Best Advice on Direct coil driving?

[R100RT]

To avoid falling prey to the category of one who doesn't read any posts, as well is not building anything - please acept my humble appologizes for getting stumped on the indicated question - however I am a dedicated participant, have about 90% of the project completed which is:
"1983 BMW R100RT bike being turboed, injected, photo's will accompany that point in the project that she's out of the workshop and into the garage again".
OK - so its not just a casual observer cluttering the post ways.
I observe pro's and con's relative to driving the ignition coil directly, or with external module, and fail to see the best percentage.
One post will say it is definately worth "not doing" , another claims it is part of the micro squirt and works just fine. Then it is stated that the tach signal "interruptions" occur within the box and this causes one to ponder if the interruption develops on the external wiring and chases inside, or takes place within "despite your best house/keeping efforts" at properly sheilded and separated wiring.

If I could gain clarity on the two methods in the following questions:

WHEN YOU DIRECTLY DRIVE COIL(S):
-The capacitors mentioned (0.01microFarad @ 630v etc.) are giving me a bit of challenge to locate exactly and I tend to frequent the automotive supply stores more than electronic supply houses so , can I just use one of the old Ketering or points style of capacitors instead? (3.0ohm dual output "Dynatek Green" coil presently on the project).

WHEN YOU DRIVE WITH EXTERNAL MODULE:
-Sounds like changes are required for the Micro Squirt such as either
a) "Logic Level Signal" modification by removal of the VB921's and adding the appropriate Bosch type module.
or
b) Addition of the 4.7k resistor from Vref to IGN output -HVc, etc.

I see significant factors on each side of the fence, I'd be obligated in a serious way if Squirters that have "been here & done that" before might post a comment to help aid in this decision.
Thanks in advance, any comment valued.

[R100RT]

Well, here's a reponse to myself then, the simplistic approach might be then to attempt direct coil driving while following all the recomendations listed (and I appreciate some of the earlier posts whereby I note a lot of work by the product founders and others).
During start up/ set up what will be the difference if some add on's are required at that point to address problems that may/may not occur with noise.
I note some of the latest M.S. have a jumper fixture within to handle the choice to go with logic level output, nice touch.

[RedRocketRally]

That's the approach I took. I figured I'd try it with the internal drivers, and if it didn't work I'd add some externals. I followed all of the recommendations. Its working well so far.

My ignition wires are separated from the microsquirt harness, and wrapped with a few strands from a stripped speaker wire, then wrapped with a few layers of aluminum foil. I tied the bare wire to one of the unused ground pins of the relay board DB-37 (somewhere along the top row) to ground the shield. The VR sensor also goes back through its shielded cable. So far microsquirt gets a good signal from the crank wheel trigger.

I didn't connect the ignition wires through the relay board. I believe one of the diagrams in the manual suggests using the spare outputs on the relay board (S1-S5), but I followed the suggestions on the dual-spark page and kept the ignition wires separate and connect them through a 2-wire trailer connector directly to the coilpack. That way I can get the ignition wires as far away from everything else as possible, starting right where they come out of the microsquirt. I left a few feet of slack on the wires between the trailer connector and the coils so I could move them around, or even pull them through a different hole in the firewall if necessary (so far it isn't).

The injector wires are shielded in foil the same way between the microsquirt and the relay board, but they are bundled with the other wires inside the convolute.

When I hooked everything to the relay board, I left some slack in the wires to the injectors and a few of the sensors. When I see noise I have freedom to move things around and re-route to eliminate the problems. Once everything is happy I'll cut them to an appropriate length and zip-tie everything in place.

As far as spotting noise, Megatune and MegaLogViewer are a good start. When I first got everything running, I had a bad ground which showed up on all of the sensors in Megatune as jittery needles, even when the engine wasn't running. In MegaLogViewer I could see that all of the sensors jittered exactly the same way at exactly the same time, so a bad ground was the most likely suspect. Once I fixed it ( by moving the LC-1 heater ground from the sensor ground to a chassis ground), it all smoothed out.

I'm hoping to get the car drivable this week so I can get some miles on it and really work out the kinks before I button everything up. I'll get the interior and dash installed this week, a trip permit next week, and then I'll be driving it everywhere for at least three weeks. Maybe more if it passes DEQ

[R100RT]

Your feedback and info much appreciated. I'm making my own "relay board", on a bike format everything has had to fit in a suitable area so custom fit is best.
Good luck on your tuning

[65looter]

I'm going to try direct coil first, and if it doesn't work I will then use the EDIS module.

[R100RT]

So few posts here, I have to reply. I'll let you know of my results - trying to get things to the point of spark up but having family oblig. taking precidence. I have noted no interferrence during cranking cycles, that's perhaps the first step in the right direction.
What is your project?

[65looter]

my project is a Ford V8 342 (5.6L) in a 1965 Mustang
Microsquirt v2, auto-nomics throttle body, 4 injectors running fuel only for the moment. planning to go full EDIS or direct coil control.

[R100RT]

Started bike this weekend, I expected to have some issues with possible small leaks and other things that after a long season of modification will come up, but only encountered a defective ignition coil not firing one cylinder. I had purchased a "Dynatek" Green coil, tested dead on one outlet on the bench after pulling from bike.
Seeing my long weekend of set up and programming slipping away, I visited the local junk yard and picked up a coil only "EDIS4" pack (without module). Although I am not exactly sure how that coil wants to work, I only need two spark plugs worth of output. I tried driving it through "Ignition 2" on one outer terminal (coil pack has a 3 pin connector), the center being 12v + from ignition. That didn't seem a happy outworking so I routed "Ignition 1" out from the remaining M.S. wiring bundle and connected to the other outside coil pack pin. I have those other two spark plugs just hanging for now, bases grounded - that allows even firing on the bike. Perhaps someone has attempted a similar usage of one of the EDIS coil packs where they didn't need all of the outlets? Any feedback/ help appreciated.
Pretty unique sound on the old air head now, not even remotely similar to the revious melodic "thump - thump- thump" exhaust note.
Lorne

[SQLGUY]

I'm running an air-cooled inline 4 with a pair of GM Saturn DIS coils. I'm driving the coils directly from the Microsquirt VB921's. I bought some Panasonic supression caps from Digikey (a great place to deal with for electronic parts, including good prices on MPX4250's), but I've never gotten around to installing them, and I don't think I need them.

Anyway, I am using coax RG58 cable (CB radio cable) for the wiring from Microsquirt to the coils. The shield of this is grounded at the coil end of the run. I'm running about 3mS of dwell for these, and they work fine. Primaries are about .5 Ohm. You can check the dwell by checking the temp of the VB921's... if they start getting too hot to touch, you're overdwelling. Mine run just warm, not hot.

There's more detail on my project here, in case it's helpful to you: http://residentialcolorado.com/SECA_750i.htm

Cheers,
Paul

[R100RT]

You have a nice amount of work showing your project, as well as the handywork on the bike too! I haven't got to the point of putting pictures online, however a comment from my wife gave me the confirmation I was looking for - "What did you do, where are the new parts"?
Fitting everything adjacent to the BMW fairing was challenging, but pleasing now that its fit.
So, your ignition set up is very similar, except that you are using all four spark leads and I only need two of them. I'll probably chase down info on the Ford EDIS4 module to get an understanding of how to either turn off one coil, or route high tension leads to dummy plugs undercover. I didn't want to excavate the potting to get to the coil pack wiring if possible.
Lorne