From what I remember, if you rip open the Miata's harness a few inches back from the coil connectors, it used a #12 or #14 (Blue). In no way was it a #16 or #18 feeding the factory coils. I'll have to go look now. I may have used a #14 for power and ground in the cop harness. =)

The AWG table posted above states:

#18 - 2.3a - 6.385ohm/1000ft
#16 - 3.7a - 4.016ohm/1000ft
#14 - 5.9a - 2.525ohm/1000ft
#12 - 9.3a - 1.588ohm/1000ft

Their description of chassis wiring is: "Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle."

I can see at high RPM one of these coils pulling ~2a easy. x4 = ~8amps. A #18 is clearly undersized in this example. If I have time I'll test a coil at '8000rpm' and see what it pulls. I will account for compression as well. (66hz sequential or 132hz wasted spark)

Anyone ever look at a s2000 COP to see if it has the right dimensions and inputs/dwells are reasonable for hooking up to a Miata?

Most of the cop coils with an internal ignitor will have similar dwell so they could work. May not as common as the Toyotas. Do other Hondas besides the s2000 coils use the s2000's engine? The Toyota 1ZZFE is found in '00-'06 Toyota Celica GT, Corolla, MR2, Matrix, Pontiac Vibe and probably others.

Not sure about what might else use the engine. Someone asked me about it and I figured this was the place to ask before trying to dig up some tech specs on the COPs (no luck with google yet). The Toyota coils make sense for a lot of reasons.

Score

Loews had a metal strap 1.5 inches wide and 22 inches long. I'm gonna cut it down and use it for my COP bracket. It should turn out better then the 22 gauge metal sheet I got from home depot. Ill post pics tomorrow of the outcome.

http://i27.tinypic.com/28uqmh.jpg

It's only a matter of time before the handcream jokes start rolling in.

For what it's worth. s2000 coils are:

Pin 1 - Trigger
Pin 2 - Ground
Pin 3 - Power

There isn't a tach output.

All 4 coils are fed V+ through a 15amp fuse.

Yea, saw that after I posted. I have really dry hands ;)

Result:

http://i25.tinypic.com/14nskk.jpg

Cost = $5 with nuts and bolts.

That #4 coil should line up with the valve cover bolt ?? I just used a spacer and a longer bolt on mine.

yeah - I did the same with mine - it lines up well enough. 75 mm bolt I think, and it was a slam dunk, with a short spacer.

Today I got a coil (two) in the mail which I bought as spares, but they have a different angle. The hole is straight off the back of the coil (though offset slightly) instead of on the side. Functionally the same I imagine, but a different packaging. Pretty interesting, I don't know what thye are off of, but they look identical to the other COP from toyota aside form it. Pics if people want them tomorrow.

Pics and part number. There are at least 4 different part numbers for Toyota cop coils. I haven't seen a side by side comparison yet to know the difference.

its the same coils for corolla, celica, MRS, Matrix...same motor in all
the coils are app specific due to those mounting holes only...

I didnt want to disturb the valve cover bolts. I figured they are there to hold it down and a longer bolt wouldnt let me secure it well enough. Besides, I doubt whoever looks under my hood is gonna go "nice turbo, oh and one of your coils isnt straight".

Sam, what's your strategy for the wiring harness?

I got the toyota connectors on the way, I got braineacks letter with the contacts and I have weatherpack plugs sitting on my desk.

Its the more expensive approach but I do it once and do it right.

I also got bored tonight and painted my bracket.
http://i27.tinypic.com/9igvf9.jpg

'straight style' 90080-19023 coils
 

"one" of mine isn't straight. They all are the same. It works out well. I just drilled and tapped the plate so it sits flush, instead of needing nuts or screws from the back or anything. I just twirl out a 10mm cam-cap bolt and the coils come off. Except the one in the back, I used the longer bolt and a spacer, and it's probably the best held down part of the entire valve cover.
http://abefm.smugmug.com/photos/258959385_UphCw-L.jpg
http://abefm.smugmug.com/photos/258959336_SctEu-L.jpg
http://abefm.smugmug.com/photos/258959423_HETZX-L.jpg

And this is the "regular" style on my car, as installed now:
http://abefm.smugmug.com/photos/258961640_RqsoE-L-0.jpg
http://abefm.smugmug.com/photos/258961724_9V2mm-L-0.jpg

To do it the way I did, the tolerances on where you drill the holes are relatively tight, but not unmanagable.

If I had 4 of this "new" straight coil, I would have all the bolts in the front, and the plugs in the rear, I think it would look good.

So you are going to install a weatherpack connector before the factory coil harnesses and then install 2 mating connectors (factory coils and COPs) so that you can swap between the 2?

Exactly. So if we could gather each part number and pics of the corresponding coils it could be beneficial to have that all sorted out. The '01 valve cover I'll be using might be better off with straights, or maybe angled? I don't know yet. There's alot of crap in my way on that valve cover that limits where I can weld on bungs.

i think the collection of part numbers has already been started in the sticky version of the COPs how-to
mine are angled, and the part number is already listed, so people with the less commong COPs need to step up and list their part numbers so we can differentiate

Yes. I am going to chop off the factory harness and put a weather pack on it, the factory coils, and the COP's. I will pull the factory coils out though, I just wanted the ability to swap between them quickly if I ever have too.

Hey Abe, question. Did you JBWeld nuts under your plate so the bolts have something to thread into?