Quoting JNR:

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Thanks for the update and keep us posted on long term reliability and all that...

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The main reliability question for me was whether there might be issues associated with doubling up the transistor packs -- either at the packs or COP modules. However, the successful long term usage earlier suggests not. I've moved coil power completely out of the OE harness and with the heavier shorter wiring, there ought to be greater spark energy, so my main concern is operating temps. The heat sink assembly is clearly keeping transistor temps well down, but I still have to verify the COP module temps are also fine. With the aid of the small air gap around the COP plate, I'm not expecting an issue.

That leaves two things that are new -- the COP capacitor and the relay. The capacitor is located under the COP plate adjacent the timing cover. This puts it fairly near the rear cable opening and there's an air gap around the edge of the COP plate. Plus, the mounting tab serves as a heat sink and is bolted to the valve cover. In addition, it's designed for automotive use and as I recall, it's rated for 120C. I don't think it should be a problem.

So, that leaves the relay and it has six things going for it.
*It's rated for 40A and is probably carrying under 15A peak (line fuse is 15A)
*The only load it sees on closing is a .47uF capacitor (safe for the contacts)
*It takes about 14msec to open and coil load should have ceased (safe for the contacts)
*It's located in a fairly cool area of the engine bay -- low behind the plenum
*Its temperature rating is 40-125C, and its cycle rating is 100,000 at 40A
*I sealed its case to protect it from vapors or gases in the engine bay

So, the only downside I currently see is there's a new load on the battery with the ignition ON. The relay coil draws around 140mA at 12V -- well, we're not really supposed to leave the ignition ON without the engine running ! If I can get a scope on the coil battery line I should be able to learn more about load behavior.

Quoting TrevorS:

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If I can get a scope on the coil battery line I should be able to learn more about load behavior.

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Installed my curent sampling resistance at the relay today and idled the engine while trying to take measurements (the mosquietoes loved it ).



I tried two different scopes and ran into anomalies with both, but finally came up with what appear good and reasonably consistent data. From the waveform, it was clearly not reaching coil saturation, though the charge time was aprox 8ms with aprox 96msec between individual coil charge cycles. That translates into 625rpm which roughly agrees with my dash tach. I measured a peak current of about 12.5A using the above .02 ohm sampling resistance, which translates into 3W peak on a wire-wound resistance rated at 25W and operating at a roughly 8% duty cycle -- don't think resistance heating should be a factor. Looking at the battery side of the resistance at same sensitivity (.005V/div) I was seeing only transients, no noticeable level shifts. By the time I completed these measurements, the engine had been idling for quite awhile and I doubt the battery voltage was higher than 12V, 14V would make a difference.

Since the coils didn't reach saturation, I can't be sure what the true peak current would be, but with 14V the current would increase by about 2.5A and judging by the shape of the charge waveform, the true peak is likely on the order of 18A. Perhaps that would achieve saturation, but I doubt 4ms could do it. Thinking of fusing, at 6Krpm individual coil charge cycles occur every 10ms and coil duty cycle could be similar to 60%, but there won't be time for the current to climb (suppose a worst case of perhaps 15A @14V, 60% would be under 10A average) and so I expect my 15A fuse is fine. Regarding COP module heating, looks like they're unlikely to actually saturate and so resistive heating should be minimized, but there's still laminate heating (particularly at higher duty cycles). However, given the Intrepid operates the COP modules independently, they each see battery voltage (with at least .4 ohm less series resistance) whereas ours share it, and so I'm guessing their higher current heating is likely similar to our waste spark double duty-cycle heating -- probably not an issue.

Quoting broxma:

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we did dyno the car up to 362 WHP using the dual ignitor setup. The car was boost limited as in it had a massive crack in the intake manifold which prevented the car from seeing more than 18 pounds, but the ignition system performed flawlessly.

<snip>

I'm glad to see this thread is still alive. Several of us put a lot of effort into testing and designing this stuff, and I hope in the long run it helps out more than just the few of us who started looking into it. That appears to be the case so I'm glad to have contributed.

/brox

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Thanks for dropping by again Brox and that's too bad about the Galant, but it's pretty clear you have lofty targets ! Very interested in how things go with the Nissan and the dual ignitor COP ignition, keep in touch! Hopefully others will jump in here too.

Quoting Broxma:

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To ride along with one of the things you mentioned in the last post, about the way the Intrepid coils each see battery voltage...

One of the changes I am going to do to the setup I run on the Nissan is run the power wire off a relay. Since the positive wire at the harness is always hot, I plan on running it to a 30A relay instead of running the coils off power supplied by the ECU. The ECU is getting all new wires, all new pins, so I'm increasing the wire size on both the positive and negative of the ignition.

I also may not go with intrepid coils.

/brox

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In case this info is of any use to you:

1) I ran 10 AWG (starting with a fuse holder) from the battery to the relay following the existing firewall harness.
2) I ran 12 AWG from the relay to the coil connector.
3) I ran 14 AWG from the coil connector to the COP module +12V terminals.
4) I also ran 14 AWG from the #1 to #4 COP modules (a relatively long run).
5) Remaining COP wiring between ignitors and coils are OE 16 AWG and similar total length. (Charge waveform is also similar height.)
6) Ignitor ground is 16 AWG each to a stubby 14 AWG to a nearby ground bolt.

Given the peak primary current might reach 18A, I'm considering changing the 16 AWG dual ignitor to COP coil module wiring to 14 AWG, but that may be going a little over the top for my purposes -- having difficulty deciding ! Would love to know what you come up with, and whatever measurements you make ! (Including the COP modules!)

Quoting TrevorS:

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Took the car for a run and then measured the COP module temps. Coil 120F, COP plate 140F, valve cover 170F, outside ambient 85F. Typical COP temp rating seems to be 120C (248F), so I think the COP margin should be fine. However, I notice the battery is discharging faster than normal at idle. Thinking of backing off the primary current a little by returning the transistor pack ground to the harness.

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Quoting TrevorS:

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Replaced the cracked rear transistor pack connector and returned the ignition transistor pack ground to the harness. Still draws more current at idle than OE (guess not a huge surprise), but not as bad as before. Got to scope it to see where I'm at!

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Quoting broxma:

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The interesting aspect of my build is that it will be running on the exact same Evo 8 AEM EMS that my Galant was running on. Incidentally, the ignition system on the KA, although it normally uses an old style distributor, the was made by non other than Mitsubishi. If you remove the cap, rotor and inner cover, you find an optical cam angle sensor. It happens to be the exact same cam angle sensor as a 1st gen green top CAS. You can simply replace the optical wheel with either a 24 tooth or stock 1G CAS wheel, and any Evo 8 designed ECU will work just like factory, provided you do some wiring. This means the same ignition principles we worked on here, will transfer over directly to the Nissan.

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