[dazq]

Individual coils can also be wired in pairs as wasted-spark, so the choices are endless. Here's an example of 6 passive (dumb) coils run on 3 channels as waste-spark we did years ago:


6-CYL_WASTE_SPARK_2_MODULES.png

Following on from David's suggestion above , you can use a 211 4ch Bosch module in place of the three channel type seen in the diagram. Just leave ch4 disconnected.
You may find the 211 type cheaper and easier to source than the 3ch type.

[MikkoR]

I think I'll choose a ready solution.
This might work?

https://www.ebay.com/itm/371131514966

[PSIG]

Sure. Speeduino can run almost any coils or ignition type, when set-up properly.

[MikkoR]

In this coil there should be the igniter included, so no further hardware needed?

[PSIG]

Yes. The "VR6" coil pack is popular, with wiring diagrams online.

[MikkoR]

Close enough?

https://photos.app.goo.gl/XCKwtJTJCfrXi1wj9

[PSIG]

My eyes have not been recently calibrated for measurements. But, that gap appears quite large. There are many different VR spec's and working ranges, and the specific wheel dimensions have a lot to do with that; but the majority I see are functional between 0.5mm and 2.0mm ( 0.02-0.08") clearance. They may be marginally functional closer or farther, but you'll have to test for that, and at speeds from cranking and up.

I would assume from your photo, that either the sensor shoulder can be trimmed, or the mount bolt holes slotted for adjustment. Some mounts are reversible, allowing spacer rings under the sensor shoulder to set the clearance. Use what works.

[MikkoR]

I checked the clearance with a feeler cauge, result 1,8mm. So it should be within tolerances.

How heat resistant these Speeduino units are? I think I'll move the battery from the engine compartment to trunk. It will give me some more space (and a bit better weight distribution too ). The battery location is just against the splash wall and would be quite ideal location for Speeduino and the coil pack. But, is it too hot location?

[PSIG]

Arduino typically has an 85°C/185°F rating, and other components on the board could be even lower, so the engine compartment is not suggested. Weather exposure can also be an issue, and while you can use a sealed case, that would trap electronics heat inside plus ambient heat. The ECM is also closer to primary noise sources. This just moves the battle to a new location. The general suggested answer is no. Even for motorcycles and similar, more remote from heat and EMR is generally better.

It is possible to create an unsealed case for ventilation, sealed board for weather, oil, dust and moisture, and vent from outside for cooling, but that's getting rather involved when you can put it in the cabin to avoid all those issues. Even a high-heat-rated ECM would be in my cabin just for those advantages.

Have I put a sealed board ECM in the engine compartment, connector down for drip-line, cooling air from behind the headlights, and covered with an open-bottom zip-lock bag for testing? Yes, and it worked, but I still suggest the cabin. Do your thing.

[MikkoR]

I'll receive the VAG coil plug within a day or two so I can start building the wiring loom. One question about the power. I haven't found a clear answer, but I think the Speeduino should be powered all the time and you just cut the power for injectors and for coil when shutting down the engine. Right?