3.4 single plug = upgrade coil?
 

Folks

I've been running a 3.4 conversion for several years now, but have always had a slight doubt whether the standard motronic coil was up to the job.

I'm running a single plug setup with remapped motronic and 98mm Mahle p and c's, and wondering whether I'd benefit from a coil 'upgrade' eg nology pfc-m70

I have just bought a standard replacement Bosch coil but would sell this on if the nology (or other) is deemed worthwhile.

Thoughts please?

The diameter of the cylinder has nothing to do with what is needed to get the spark plug to fire.
(Well, in theory if it increased cylinder pressure when the spark is jumping the higher pressure could inhibit the spark event but that kind of pressure would ensure that the car would detonate too.)

The whole spark thing is the biggest place where physics leaves people's brains and voodoo comes in for a dance.

- A basic truth -> "You can't get more burnt then burnt."

If you started the fire in the combustion chamber at the correct point in the Otto cycle then the ignition system had done its whole job.
The only meaningful changes you can make are:
- When the spark fires
- Where the spark fires (different length of plug nose or moving the plug location)
- Temperature range of the plug (too cold so if fouls, just right so it works, to hot so pre-ignition starts)
- Multiple ignition points (twin plug. NOT multi gap plugs)
- Changes to components to increase their reliability


It sounds like you are lighting the fire. My question would be "Is the advance curve correct for the engine?" or "How can I give this thing the twin plugging it really wants?"

Your stock coil is MORE than enough for the job and I'd recommend not wasting money on junk like Nology.

Thanks both, looks like I'll stick with standard! Q - do coils wear over time, or are they considered 'digital', i.e. they work or they don't?

What about a "Direct fire unit" or direct ignition system like the one from Electromotive that claim to provide a stronger and longer spark duration. Would this help the combustion with better timing, and help to avoid misfires ?

Your thoughts please,

Stock coil on mine works fine.