaller, probably less common type) connector.
4 terminals JPT connector
- 1 Power
- 2 GND
- 3 black-red color, (cyl1,4)
- 4 black-yellow color, (cyl2,3)
With a running engine I could go down to dwell14=0b (700usec) when it loses it's power, but the horrible high cranking and afterstart pulsewidths demand high, dwell14>0x20 (rather >0x28) even though dwell6>90. I haven't fine-tuned it or verified power consumption yet.
Hard to miss by the lookout. Anyway, some numbers from my unit
- partnum: GM 1103872 1A23 (maybe just the cover plastic part?)
- backside number: 10487489 must be a part number, since I found a [part in a pdf list] (or [same in html] that claims to replace this
- 0D12 ???
Measurements - Experiments
After some unsuccessful spec-googling on the Opel (GM) active coilpack (came from my Opel engine), I decided to give experiment a try.
- wired up supply to GenBoard/VerThree
- wired supply to the ignition module
- shorted the cyl1-cyl4 HV pins with a little gap
- shorted the cyl2-cyl3 HV pins with a little gap
- pin1=VBATT (9V in my experiment)
- pin3=short 1.5 msec dwell applied by mdn01 => fired cyl1,4
- pin4=short 1.5 msec dwell applied by mdn01 => fired cyl2,3
I first connected pin3 only and than pin4 only (therefore the same mdn01 command for both output). The other one was left open, on the open input I measured 0V.
The pulse I applied was inverted with an ES2J (fast, 600V, SMB, same as used for flyback) diode and a 2k7 resistor pullup from 5V to the IGBT output (this makes it possible to use the same output for a raw transformer with max 7A and 380V). Pulse was about 4.5V for a short 1.5msec time, and normally 0.53V. To achieve this, I used ign_out=71 inverted semantics so the IGBT is switched on normally.
I asked my girlfriend to issue the mdn.. commands from the terminal running on the notebook (connected to GenBoard via USB-rs232), so I could watch which transformer-output fires on a given input.
Note that I'm not absolutely sure that sparks are emitted on the falling edge, but 99% sure at least.
This module looks more rugged than the Ford coilpacks (that has no driver inside). Strangely, the Ford coils seem to be more known in diy-land.
- Bigger transformers
- because of the internal drivers less electromagnetic radiation in the harness and
- less heat in the ECM box.
- It is even possible to use FETs instead of the IGBT (or even a P259 output) to drive it, so the IGBT insulation issue goes away too.
- Price is about the same (appr. 40 Euro for a used but good condition 4cyl wasted spark coilpack).
- Connector is nicer too
'''Note that this module fires properly driven from a weak logiclevel drive even with a 1k resistor (510 Ohm is standard now). Some active coils (VAG active COP coil was reported) needs 100 .. 270 Ohm, it just gives very weak spark from 510 Ohm.
- Specifications for GM DIS and HEI at  and .
- consider 4 IonSense compatible coils (small is enough for CDI)
- sparkplugs for turbo operation: I have no idea of type. I like the cylinder-symmetric ones (the type with a center electrode and 3 around it, used in Formula1, except with normal size thread), but not sure if it worths the extra cost and hunt. What heatrange should I use ?
- probably going wasted spark for now: (I don't have COP at the moment. appr. 69mm from COP coil bottom to sparkplug tip).