Driving COP's with DTA S40

[mefmotorsport]

I have a customer who wants to use an S40 on a 4 cylinder BMW M42 engine but he wants to retain the COP's

Has anyone ever tried driving 4 COP's on a 4 cyl engine in wasted spark mode with an S40?

Apparently if you try and drive 2 coils directly from an output the internal driver chips would overheat and destroy themselves. Conversely if you wired the COP's in series then you get a very poor spark as you only put 6v through each coil primary (and of course much reduced primary current ie half the voltage = 1/4 the power).

So, I had an idea about using an external coil driver such as an EDIS unit, hopefully this would have the capacity to drive 2 pairs of COP's wired in parallel from the 2 S40 drive signals. Obviously you would select "use external amps" in the general engine settings. Maybe an 8 cyl EDIS unit would be better having 4 outputs, one for each COP?

But, this edis unit, is it just a coil amp or does it do more? I seem to think that some of these are ignition only ecu's and take in the crank sensor signal, maybe I would need a different sort like say a Subaru one that is definitely just a coil driver amp. or maybe one of these: http://www.ebay.co.uk/itm/Ignition-Ampl ... 4170c99d4a

Any thoughts or comments?

Martin

[mefmotorsport]

I since found out that the EDIS module is more than just an amplifier, it has electronics in it that use crank signals and feedback to the main ecu so obviously no good for what I need, the Cosworth ignition amp or the Subaru one I mentioned above look like a better bet.

Martin

[stevieturbo]

Clarify please.

Is it just a COP you want, or an inductive COP ? Or is there some specific coil you want to use ?

EDIS is a no go.

As long as you use an external ignitor, whether built into the coils or external I see no issue running multiple coils off each driver. There shouldnt be any load on the ecu driver to cause it damage?

I assume the S40 is the same as the other models in the range in how it drives a coil ?

The only issue I came across when doing some testing is that the DTA will trigger these off/on triggers with 12v.
My LS coils would typically be charged/triggered via 5v. OEM coils dont seem to have an issue with the 12v though. Other models might not be so happy and might need 5v to be reliable.
I guess a change in pullup resistor could drop that trigger voltage down though ?

If the coils are normal 2 wire inductive, I dont see any way of firing these directly via the DTA in the manner you want.
In series is an option, but not ideal as you've already said unless you had the likes of an MSD or other voltage booster in place.

But running a 4 channel external amp and pairing the amp inputs should work just fine.

[mefmotorsport]

The coils would be the standard BMW inductive types of the M42 engine so yes 2 wire (think the 3rd wire is just a ground) so should be no problem from something like this http://www.efi-parts.co.uk/index.php?pr ... es#inquiry a bit pricey though? same here and data sheet: http://www.aemelectronics.com/4-channel ... river-1201

Martin

[mefmotorsport]

I found that many Audi/VW/Seat/Skodas have what looks like a channel ignition amp, Bosch 4D0 905 351 or Hitachi 8D0 905 351. I found I can buy one of these new for £65

That might well be the solution for my customer

I might even get hold of one and have a play as it might well be an option for anyone wanting to run COP's on an S40.



martin

[mefmotorsport]

Thinking about it, if this works out it would be a useful option as there are plenty of engines that have COP's fitted as standard which would be nice to retain, ie the Ford Duratec for one, at present you have to either fit a wasted spark coil or use an S60.

Martin

[stevieturbo]

I think all you need is a "dumb" amplifier. ie one that doesnt muck about with dwell or anything, it just provides the triggering for the coil.
early Subaru would be like that. There are loads of Bosch ones

Motec give some info on different ones.

http://www.motec.com/downloads/downloadsappdrawings/

http://www.motec.com/filedownload.php/m ... docid=1267

Googling the part number Motec used... Megasquirt then follows

Bosch 0 227 100 211

http://www.microsquirt.info/Bosch_211.htm

[mefmotorsport]

Thanks Stevie,

That's exactly the unit i referenced back to earlier, the same module for the Audi 1.8T, looks like it will do the trick.

Cheers,

martin

[katana]

Or use one of these - just pair up 1 & 4 and 2 & 3. Prcey, but work reliably.
http://msextra.com/doc/ms3/pix/bosch-211.gif

Whoops repeated above info !

[mefmotorsport]

Thanks, yes I have bought a used one to have a play with!

Martin