These are the exact ones I ended up with as well.

re: "raised square"... maybe that refers to the raised "115" numbering. What it means is anyone's guess.

IIRC there's no longer any real "AP1" coil packs available. Perhaps some dealerships have a few kicking around, but I think us guys with '00-'03 are SOL and must use "unadvised" coil packs if we want Denso. At least, that's what I remember concluding. It was super confusing.

 

Just out of curiosity, why is there such a confusing array of coils for the various S2000s? Is there an electrical difference between the various types?

Thanks!

 

Yeah... I got a MY03 and this entire thread is confusing AF as to which exact coil-packs will work and which to get that'll work correctly. I honestly still do not know.

 

Well honda does still list the AP1 coils.... for $200 EACH lol

And to be honest, the ones I pictured seemed to work but somehow the plastic failed catastrophically on them. I cant really see any hints of it firing into the plug tube walls or anything. Those are the exact length of the new ones, both fit perfect, no stress on them when bolting down, etc.

The car did idle rough cold (like 40 degrees or below) for the first few minutes and I had some odd running issues at WOT and when the car was very hot and being pushed hard on track, so I originally was worried those coil packs were bad thus me pulling them. However, I also just had the injectors tested and cleaned. They were flowing about 60-70% at best before cleaning. Back up to factory spec (380cc) after cleaning so right now I suspect that was most of the running problem last fall. On a cold start it would be running full rich, so between that and WOT driving I think that was all due to the injectors.

I will find out soon here. I just got a new TCT from Billman, the new coils, cleaned injectors, cleaned IACV and am doing my regular pre track season checks on the car (valves, etc) so should have it fired back up this weekend. Then maybe I can get around to the race seat/harness install, fuel tank baffle and evap system delete! It will be done one day before the first event in March!

 

This reminds me a lot of how the low impedance peak and hold fuel injectors (ex: 88-91 civic) required an external resistor box, whereas the high impedance saturated injectors (92-00 civic) did not. The ecu needed that resistance somewhere in the circuit to maintain an appropriate current. This is based on my very limited knowledge of electrical engineering (ohms law).

If we think about this logically we can probably infer a bit about what's going on here with the coils. The coils job is to convert 12v to a super high voltage to drive the spark needed for good combustion. If the non resistor type coils are used in the 06-09, then ohms law says we've got the same voltage (12v) and less resistance (no resistor in the coil) so therefore current must go up. With increased current comes more heat and it burns something up (it would have to be either the coil, the ecu, or the wiring in between) seems like the fsm is suggesting the coil is what dies.

I could be completely wrong about this, but it seems to make sense to me.

 

I'd definitely be interested in how the new coil packs work out. Thanks!

 

How are yours doing so far?

 

One of the cases where you wish Honda would be clearer in the FSM. "Dont use this parts BECAUSE... The difference IS....".

So far, the conclusion is that some pre -06 model runs the late Coils with the square. People buy the coils online, dont know about the difference with the raised square and nobody pays attention, install them, and go. So far without any Problems.
But the Factory service manual clearly states tha you should only use the ones with the square in the later modells.

If i dont read this thread, i would also be unaware of the warning and the difference between the coils, because in both of my FSM this warning is not included.

 

So, after reading this thread, i am 90% sure that one can run the later raised square coils in pre -06 F20C engines without electrical problems.

I was just flipping through british and german car part stores, it´s a mess. A giant mess. Nobody makes a difference between years and raised square / non square ignition coils. The later Models with the raised square are out there to buy, but i only found one (trustworthy) aftermarket company here in germany so far wich offers them. Taking in account that the S2000 is a 20+ Years old rarity here, wich maybe contributes to the fact that nobody cares about the accuracy of the catalouges.
I even found a reputable shop here in Europe wich is specialized in Honda parts wich offers the OEM Honda ignition coil 30520-PCX-007 as "Fits all Modells 00-09". Go figure.
The average customer has no chance to avoid this trap.

I wonder how many S2000 users worldwide simply buy aftermarket Ignition coils, dont know about the difference wich the raised square makes, just install them and drive on. Are there any known cases where the ECU or something else was damaged by mixing up Square / non Square Ignition Coils?

I would say that i learned something regarding the technical details and differences of the S2000, but even with my US and German original FSM, i would never know about the difference between the Ignition coils if i dont have read this thread.

 

It is definitely in my service manual. Keep in mind if your service manual came out before 2005 it would not because the 2006 was not out yet.

But as I saw, only one of the 2 ribs shown exist on the coils I got. Also zero mention specifically of a raised square. Im wondering if that one rib is the raised square being talked about? It is under the word japan and from the side looks like a raised square.

im wondering if what ever marking conventions they mentioned are not marking conventions and simply a convenient way to tell them apart other than the part number. And years later when parts were superseded they simply did not keep the same marking. Aka the raised square, ribs, etc were not some purposeful way of marking the version but rather were just easy features to use to identify at the time the manual was published. So there was no expectation that new part numbers after the car was out of production would follow those inferred marking conventions