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Discussion Starter · #1 ·
as some of you may be aware ive been working on a COP driver/splitter that will work on the KL engine, using either stock or aftermarket engine management (as it will divide one output into 6 coils).

so far ive had a lot of obstacles to overcome but heres an old pic of the prototype layout:
http://members.optusnet.com.au/dstojko/cop3.JPG

the smaller left PCB is an electronic latch, to prevent firing before knowing which is cyl#1 i have to wait for the hall effect sensor to tell me. obviously firing before knowing which cyl is which would be bad :jump:.

the main middle PCB is the divider circuit that separates the one ECU output into 6 individual channels, obviously this needs to happen quickly and reliably so i have some things to add to the circuit to ensure it cant fail and fire the wrong cyl. it also has a latched error LED where if something does go wrong it will let me know, e.g. 7 ECU pulses before its reset to cyl#1. on that it "sync's" every rotation so if something does happen once it should reset quickly (if i ever put this on my car it has to be perfect, im not blowing my engine over it).

the board on the right is the driver PCB which drives each coil. basically because of the design i dont know when the ECU is going to fire so i cant apply any dwell (charge time) to the coils, this means the only option is CDI (capacitive discharge ignition) luckily i have MSD already, so the board is supposed to separate the MSD pulse to each of the 6 coils through a transistor/SCR/RGBT or whatever can take it.

the only inputs to the board is
- 12v
- gnd
- ECU ignition output
- hall effect sensor 1 (cyl#1 TDC indicator)
- hall effect sensor 2 (each cyl indicator)

so far the problems im having while testing the board on the car is the noise from the spark plug leads is putting noise on the circuit and causing intermittent problems, this can be rectified easily as there will be no leads and it will be in a earthed metal box when done.

the other problem im having is finding a component to switch the coils in to take the pulse of the CDI, i originally used a SCR as shown in the pic (which is an awesome component for this but unfortunately it latches) meaning its great for driving low current stuff like the LED on the board but SCR's have a latching current where once the input is removed they stay on meaning all coils would receive the CDI pulse.

basically im posting this to get some feedback and ideas, i know theres not many electronics tinkerers on here but and comments/feedback would be handy.

im also interested to know if there is any other systems out there that split one ECU output into 6 channels. also thanks go to KLZE_Porsche who got me started on this, dont worry Porsche! one day ill have it running.
 
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I have a limited knowledge of electronics but i am working on that :p dad is a sparky and i have some friends doing electrical engineering at uni so i will have a talk to them, i will try to help anyway i can :tup:

Edit: is it possible to get Circuit diagrams?
 

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Discussion Starter · #3 ·
cant really provide a circuit diagram as of yet as most of it was designed on napkins and in my head then assembled so while i have got some hard notes you wont see the complete thing and id rather keep it that way as i dont want people stealing my work (not saying you will but someone might).

to further assist in this topic here is the MSD6A wiring diagrams and info:
http://www.not2fast.com/ignition/msd_6a.pdf

looking at page 15 is whats relevant to me, from my understanding C15 is the 1uF cap they discharge using SCR1. when SCR1 turns on it puts the +ve side of the capacitor (C15) to ground potential therefore the output (coil + wire) goes -ve with respect to ground as confirmed by whats said on page 8, now, i basically need something that will switch on allowing -ve voltage with respect to ground.
 

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