3 wire COP vs 2 wire COp's to EDIS

[wca9922]

I am venturing to convert my setup from EDIS4 +HT leads to EDIS + COP setup.
Serching for the various types of COP's out there, I found that some COP's are 3 wire types ( eg late BMW's have 3 terminals - +12V/ Secondary Ground & Coil Driver). I have also seen some write-up of controlling this set-up with EDIS-4 driver and wiring in series.

On the other hand , I've seen 2 wire (+/-)COP's that are mostly found on Japanese performance bikes and cars and mostly are manufactured by Nippn Denso.

My questions are:

1) What is the primary design diff between 3-wire COP's and 2 wires? What is the additional +12 for or on the 2 wire COP's why is there no +12V source?

2) Using the EDIS-4 controller and eliminating the coilpack, which type of COP (using 2 wire COP or 3 wire COP) should i use in terms of simplicity and reliability?

I hope to hear some sucess stories of the EDIS+COP setup.

thanks

wca

[jsmcortina]

Some COPs are "logic level" and contain the coil driver (ignitor) these would be unsuitable for use with an EDIS module. Additionally many COP sticks are lower impedance than standard EDIS coils and put an additional load on the module which may damage it.

The "dumb" 3 wire COPs ought to work just as well (or badly) as the two wire.

Personally I would not use a COP coil with EDIS and would drive it with direct coil control instead because that way you can use one driver per coil and you have the opportunity to control the dwell.

James