I'm starting on a new project to attempt to build a Wasted Spark Ignition setup that will simply plug (add on) to the stock Motronic DME.
I'm in very early research stage and am looking for anyone with technical background of the Flywheel ref sensors. Also technical background of Ignition Coil Dwell times across the RPM range in the 3.2L.
At this time I'm just starting to look at the relationship between the TDC sensor signal and the Ignition Coil signal from the DME. I may also use the Speed Sensor signal but am hoping it's not needed.
The basic idea is to build a controller, simple set of circuits to convert the existing coil signal which fires 3 times per rev into 3 new signals to fire the 3 Wasted Spark coils.
I also think I'll control coil Dwell times from the new circuit as well.
But, I plan to fully honor the Ignition Maps in the stock DME. I have researched some other aftermarket systems but these want to take control of the timing tables away from the DME and I simply do not wish to do this. I only wish to remove the distributor and goto 3 double-ended coils. I also wish to control Dwell to optimize Dwell for the coils choicen.
Here is a timing diagram of the signals, the top 2 are existing signals available from the DME and the bottom 3 are the new generated signals.
At this time I'm only working on the Digital side of the controller to produce the new signals. Then later I need to design the hi-power section to drive the new coils but this should be easy, I plan to simply copy/follow the stock DME output stage for driving the stock coil, I'll replicate this output stage 3 times. The hard part is the early research for knowing how the 'TDC Ref signal', 'Stock Coil Signal' and possible the 'Speed Ref Signal' are all related. Also understanding how the Stock ignition dwell works would be helpful. Few things I don't know about Dwell is how long is the stock dwell in milliseconds (I can scope to get this) but more importantly does the stock system reduce dwell time at very hi-RPM? like above 5000RPMs. At hi-RPM it is often dificult to find enough time for optimal coil charge and some systems simply must comprimise and reduce dwell at hi-RPM. Does the Motronic system do this? Any help here would be great.
I'm a Electronic Engineer so I feel good about building the controller but I need to learn a bit more about the Stock Ignition and the signals that drive it. Any info here would be very helpful.
Lastly, this should not be a very expensive project. Parts for the controller should come in under $100.00, then you need the coils and wires.