M4 Pro coil recommendations

Discussion and support for MoTeC's earlier generation ECUs

M4 Pro coil recommendations

Postby Dezi-D on Fri Jul 09, 2021 11:32 pm

Hi all,

When I comes to ECU and ignition coil combinations I am sooo out of my league. I have no idea what to get, but I hope the knowledge pool on this forum will pull me through this fog of smart-switching and dumb coils. So any help would be greatly appreciated.
The basic configuration is this:
Engine is a 4ZC1T 2litre with a GT28RS turbo, 440cc injectors with 2-3ohm impedance, 2.6 inlet manifold and runners, 3” exhaust, etc.
The EMS is an M4 Pro, serial# 4612 - EPS 0207 (3D upgrade, ignition upgrade, sequential upgrade, wide band lamda metering, traction control, etc). It controls a Rodeo electronic distributor with custom 60-2 optical trigger wheel to suit MoTec ECU.

I’m currently running an unknown single ignition coil (possibly a Ford AU?) because the previous the Procomp CDI Ignition PC 6A with high energy coil recently packed it in. Given the engine still needs to be dynotuned due to its base mapping, the car is just sluggish and way down on power now, and I’m leaning towards the unknown coil being the culprit.

Guys I need help selecting a decent single coil replacement and a 4 coil replacement (for later on). Where I’m lost on is whether my MoTec has the capability and switching circuitry so I can run a ‘dumb’ coil, or do I need a smart coil to do the switching? And is there more to it than that?
Any help to clear this up would be great. Thanks in advance guys. :)
Dezi-D
 
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Re: M4 Pro coil recommendations

Postby SDean on Mon Jul 12, 2021 10:06 am

Hi,

It is possible that the dwell curve for the unknown coil that you have is wrong, and the coil is either not being dwelled for long enough to get a full charge and thus has a weak spark, or is being over dwelled, and is either being cooked from excessive current or is self discharging to protect itself. I would lean towards the under dwelled condition.

The M4 doesn't have internal IGBT drivers so it needs to have either an external igniter or smart coils used, connecting a dumb coil can get the coil to fire, but will rapidly damage the ignition drivers in the ECU.

As for coils to be used, if you can run the four individual coils compared to a single coil through a distributor, you will have better control of the spark timing and also have the option of a wider selection of coils.
Stephen Dean
MoTeC Research Centre Melbourne, Australia
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Re: M4 Pro coil recommendations

Postby Dezi-D on Mon Jul 12, 2021 10:34 am

Hey Stephen,

Thanks so much for your valuable input. Is a MoTec external igniter a preferable option than an integral smart coil setup? If I went smart coil what are some specific features that MoTec recommends for the M4 pro?

Beyond that, if I was to skip the single coil setup and install the 4 coils straight away, will a tuner need to make adjustments to the ECU at the same time? I have a strong sense the answer will be yes.
Dezi-D
 
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Re: M4 Pro coil recommendations

Postby SDean on Thu Jul 15, 2021 1:39 pm

My personal preference is to use smart coils as it means that there is one less possible failure point in the system. The M4 is pretty open when it comes to the coils used, most coils on the market can be used with them, I would look at a commonly available coil if I was adding coils to an engine (unless there is a specific coil on plug that works with that engine) so that if one does need replacement, they are easy to source.

You may not need to have the engine retuned to suit the new coils, but I would have a quick check done to ensure that the timing remains correct. If this is the case, then the current tune should be able to be used. You may find that with the new coils you can get a bit more timing into the engine compared to a single coil running through a distributor.
Stephen Dean
MoTeC Research Centre Melbourne, Australia
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Re: M4 Pro coil recommendations

Postby Dezi-D on Thu Jul 15, 2021 1:57 pm

Thank you again Stephen, a true asset to this forum. Cheers
Dezi-D
 
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