[cribbj]

I’ve recently converted my 550 ignition from the twin coilpacks and bundled secondary leads to a COP (Coil on Plug) system. This thread is about the conversion, and for those who aren’t familiar with COP’s, and their benefits, we can start another thread to discuss those.

This conversion could probably be done on 456’s, 355’s, 348’s, TR’s, etc. – any of the engines with a crank triggered ignition could probably be done very easily.

Best of all, the conversion is easily reversible, as no harness mods are made, and no holes are cut or drilled. I’m considering making a “kit” for this, and with a kit, a fairly handy owner could easily do this conversion in a day, or maximum, over a weekend. Obviously, if the kit and car were delivered to a knowledgeable shop, such as ECS of Virginia (shameless plug for one of my favorite shops and technicians), it could be done in a day. BTW, Josh was my sounding board throughout this whole exercise from Christmas until earlier this month, so he's very familiar with the project.



The 550's stock ignition is very similar to the Ford EDIS4/6/8 which I’ve worked with previously, and am fairly familiar with. A six tower dumb coilpack receives three ignitor based signals from the ECU and generates sparks for six cylinders, so it is a waste spark setup. On the 550, there is a six tower coilpack for each side of the engine.

The side of the coilpack is marked like this:



With the help of a 9v battery, I was able to determine which of the primary terminals in the pic below, corresponds to which of the towers in the previous pic:



And here is the schematic:



With the firing order of: 01-12-05-08-03-10-06-07-02-11-04-09

And grouping the complementary cylinders above each other:

01-12-05-08-03-10
06-07-02-11-04-09

Then splitting it according to bank:

Right--------------------Left
01-05-03---------------12-08-10
06-02-04---------------07-11-09

We now know the right side ECU harness is firing the primary terminals of its coilpack in this sequence: 3-2-1, while the left side ECU harness is firing its coilpack in this sequence: 2-1-3. This is an important point to remember, in order to avoid misfires later (ask me how I know)

These coilpacks produce a very nice primary ignition waveform, with a charge (dwell) time of some 3.2msec and a spark duration of 1.8-1.9 msec:



Next, it was time to do some fitment testing in the Maranello heads. The first coil to try, of course, was the 575 Maranello’s coil, but it just didn’t fit. The 575 valve covers are different enough from the 550’s that it was like trying to force a square coil into a round hole (literally). A pity, because it would have been good to have a 100% Ferrari solution, however the mods necessary to the 550’s valve covers, not only to fit the coil into the plug well, but to hold it down afterward, would have been prohibitive:



So on to some others. Here’s a Toyota coil on the left and a Chrysler 300M coil on the right. Both are popular choices in the COP retrofit market.



These are the 300M coils which fit well into the plug wells, but are standing too tall:



They also fouled the throttle linkage. Good coils, but we can’t have this:



Even tried some Accel coils, but they were way too big too:



Here are some very low profile Chrysler SRT coils. They fit well, and once turned a bit, they didn’t foul the throttle linkage. These coils worked fine and I ran the engine with them:



But then things got ugly when it was time to hold them down. Ugh, we can’t have this in a Ferrari engine bay:



So then it was time to try the type of pencil coils used on high performance motorbikes and Formula 1 motors. Here’s one on the right with the Chrysler 300m coil on the left:



They're MUCH shorter than the 300M:



I think we have a winner:



Next I calculated the performance of all these coils - this spreadsheet shows that the pencil coils are very sensitive to charging voltage, but have the capability to put out more than sufficient energy. (Not quite as much as the stock coilpack, but then each coilpack winding is firing 2 cylinders, where each pencil coil will only be firing 1 cylinder).



Then I ran some actual energy measurements by firing the coils into a dummy load bank array of Zener diodes with a breakdown voltage of 760 volts, and calculated the spark energy based on the measured current through the load and duration of the "burn". This test was done on each coil singly, then with two coils wired in series, then in parallel. Then finally, all measurements were repeated using an HKS Twinpower DLI ignition booster. The HKS box is a highly regarded solution for assisting stock ignitions on cars which have been turbocharged, and I felt it could be useful in this situation. As can be seen, the pencil coils really responded to it, and produced even more spark energy than the OEM coilpack system.



