Can it be done? I was thinking that this may be a really cheep way of making a COP set up for a 4 cylinder.
The plan:
Mount 36-1 gear in the cam. Because the cam is spinning at half the crank speed it would cause the EDIS to only initiate a spark once for every coil connection for every 720 deg of crank rotation. This in effect eliminates the wast spark. I would plan on having it fire COP units from a ford 4.6 V8.
Things I don't know / Things that get weird:
It would see RPMs at 1/2 the motor speed.
Timing: Since the cam rotates half as much as the crank I would assume I would need only half the timing when tuning. IE 10 deg btdc on the crank is only 5 deg on the cam. This would mean I could (in theory) put in or pull twice the crank timing as the EDIS timing normally would allow.
The default limp home mode would be 20 deg instead of 10. What would this do?
Any thoughts? Ya I know I am nuts but it seems like it may work.
Nothing wrong with a waste spark coil on plug. It lets you use 2 channels instead of 4 on a 4 cylinder.
I know that but I think it would / will be easier to mount the 36-1 wheel and sensor on the cam then on the crank. And I have a bunch of the COP coils hanging around as spares for my Expedition. (seven to be exact) since I only need 1-2 as spares for he truck that leaves 5-6 to play with.
I am doing this on a 2.5l water-cooled Porsche motor (in my 924s) Going to a EDIS system would eliminate the dam speed and reference sensors (that need replacement in my car s there is a loose connection in one of them that is a PITA) at well over $75 each for the BMW equivalent I am very close to the cost of an EDIS conversion. The whole COP thing is just me thinking. Besides it would be really cool!! I am just wondering what I am not thinking of that would make it not work.
I already have the 36-1 wheel and the pickup form a motor swap. I have the coils. I can get an EDIS-8 unit cheep form the junk yard. Then all I need is a spark controller. Ether MS or the meggajolt setup.
I don't see why this can't be done if you have enough room for the trigger wheel, but as you noted the timing table would be skewed. I would set up the sensor so you still have 10 degrees limp-home timing; setting it so you get 20 degrees will give you an even weirder timing table.
If I were doing this myself, and had to put the wheel on the cam, I would simply have the Megasquirt read the sensor directly and put four coil drivers in it. This would give a normal timing table and it's a few less components.
It comes down to what is the least expensive controller I can get. I really like the MS idea and then there is the megajolt. I am not sure of the costs but I would really like to keep the controller price to $100+/- if possible. Ya I know I am probably dreaming but it would make the conversion roughly equal to changing out the speed and reference sensors and eliminate the bane of the 944 owners existance... well maybe next to the timing belts and the DME relay.
Is there a $100+/- programmable ignition controller out there?
