Omega type W ignition Dual plugging...coils, ohms?

[mattcfish]

Dual Plugging
Just for the sake of it:
Performance limits of the OMEGA W: 12V and 1.8Ohm primary resistance or higher (I wouldn't go as low as 1.8Ohm in such a risky application, think 3Ohm ... but even then!)
Two 6V coils connected in series: R1 + R2, each coil requires 6V supply, so you need to apply 12V (may work if R1+R2 larger than 3Ohm)
Two equal 12V coils connected in parallel: 1/2 R (may work if R larger than 3Ohm but Back EMF might kill the amplifier before you know it)
Don't mix and match, "path of least resistance" applies it can create all sorts of performance issues.

.

Stephen,
I'm using the Omega type W dual plug amplifier (I wish I had ordered the V as I no longer use points as a back up), so, according to the literature my dual output 2.2 ohm grey coils should be good if wired as directed, right? That's a total of 4.4 ohms. That's what the amplifier is designed to handle.
If I had a set of 1.5ohm Dyna Brown coils that would equal a total of 3 ohms. Wouldn't that be ideal? If not, what is the ideal coil configuration for an Omega type W dual plug ignition?
Is there a problem with Omega dual plug amplifiers burning out, even when wired properly? Why all the words of caution?
All of the Dyna dual coils are rated as 12V coils. My understanding is that that's 6V per outlet. So two 12V dual outlet coils is like having four 6V single coils.

[George Ryals]

The caution about too low of prmary resistance is to prevent the primary side of the coil from drawing more current than the amplifier is designed to control. 6 V coils and 12 V coils have an output (the tower(s)) of 35,000 to 40,000 volts when the electromagnetic field of the primary winding collapses, not 1/2 of the primary voltage.
Most electronic ignition systems are controlled dwell systems, meaning that the time 12 v is applied to the primary is controlled electronically instead of by the cam operating a set of points. Controlled dwell systems allow high current(low primary resistance...less than 2 ohms) for a short amount of time to build magnetic field quickly. Points operated battery and coil systems usually have voltage on the primary for a longer period of time (dwell), so use coils with higher resistance primarys ( 3 ohms and higher). Both types of coils, low and high ohm primary, have esswntially the same output to fire the spark plug, in the 35,000 to 40,000 volts. In other words choose the coils recommended by the system manufacturer.

[mattcfish]

The caution about too low of prmary resistance is to prevent the primary side of the coil from drawing more current than the amplifier is designed to control. 6 V coils and 12 V coils have an output (the tower(s)) of 35,000 to 40,000 volts when the electromagnetic field of the primary winding collapses, not 1/2 of the primary voltage.
Most electronic ignition systems are controlled dwell systems, meaning that the time 12 v is applied to the primary is controlled electronically instead of by the cam operating a set of points. Controlled dwell systems allow high current(low primary resistance...less than 2 ohms) for a short amount of time to build magnetic field quickly. Points operated battery and coil systems usually have voltage on the primary for a longer period of time (dwell), so use coils with higher resistance primarys ( 3 ohms and higher). Both types of coils, low and high ohm primary, have esswntially the same output to fire the spark plug, in the 35,000 to 40,000 volts. In other words choose the coils recommended by the system manufacturer.

So in this case, two 1.5 ohm dual output coils would be ideal?
The only coil that Omega recommends (on the Canadian site) for the type W dual plug ignitions is:
"Honda Goldwing Dual Coil pn #30500-422-003
(use OMEGA Type W)
~2.1 Ohm, 46mm dia (also a good alternative for dual-plugged bikes)"

[StephenB]

Matt, the danger is not the 1.5Ohm vs 2.2Ohm coils in series to make it 3 or 4.4Ohm, mathematically that is fine provided the dual coils are rated for 6V! I am quoting that part of my original response that talks about Back EMF being the unknown in this equation and THE potential killer of your amplifier:

... the "Ohms" is only one part of the equation, there are also "Henry's" and "Farrad's" that add to it. The Back EMF that the author above was talking about is a function of all three, Ohm Resistance, Inductance and Capacitance. When the coil is fired it creates an Electro-Magnetic Force (EMF) that induce a voltage back on the primary side (hence Back EMF) through to your amplifier. That is the danger with too many coils in series. It's like the kickback of a rifle.