Based on the above, I wired the coils in series, and used the HKS box, and here is the final schematic:



Next, off with the old system:



And on with the new:



And how does it run? Very well, thank you! The idle is very good, response is excellent, and the car pulls strongly to redline without a hint of a misfire. There are no CEL’s, and the car passed the TX emissions inspection with no measureable change from the stock ignition. (N.B.: Prior to emissions testing, I put a set of Bradan straight pipes on the exhaust to keep the right & left banks completely separated from each other, and had the COP system on the right bank, and the OEM coilpack on the left) The HKS box did not seem to make a measureable difference in the ignition, however I’m keeping it in the system for insurance.

The only issues encountered so far are:

• The pencil coils use internal gripper teeth to grip the top terminal of the spark plug (after the spark plug nut is unscrewed). This top terminal of the plug is fairly soft metal, and after several install/remove operations, the gripper teeth tend to smooth down the plug terminals and no longer grip them tightly. Since this is the sole means to “hold down” these coils, it was easily rectified by adding a short extension to the top of the plug, made of harder metal. This necessitated adding a longer boot onto the coil, and there is now a requirement for a deeper well spark plug socket to remove the plugs. Not a problem as long as your mechanic has one.
  
  
• The initial type of sleeving used for the harness did not withstand being near the exhaust manifolds and melted. This sleeving was rated for 260 degrees F, but fortunately, the conductors within were rated for 392 degrees F, and they were fine. I'm now experimenting with some 1200 degree fiberglass sleeving and it seems to be fine.
  
  
  
  
  
• Several types of heat shrink tubing have been tried, and most shrink too much, then embrittle and split due to the extremely high temps near the exhaust manifolds. I'm now trying a different type of heat shrink and preliminary results look good:
  
  
  
  

The next round of testing will be putting the system on either a Leonardo or ST-5 diagnostic scanner to see if either one of these tools picks up any errors.

Stay tuned!

[cribbj]

My ace harness builder just finished the new COP harnesses so I wanted to show them off here. I see the thread has had over 120 views, but no comments. Odd.......I don't know if people aren't interested in this sort of mod thread, or perhaps are just shy.

The top two harnesses are obviously the ones that connect the coils to the car harness, and the bottom 4 harnesses are the ones that are necessary to connect the HKS Twinpower DLI booster into the system.

I tried to make the system modular so if the HKS box ever causes problems, or I want to eliminate it, it's very easy.

I can't wait to get home & get these installed!

[agp22]

Can you advise what is the advantage of this mod?

We have a Cayenne that has these COP things, and 2 of them have already gone wrong and had to be replaced at around 200 a piece.

[cribbj]

Ouch, yes unfortunately the Cayenne (and especially the Turbo model) COP's have had a very bad reputation, but they shouldn't cost $200 a pop. If you like, I can PM you a much cheaper source for these.

Back to your question, the biggest advantages of COP's are:

1. Elimination of the lossy and noisy (EMI) secondary leads.

2. Stronger spark when in a sequentially fired system & more suitable for higher RPM's (which is why they've been used on F1 and motorcycle engines for years)

3. Easier & much less expensive to replace than the bundled secondaries (at least on 550's and 456's)

4. Aesthetics - a much cleaner looking engine bay without all the spaghetti wiring of the secondary leads.

COP's are really just the next step in the evolution of ignitions. They're not the quantum leap that was gained when mechanical points in the distributors were replaced by transistors, but are more like when the distributors were eliminated and crank triggered systems took over.

Disadvantages of the COP's:

1. As you've found, some models can be unreliable. Unfortunately, the Cayenne's coils (which are made by Beru) probably have had the worst reputation of the lot. The Germans are really lagging behind the Japanese who have this technology sorted.

2. In the early days of COP's it was a bit more difficult to diagnose a cylinder misfire, but tools and procedures are now more available, and with advancing technology, misfires are not that common anymore.

3. COP's are transformers, and the natural enemy of all transformers is heat. Locating a COP down in the hellhole of a plug well, instead of on top of the engine isn't doing it any favors, and will undoubtedly shorten its lifespan. Having said that, I've put 70K miles on a '94 vintage high performance turbocharged Japanese car with one of the earliest sets of COP's and never had a problem with them.

[gothspeed]

Great thread!!

[cribbj]

Originally Posted by gothspeed

Great thread!!

Thanks; the next installment will be coming up shortly.

I've figured out how to hook up a state inspection exhaust gas sampler to the 550 engine before the cats, so I'm going to set up a test with one bank running on the stock ignition and the other bank on the COP's and see which runs cleaner/better. The results I obtained previously, after the cats, showed no difference, but that could have been because the cats were doing their job.

