Wiring for aftermarket coils - guidance

The American · Postby **The American** » Mon Oct 26, 2020 6:24 pm

Hi All,

As part of the Black Rat's evolution, it will eventually need an upgraded spark solution. I think I will attempt to get the new engine to the stage of a run-in tune with the stock coils, so I don't have to trouble shoot modifications to yet another system in the car concurrently (given how many other things are being changed). Or, is it not that hard to do?

I'd like to use IGN1A coils, as they seem to be the bee's knees and seem comparable to LS coils in terms of price.

Does anyone have any suggestions for a good guide to assembling an coil loom?

greenMachine · Postby **greenMachine** » Mon Oct 26, 2020 9:42 pm

When I received my racecar's engine from the builder, it had no coils (by request). I sourced some Toyota COPS, we wired them into the engine harness to fire sequential, and delivered it to the tuner who then set up the tune accordingly. If you are using a tuner, that should be bread and butter for him, if not, you have the wrong tuner. I see no reason not to follow this path, do it once, do it right the first time. You will need data for your chosen coils for the tuner (I think), certainly the wiring diagram for them, although that is more for whoever is doing your harness.

The exception may be if you are pioneering a particular coil. LS coils are a well trodden path for high hp cars, unless there is a specific need I would stick to them, or any other proven product - pioneering usually comes with a price tag. :frown:

GR124 · Postby **GR124** » Tue Oct 27, 2020 8:35 am

I'm up to choosing a spark source for my build. I was looking at the R35 nissan , then I looked at Audi R8 red tops. After talking to an owner of a very fast (and well known) MX5 race car I went with the Toyota COP, (currently in the mail). I bought genuine Bosch BIC729.
Wiring details and the dwell times etc to enter into the ECU is easy to find.

ManiacLachy · Postby **ManiacLachy** » Tue Oct 27, 2020 10:11 am

I installed the Flow Force LS1 coil kit on my car on the weekend. Super super simple, plug and play, adjust some settings as detailed in the instructions and it fired right up. Currently in batch fire config, but I purchased the additional wiring to go to sequential.

Obviously it cost a little more than DIY, but for ease of install, while also providing a strong reliable spark, I don't think you can do better.

plohl · Postby **plohl** » Tue Oct 27, 2020 11:16 am

the best guide around is probably this one

https://www.miataturbo.net/useful-saved-posts-8/upgrading-coil-plugs-all-years-cop-writeup-12704/

Not 100% relevant because of different coils, but everything will be mostly similar.

If you're still keeping the standard loom and going to keep running wasted spark (1 ign signal fires 2 cylinders), I would suggest adding a connector in the current coil harness (pretty sure its 4 wires) whilst the engine is out. Just makes it an easier job.
A duestch DTM or DT connector would be suitable and they're easy to pin/de-pin. You need some special tools, but nothing super expensive.
Then you can keep running the standard loom and build a patch harness on the side for the super special coils.

If you decide to go individual ignition, you can still do the same as above, just run a 6 pin connector, so you can run the extra outputs from the ecu to the back of the connector, then still run the standard set up until you put the new coils in.

Getting everything working on the standard system is a good idea too.

Lokiel · Postby **Lokiel** » Tue Oct 27, 2020 2:12 pm

Make sure you have all the coil information you need for your ECU (eg. Dwell time).

The best GM LSx coil thread is this one started by our very own timk: https://www.miataturbo.net/diy-turbo-discussion-14/lsx-coil-thread-82744/, where you'll find an awesome custom bracket for MSM/SEs and an idiot who made his own batch-fire harness and connected the 2 plugs the wrong way around because that's what he thought he read in the OEM MSM manual (FYI: car wont run if you do that).

Seriously though, there's loads of information there including info you'll need for your coils.

The American · Postby **The American** » Wed Oct 28, 2020 7:54 pm

Thank you all, and for the posted links. I have read through both threads and will need to a few times yet.

I did see one person commenting that they had used IGN1A coils, and then I remembered that Daffy had also used these in the Problem Child. LS are definitely the more common choice.