The brown Dyna dual coil (part #DC2-1) is supposedly rated 6V/1.5Ohm and thus, would be suitable for the dual-plug application. The red dual coil is rated at 12V/1.5 and the grey is rated 12V/2.2Ohm. Those two (the red or the grey) won't work. You should check with Dyna which ones are 6V and can be wired in series for a 12V application.

[StephenB]

I'm using the Omega type W dual plug amplifier ...

Do you have 2 outputs Z1 and Z2 on your amplifier? If you only have one output Z then you have the single plug version (which I think you have) that you are now intending to use on a dual plugged bike to drive two dual tower coils (or 4 single tower coils for that matter). Everything I quoted and stated was based on that assumption.

You might want to clarify that because it makes a considerable difference

[mattcfish]

I'm using the Omega type W dual plug amplifier ...

Do you have 2 outputs Z1 and Z2 on your amplifier? If you only have one output Z then you have the single plug version (which I think you have) that you are now intending to use on a dual plugged bike to drive two dual tower coils (or 4 single tower coils for that matter). Everything I quoted and stated was based on that assumption.

You might want to clarify that because it makes a considerable difference

I had a Z1 that I originally purchased from you, but I've purchased a Z2 so I'm ready to dual plug. After reading this link http://www.bcae1.com/srsparll.htm
which puts everything in "electronics for dummys" terms (they even include a calculator), my confusion has actually increased some. The Omega ignition is supposed to wire up as a parallel circuit...right? If you have two resisters on a parallel circuit you take the resistance of one of them and divide it by the total number of resisters, in this case 2. Two 1.5 ohm brown coils would = .75ohms total resistance. That's way lower than the 1.8ohms minimum stated by Omega. What am I missing here? Seems like I need two 4ohm or higher 6V dual coils. Do they exist? Maybe I'm just getting the translation wrong....when Omega states "1.8ohms to 5.0 ohms" or higher resistance are they talking about each coil or total resistance?

[StephenB]

Ok, you have the W Dual. The rating is "per output". The outputs Z1 and Z2 are operating independant of each other.

Use two grey 2.2Ohm dual coils, one on each output Z1 and Z2. And that's it! No woorries about anything as the W Dual is designed for exactly that. I have emailed you the OMEGA manual for dual-plug installation.

The wiring examples that you have seen most likely refer to amplifier with only one output and then it can get tricky.

[mattcfish]

Ok, you have the W Dual. The rating is "per output". The outputs Z1 and Z2 are operating independant of each other.

Use two grey 2.2Ohm dual coils, one on each output Z1 and Z2. And that's it! No woorries about anything as the W Dual is designed for exactly that. I have emailed you the OMEGA manual for dual-plug installation.

The wiring examples that you have seen most likely refer to amplifier with only one output and then it can get tricky.

But the Greys are 12V coils....right? Or does that mean they are 6V x2. That's the way I used to think it went but more knowledge has only confused me further.

[StephenB]

The outputs Z1 and Z2 are rated at 12V with an resistance upwards of 1.8Ohm. The coil is rated 2.2Ohm @ 12V. The internal wiring doesn't matter as Z1 resp. Z2 only see resistance of 2.2Ohm.

[mattcfish]

The outputs Z1 and Z2 are rated at 12V with an resistance upwards of 1.8Ohm. The coil is rated 2.2Ohm @ 12V. The internal wiring doesn't matter as Z1 resp. Z2 only see resistance of 2.2Ohm.

Thanks Stephen, for your knowledge and time. I was beginning to think I would need to get the brown 6 volt 1.5ohm duals and put ballast resisters on them or something.
If you think the 12volt 2.2ohm grey coils will work I'll take your word for it. So the wording of the Omega sheet is a little off. 1.8 to 5.0 ohms (type W) is per coil not total. Total resistance in this case will be 1.1ohms (two 12 volt 2.2ohm dual output coils) according to the parallel circuit formula. R total=R1/# of resistors or 1.1=2.2/2