dual plug wiring diagram

[craigory]

Hey. Anyone got a wiring diagram for a dual plug 4 cylinder setup??

Can I just y- split the wires to the coil pack and run two?

Or will I have to run two complete edis4 systems side by side?
How would this be wired? Vr sensor, pip and saw etc....?

Any help would be great!

Cheers

[seishuku]

One waste spark coil per cylinder would work, otherwise I wouldn't even bother with the dual plug... Just plug one hole and use the other.

[craigory]

Would you consider a dual spark setup a waste of time? ?

Surely it has some sort of actual benefits?

[racingmini_mtl]

One waste spark coil per cylinder would work...

No it would not. That's not how wasted spark coils work: they need a wasted spark.

Jean

[old guy]

What kind of engine is it? How was the stock ignition configured.
There are a couple of reasons to run two plugs. Some of them were used as a band aid to meet emission standards.
Another is on engines such as a Hemi which usually has a pretty high piston dome to get any compression.
If they have the plug on one side of the combustion chamber the flame front has to travel around the dome, so they get pretty poor combustion. Put a plug on the other side, start another flame front and work toward the middle and more complete combustion=more horse power.
Usually when you convert to a two plug head you back the timing back up to 5 deg.
On some of the emission setups I think they even had different timing on each set of plugs.
Thats why it would be good to know what your stock ignition did.

[dontz125]

One waste spark coil per cylinder would work

It *might* work, but you'd almost certainly have two fairly weak sparks, and any fouling on either plug would immediately snuff out both.

A wasted spark arrangement is meant to work with one plug in a cyl full of cold, fresh mix (hard to spark; takes a lot of volts and energy) and the other in a cyl full of superheated ionised combustion products (easy to spark - basically a gaseous conductor).

You'd be better off with two logic coils, both driven off the same signal (a TC4427 or similar driver would DEFINITELY be a good idea).

[craigory]

Im building a 2.3 ford with forged pistons and a dual plug ford ranger head.
Intending on running a higher CR and a supercharger.
The ranger ran the dis system but I haven't got any of the wiring or loom.
Would a dual plug system be less prone to detonation?

One waste spark coil per cylinder would work

It *might* work, but you'd almost certainly have two fairly weak sparks, and any fouling on either plug would immediately snuff out both.

A wasted spark arrangement is meant to work with one plug in a cyl full of cold, fresh mix (hard to spark; takes a lot of volts and energy) and the other in a cyl full of superheated ionised combustion products (easy to spark - basically a gaseous conductor).

You'd be better off with two logic coils, both driven off the same signal (a TC4427 or similar driver would DEFINITELY be a good idea).

Forgive my ignorance on the "should work" idea, but do you mean y splitting a ht lead to both plugs?

Can you elaborate on the logic coil idea please?

[dontz125]

Seishuku was talking about using a 'wasted spark' coil to fire both plugs in one cyl using one signal. These coils are typically double ended, in that there is a HT lead coming off both ends of the coil. The HT circuit does not have a separate ground, as the current flows through one HT lead to one sparkplug, across the gap, through the head, across the second plug's gap, through the second plug, through the second wire, and back to the coil. As I mentioned, this really does require that one of the gaps be in an ionized, very-low resistance environment. Having both plugs in cold, fresh mix won't work well if at all.

A double-plug MIGHT be more resistant to detonation if the form of the chamber made it prone to det, like the high-dome pistons & head mentioned above by old guy.

A logic coil is a 3- or 4-pin device that has a built-in coil driver; the only signal it gets from the ECU is a 5v 'logic level' pulse telling it when to start charging, and when to fire. Since all the high-current wiring is internal, lighter wires are used. The GM LS1 and LS2 coils are popular choices for conversions, as are VAG coils.