Wasted spark?!? School me

[TStroop]

Does anyone have a good write up on a wasted spark or a coil over plug setup for an m20 i have a 87 32e with a 88 325I engine and am really curious about this. thanks in advance

[nando]

Well first of all you need standalone engine management capable of such. a writeup isnt really possible since the options are endless.

[TStroop]

ok i gotcha

[Holland]

Every time I read this thread title, I am reminded of the wasted spark whatt18yahoo dude.

[billybobjoseph]

I'm not a big fan of wasted spark systems. Seems to me it applies more wear to spark plugs and cables than necessary, although those parts will still last a long time. A coil over system would rock. These systems are operated by a much more advanced brain and no distributor.

[nando]

Wasted spark works fine. Its still far more reliable than the cap and rotor. You cant tell any difference between wasted spark and COP on a running motor - I can switch between them on the fly.

[billybobjoseph]

I'm not saying that wasted spark system is not good, just saying I'd go with coil over if I had the option. Each plug in a wasted spark system is firing twice the number of times it would in any other system, so half the life of the plug and cables.

[nando]

Ive never seen a cable wear because of the electricity flowing through it - usually they are just done because they are 20yrs old and the sheathing is hard and brittle. There is some wear on the second plug, but its because of the direction of flow. Merely sparking a plug will not wear it, its the combustion that wears them down. Firing them twice doesnt make any real difference.

The primary benefit of cop is being able to adjust timing per cylinder. If I were to guess how many here have done that, it would be near zero.

[billybobjoseph]

So you're saying no combustion means no wear? Ok. I don't see how you could hook up either system without a radically different brain. You wouldn't want to use coil over and still time it with the distributor, be a waste of effort. Plus you'd have to figure out a way to get the signal voltage right at each coil after having sent it across the gap at the rotor and distributor and down the cable.

[nando]

I have a standalone ECU. Switching from wasted spark to COP is as simple as a menu item change. I didnt say anything about using either with any of the stock stuff.

[billybobjoseph]

:D the truth comes out. What kind of ecu and where did you get it?

[matt0300]

Megasquirt! Diyautotune.com if u hate wiring they do have a plug and play verision where u just have to run a new vacuum line.

[nando]

:d the truth comes out. What kind of ecu and where did you get it?

ms3 :)

[TStroop]

Well someone should GIVE me a megasquirt plug and play setup then. I understood the concept i was just wondering what was involved in doing it..