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is COP worth it? 
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QFP80 - Contributor
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Been reading up on the advantages of COP over a single coil, from what I have been reading the advantage does not seem very strong. Then again I worry about the information that I have been reading, some people have more opinions then experience.

So to the people with experience, is it worth doing? (cost vs benefit)

If so how do I pick one for a 289 small block windsor?

There is a very common after market ford unit for around $80 http://amzn.com/B0031ZDU62
or second hand GM LS1 gen 3 coil pack for about $200 ($400 new)


Wed Oct 19, 2011 2:10 pm
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Distributors suck, they're marginal on medium revving four cylinders and low revving six cylinders and are responsible for the popularity of CDI in V8 circles :-)

viewtopic.php?f=24&t=48

It's not well written, look at the date I posted it, but I might give it a clean up later today. The basic points are relevant, though.

Other than dwell time, the main advantage is getting rid of the air gap and oxidation points at the rotor and cap.

The secondary advantage CAN be to ditch leads too, BUT, when you do that you typically introduce a carbon rod into the path to add resistance and cause the coil to discharge more slowly with a longer spark. Leads fill that roll for you.

http://i50.photobucket.com/albums/f323/ ... 0_4471.jpg

That's my CNP (Coil Near Plug) setup on my truck in NZ. I had a very very very poor ignitor setup on it at the time, IE, the megasquirt output circuitry was wrong/bad, and it wouldn't even light up a timing light, BUT, it WOULD light the mixture off at 7500 RPM and 18psi making around 400 crank horsepower from two litres. With a proper ignitor drive you're good to very high cylinder pressures.

Wasted spark with good coils is typically good to around 9k RPM or so, but can't really be used with anything that leaves combustible gas in the inlet manifold, depending on cam profile, as it could cause an explosion.

Pseudo COP/CNP with wasted spark drive and double sparks has the same issues and rev limit.

Wasted can give you funny results if one plug is fouled too. On a conventional setup in good tune, wasted is a great solution out to very high power levels.

Now, back to FreeEMS talk, in the short term, you're limited to dizzy anyway due to the output count limitations, unless you run the injectors in batch, then you could do wasted spark. If you're happy to wait an indefinite time until Sean's code is ready to use then you'll be best to go COP/CNP and sequential, assuming your CAS input supports it, which it does, if you're using the 4g63 style one.

Clear as mud?

In terms of choosing hardware, choose whatever fits best.

Wasted spark coils from subaru flat fours are decent - I know a guy making 500hp on a twin turbo 1uzfe lexus v8 with those.
LS1 second hand coils at 200 oz dollars sounds pretty damn good, though, I'd jump on that :-) Those are hot, reliable, easy to use (logic input) and readily available, in short, a good choice :-)

Fred.

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Wed Oct 19, 2011 2:34 pm
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Re cost, that should be a non issue, the parts should be all second hand and relatively cheap.

I'm a big fan, but all of the above applies if you're purely looking for a practical option.

Fred.

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Wed Oct 19, 2011 2:35 pm
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QFP80 - Contributor
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Thats some great info, thanks! COP it is then :lol:

My engine does not get any where near 9k rpm and the cam profile is stock so there should not be any issues with wasted spark.

Will grab that LS1 gen 3 coil pack. Wow the plugs cost about $80 ontop of the coils, was not expecting that.


Wed Oct 19, 2011 2:58 pm
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Count yourself lucky! The plugs that I use are 20 - 30 dollars a piece :-) LS1 is a good choice, simis is using them to great success.

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Wed Oct 19, 2011 3:40 pm
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LQFP144 - On Top Of The Game
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Good choice.

Another advantage of one coil per spark plug is that you can do crazy retarded ignition events for anti-lag. ;)

COP is just a simpler setup, and IMO better in almost every way. The cost is usually comparable.

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Wed Oct 19, 2011 9:54 pm
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An interesting point, thanks for sharing


Thu Oct 20, 2011 10:45 am
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the antilag point it mute really.
I pull 64deg before tdc with the Group A rally car in some points. and it is crazy!!
12-15psi off the gas :D

What cop is good for is individual cylinder control.
Along with the fact you have a longer charging time on high revving or many cylinder engines.


Thu Oct 20, 2011 12:48 pm
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LQFP112 - Up with the play
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The LS1 coils are very easy to use and work well.

I'm using them with the standard copper core plugs recommended
for my engine with no problems. $2 each.

In North America, at least, the coils are abundant used.

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Thu Oct 20, 2011 5:59 pm
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viewtopic.php?f=24&t=48

I just tidied up that thread and linked this one from it, and, in the process, noticed that it was the 48th thread on the forum. This one is 1376 :-) We've come along way!

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The ever growing list of FreeEMS success stories!


Thu Oct 20, 2011 8:12 pm
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