Hi there. I'm getting ready to run my megasquirt on a ford with coil over plugs. I'm wondering what type of internal schemanics a coil pack would have? I'm interested in 8 cyl.
AL
Ford coil pack internal structure?
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What are ya packin?
The dual plug coil packs used on the I4 and V8 Ford EDIS system consist of two "dual spark" coils. They are wired to a common positive pin, and have a separate ground pin for each coil primary winding for a total of three pins. The I4 uses one pack, the V8, two. When one of the two coil primaries is energized by grounding, that coil charges its magnetic field. When the ground is released, the field collapses and the secondary winding fires, causing a simultaneous spark in two complimentary cylinder spark plugs. Thus, there are a total of four coil towers, two for the first coil, and two for the second.
The conversion of the EDIS system to coil overs has long been discussed, but to the best of my knowledge, never tried. An 8 cylinder EDIS module will have four coil control lines, with each coil firing two spark plugs. Thus, you will have to wire two coils in parallel for each control line. The question has always been, Can the EDIS module drive two coil overs, without being overloaded? When you try it, if you find out it cannot, you will have to get a new EDIS, and build a simple power transistor driver circuit to handle the higher power.
Please keep us appraised of your progress.
The conversion of the EDIS system to coil overs has long been discussed, but to the best of my knowledge, never tried. An 8 cylinder EDIS module will have four coil control lines, with each coil firing two spark plugs. Thus, you will have to wire two coils in parallel for each control line. The question has always been, Can the EDIS module drive two coil overs, without being overloaded? When you try it, if you find out it cannot, you will have to get a new EDIS, and build a simple power transistor driver circuit to handle the higher power.
Please keep us appraised of your progress.
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Oliver Sedlacek
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Coil overs
The main problem is that the EDIS is a wasted spark system, which doesn't care which cycle a cylinder is on. It sparks the cylinder at the top of the compression stroke (thereby beginning the power stroke) and it also sparks at the top of the exhaust stroke. A coil over system must distinguish between these two cycles, which means that it needs a cam pickup instead (or as well as) a crank pickup.
Why did the coil over cross the road?
Although that is true if you wanted to fire the coil overs individually, it would be overly complex to try and switch the coil trigger line back and forth between the paired cylinders using a cam pickup and electronics. By firing both coils at once, the spirit of the EDIS is maintained, each time the two coil overs fire, one will be on the compression stroke, and the other will be on exhaust.
Why does coil over needs to
Why does coil over needs to distinguish that? What are the advantages of coil overs vs waste spark?