Coil-on-Plug, tech article. Options

[akamiami]

Though the ignition system on the DSM is remarkably robust and has powered many cars into to 10's if not further, some seek to upgrade virtually every aspect of their vehicle and choose not to overlook the opportunity for improvement. The 90-99 dsm's are setup with a wasted spark ignition setup consisting of two coil packs and an external ignitor (unlike the evo8's which had two coil packs with an internal ignitor). The operation of this setup is remarkably simple and effective, firing both cylinders 1 and 4 and the same time regardless of whether they are on the compression or exhaust stroke. Likewise, cylinders 2 and 3 share the same spark event characteristics. In this way the intake and fuel mixture is ensured to be completely combusted when it leaves the combustion chamber and enters the exhaust path, preventing unwanted fuel detonation inside the exhaust manifold and turbine housing where it can potentially damage comonents such as the turbocharger.

The coil-on-plug, or COP, setup typically replaces the two coil packs with twin ignition wires running from each, with an individual coil pack for each cylinder. It is not necessary to run an external ignition amplifier when converting to this setup, though it is often done by enthusiasts in order to maximize the efficiency of the new components.

I'll run through some pictures and specifics on the setup I implemented on my GSX next.

[turbohcar]

Please do, I'm interested.

[mitsu90]

I have seen the COP setups before they are kinda pricy

[akamiami]

Mitsu, true, they are pricey (on the order of about 500) if you buy a complete setup. I'll post links for those interested in buying their setup.

DV/DT - very slick.
Buschur Racing - only 299! not bad.
Switzer - I know he has a setup, but the webpage is incomplete. you'll need to call for more information.

However, I chose to build mine and managed to do it for well under 200, I think.

parts you'll need:

4 Chrysler coil packs (2000 300M 3.5L coils)
4 toyota connectors (p/n 90980-11246) and 8 flying leads (p/n 82998-12440 for pack of 10)
1 machined plate to adapt the coils to the valve cover
some spare electrical connectors and plugs, specifically the plug that mates to the engine wiring harness from the stock coil pack if you're using the stock ignitor (power transistor)

A note on the machined plate --- I got mine from Erich Moraga off the AEM forums as he sells these as a bit of a side thing. I had to modify it a bit to be satisfied with it, but it wasn't bad. Here's a link.... Erich Moraga's Coil page.

More to come....

[SCCA Stang]

hey miami... didn;t you modify the EVO to a DSM wasted spark with an increase in power or efficiency or something to that effect????

[akamiami]

Here's a diagram for running wasted spark with two triggers and an AEM C2DI (ignition amplifier). I ran this setup successfully.


And the diagram for those running without an ignition amplifier... I ran this setup for a short time too.


The only other thing I should note was that some of the guys were worried with running 4g64 blocks that the added 6mm deck height would cause clearance issues. It was reported that this was not a concern. HOWEVER, with a cf hood and the plate I was shipped from moraga, I ran into clearance problems with my 4g63 deck height and a cf hood with the understructure ripped out, so go figure. I think the problem was that the hood I was running sat very low, I believe a stock hood would have cleared.

[akamiami]

hey miami... didn;t you modify the EVO to a DSM wasted spark with an increase in power or efficiency or something to that effect????

yes, the ignition setup on my evo has been switched over to the 90-99 dsm style with the external ignitor as the evo coils have an internal ignitor and are questionable at best. That is documented in my evo thread here. I have since cleaned it up quite a bit and if you ask me, it looks damn near stock. Thanks for reminding me that I need to post better pictures in that thread now that the ignition setup is presentable.

[natedogg]

Good info, Kris. I like the COP setup not only for the increased spark capablility, but also because it really cleans the engine bay up.

[turbohcar]

From what I gather, it's legitimately better to use an ignition amplifier than not. However, what if any benefit is there to using the setup without an ignition amplifier?

Buschur's setup seems to be the cheapest, but is that really a complete kit?

[BudmannG]

Deleted!

This post has been edited by BudmannG: Feb 21 2006, 09:36 AM

[natedogg]

From what I gather, it's legitimately better to use an ignition amplifier than not.  However, what if any benefit is there to using the setup without an ignition amplifier?

Buschur's setup seems to be the cheapest, but is that really a complete kit?

The increased spark capability comes from the fact that the spark doesn't have to travel the length of a spark plug wire. It goes directly from the coil to the plug losing none of its potency across the inherent resistence of a plug wire.

An ignition amplifier will increase spark further on top of COP, no doubt. But will you see actual gains from taking it this far? Methinks not unless you are running in the 9 sec range or quicker.

[turbohcar]

I realize the benefits of COP but, is it really worth it without an ignition amplifier?

I say you pose an interesting question Natedogg, where exactly do the members here feel that the stock ignition is inadequate?

[akamiami]

It's tough to say numbers in terms of et's or even hp figures. It may be more a case of ease of tuning than anything else. Let's say you're able to run more boost with a larger spark gap as a result of a high ignition intensity at the plug due to an amplifier or better coil. You might be able to dial in more timing, or get a little more out of pump gas than you would be able to with the stock worn ignition components.

Now, while you can either run this setup with an aftermarket amplifier or not, one consideration might be the dwell time. The AEM C2DI system is billed as having a quicker response due to it being the only true dual-capacitive system on the market. Thus, it's able to acheive full recharge faster, allowing for less propensity for ignition breakup at high boost and high rpm where dwell and response really become factors.

However, as I said before, the stock ignition setup is quite nice and adequate at a very high level. But then again, none of us seem quite satisfied with adequate...

[eclipgst]

Good to here that its working out for you. But it still makes me question why it didnt work on my car when we tryed it out. Did you ever figure out the problem or is my car just cursed with the DSM demon? Oh i also got ur message last night and was very intrigued.

[akamiami]

I think it didn't work on your car because the wires were improperly insulated in my hack job attempt to get a connector on there that would plug into your harness. When I looked closer, there was a bare copper section showing just at the connector which could have been causing severe emf/emi interference or a poor connection within the connector.

[akamiami]

[SCCA Stang]

I realize the benefits of COP but, is it really worth it without an ignition amplifier?

I say you pose an interesting question Natedogg, where exactly do the members here feel that the stock ignition is inadequate?

what about reliability....


if you increase the spark intensity with an amplifier, will you inadvertintly wear other parts faster, incuring higher mantenence costs... aka spark plug erosion, ect????

[natedogg]

While I understand where you're coming from Ben, I really don't think spark plugs and high maintenance costs belong in the same sentence. If you are paying more than 3 bucks a plug, you're getting ripped off.

[Kazz5]

... perhaps it's the cost of taking it into Mitsu to have them change the plugs ...

[natedogg]

... perhaps it's the cost of taking it into Mitsu to have them change the plugs ...

I guess I didn't consider your "wrenching" practices.