Coil on plug conversion

[Mark]

Excuse my ignorance but I am converting my BMW E30 M3 to wasted spark standalone ignition set-up using DTA and I was wondering if this meant I could run coil on plug?

Any help using small words and easy to follow phrases would be much appreciated.

Thanks, Mark.

[vitesseefi]

It depends.....

To run wasted spark on a 4 cylinder the ECU only needs two ignition drivers (outputs) as each wasted spark coil fires two plugs at the same time (one spark being wasted as that cylinder is on the exhaust stroke).

To run coil on plug (COP) your ECU needs 4 ignition outputs as each cylinder has a separate coil.

So if the ECU has 4 ignition outputs you can probably use COP. It is a question for DTA really - or which ECU are you using?

Nick

[Mark]

DTA S40 Pro.

[vitesseefi]

It's only got two coil drivers, so you can't do COP on a 4 cylinder.

Nick

[cobblers]

Can't see any reason why you can't run COP as wasted spark though. If you get coils with intregrated ignitors then the load on the trigger pins on the ECU is minimal, so you shouldn't have any issues pairing them.

However it does boil down to why you're wanting to convert to COP - for better coils, or for individual control?

[welshpug]

with an S40 its only wasted spark, I'm not too familiar with the S14 engine, a brief browse on the internet they look like they would be compatible with a wasted spark unit like an 8v XU or earlier 8v TU peugeot/citroen engines.

those leads are staggeringly expensive aren't they?!


I'm running the same ecu on a 2.2 16v XU that Sandy will be mapping in a few weeks, that has the coil I mentioned and will be using GM 16v plug leads, I'm not sure if they will be long enough for the S14 engine, the plugs look like they're quite a long way down.

[ChasR]

Don't COPs work on a wasted spark principle? I am fairly sure that the Renault F4Rs with the COP arrangement (like the Laguna) did when I last worked on it ; I needed an ignition source for an LPG ECU .

[welshpug]

not these days, most are fully sequential operation, hence using the camshaft position sensor.

not familiar with the later f4r, but i think they used individual pencil type coils so its likely to be sequential if driven directly from the ecu, if its a cassette unit with just a 4/3 wire plug then its wasted spark.

[ChasR]

If this manual is true and relevant (it seems it on the face of it) then COP can be done:

www.dtafast.co.uk/download_files/Manuals/S%20Series%20Manual.pdf

[820]

I'm using the DTA S60 and converted the Rover to coil on plug (BMW M3 Bremi coils), was a few years ago i wired it up but if the S40 uses the same system then yes it can be done

[Clamity]

I've got some VAG pencil coils with ignitors that I figured probably won't work well in a wasted spark setup. I found they need quite a bit of dwell time to charge properly, so firing once per revolution would mean a weaker spark or missing sparks at maximum revs.

[welshpug]

Mar 6, 2017 1:26:27 GMT 820 said:

I'm using the DTA S60 and converted the Rover to coil on plug (BMW M3 Bremi coils), was a few years ago i wired it up but if the S40 uses the same system then yes it can be done

no, there's 4 ignition outputs on s60, only 2 on s40.

[vitesseefi]

The manual seems to cover the whole of the S range not just the S40.

I suppose you could connect COPs in parallel pairs but I'm not sure how well that would go electrically. I also don't really see what you would gain from that over a wasted spark coil pack.

Plenty of choice of those around and some even have the ignitors built in
www.ebay.co.uk/itm/AUDI-SEAT-SKODA-VW-IGNITION-COIL-PACK-032905106B-032905106E-032905106-NEW-/150976510493

- great idea if I could only find a 6 cylinder one

Nick

[ChasR]

Mar 6, 2017 20:37:08 GMT vitesseefi said:

The manual seems to cover the whole of the S range not just the S40.

I suppose you could connect COPs in parallel pairs but I'm not sure how well that would go electrically. I also don't really see what you would gain from that over a wasted spark coil pack.

Plenty of choice of those around and some even have the ignitors built in
www.ebay.co.uk/itm/AUDI-SEAT-SKODA-VW-IGNITION-COIL-PACK-032905106B-032905106E-032905106-NEW-/150976510493

- great idea if I could only find a 6 cylinder one

Nick

In Mark 's case it would be taking out a very pricey set of leads out of the equation for something more potentially reliable and easier/cheaper to live with in the long term. Arguably a generic coil pack would also get around it too but I guess the COP would be a tidier way to do it and one less thing to take the guesswork out of.

Are you based near Brand's Hatch Mark? I did bin one of my old pencil plugs from my E46 (it was dead) but I do have a spare in the boot you are welcome to try. I'll have to see if they are batch fired or sequential on my car.

[Splitty456]

Mar 5, 2017 11:48:12 GMT Mark said:

Excuse my ignorance but I am converting my BMW E30 M3 to wasted spark standalone ignition set-up using DTA and I was wondering if this meant I could run coil on plug?

Any help using small words and easy to follow phrases would be much appreciated.

Thanks, Mark.

In short, yes.

But as mentioned, you need to use coils with built in ignitors - all the BMW ones i've seen are of this type. Basically any coils with 3 or 4 pin plugs will work.

And to those saying you'll get weaker spark, i'm running coils from a 1.3 yaris in wasted spark on my starion - they seem fine at 10psi boost and 7500rpm!

[welshpug]

you could ask sandy if he knows what parts are usually used, he's mapped a few now, or Kieran at KSP as he's built a few, probably mapped by sandy anyway, or mark shillaber maybe.

[mk2cossie]

Digging up this old thread to see if there's any new light or experience on the subject?

Thinking of fitting A/C to my car, and the current coil pack is in the way. Going to COP would free up a big space at the bulkhead for me

[ChasR]

You're on Emerald, aren't you bud?

I think a number of ECUs now have 4 ignition drivers in the aftermarket.

[mk2cossie]

Jan 28, 2024 10:17:18 GMT ChasR said:

You're on Emerald, aren't you bud?

I think a number of ECUs now have 4 ignition drivers in the aftermarket.

Yes indeed! Although K3, not K6.
Was thinking of getting COP and making up a loom to run off of the current coil pack.
And run the COP as 3 sets of 2 as wasted spark