Too bad you're not a little closer to Houston, I'd sure like to test this system on a 355.....

[Boxer]

Did you decide to make the conversion kits up?

[cribbj]

Originally Posted by Boxer

Did you decide to make the conversion kits up?

Boxer, not just yet - I want to do some additional testing with a new COP probe I just picked up which should give me a better idea of the kV & energy levels in situ with the engine running on a rolling road.

I also want to test with the exhaust gas analyser to ensure it's running as clean or cleaner with the COP's as it does with the stock ignition.

[tazandjan]

John- I would not actually expect the COP system to show up in emissions improvements or hp increases initially, but rather to be more reliable and with more consistent results as the miles pile up and their is no degradation in primary leads and coil pack performance. The same was true with the change from points carrying primary current to capacitor discharge units, where the points only carried switching current, to today's distributorless ignition. There was no difference in initial performance, but over time the newer systems were more reliable and showed less degradation in performance between the now non-existent tune-ups.

[cribbj]

Taz, I would expect the same as you, but some ignitions (crank triggered and COP types) have been known to "find" a bit of HP on dynos, while others (single coil, distributor, etc.) lose it. This is due of course to the accuracy of crank triggered ignitions and the long dwells and full charging that COP's and coilpacks permit.

Then there are others that run really well on top, but produce a rough idle down low due to their extremely fast spark (CDI).

This ignition, with the addition of the HKS DLI module, is a hybrid between inductive and CDI, so it has an acceptably long spark, and plenty of energy on top, and I just want to ensure it's running as clean as the OEM setup.

[gpw]

Great job, in my opinion. Was thinking about doing the same thing, but always busy with other people's cars. Would like to patisipate in this project. Let me know. And what is the exact aplication of coils of your last choice?

[gothspeed]

Originally Posted by cribbj

Thanks; the next installment will be coming up shortly.

I've figured out how to hook up a state inspection exhaust gas sampler to the 550 engine before the cats, so I'm going to set up a test with one bank running on the stock ignition and the other bank on the COP's and see which runs cleaner/better. The results I obtained previously, after the cats, showed no difference, but that could have been because the cats were doing their job.

Too bad you're not a little closer to Houston, I'd sure like to test this system on a 355.....

Cool!!! I will keep an eye out for any more posts !!! I really like the COP idea, as it is my understanding this mod is more condusive to a steady ignition idle and more consistent burn! As many know, any misfires send unburnt fuel into the exhaust, leaving the manifolds and cats to deal with it . This of course leads to higher exhaust and cat heat, which really hastens their demise .

I have a question; does the wasted spark arrangement of our fcar ignition, create any dwell issues with the COP? That would be my only concern thus far, as you know that may affect spark efficiency at upper RPMs. Other than that I think it is a brilliant idea!!!

PS that custom harness looks gorgeous!!

[bretm]

Originally Posted by gothspeed

...PS that custom harness looks gorgeous!!

Agreed, they look darn good.

John, any update on how the heat shrink is holding up?

[cribbj]

Originally Posted by gothspeed

I have a question; does the wasted spark arrangement of our fcar ignition, create any dwell issues with the COP? That would be my only concern thus far, as you know that may affect spark efficiency at upper RPMs. Other than that I think it is a brilliant idea!!!

PS that custom harness looks gorgeous!!

Thanks Goth, from all external indications, the dwell is monitored/controlled by the Motronic, and these Hayabusa COP's, even though they're wired in series, still have a lower impedance than the OEM coilpack, so they have a shorter dwell. It's another reason I decided to use the HKS box, just for extra insurance. I've had no indication of misfire at upper RPM's, but I have to say the COP's seem to produce a bit more of a lopey idle than the coilpack. The Motronics have not thrown any error codes, and the plugs are cleaner on the COP side than on the coilpack side, so I'm not sure what's with the idle, unless the different RLC response of the COP circuit from the coilpack is causing the timing to change slightly.

Primary scope traces are normal, but I'm sourcing some additional instrumentation where I'll hopefully be able to monitor the traces on the secondary side, which is where I really want some better data.

Originally Posted by bretm

Agreed, they look darn good.

John, any update on how the heat shrink is holding up?

Bret, the heat shrink on this harness is doing fine - no hardening or brittling issues, and all the latches on the connectors still work fine. Unfortunately my harness guy doesn't share his sources (like many who make a living from their IP) so I'm unable to tell you what brand it is. Since I'm only a hobbyist, I can tell you that I went through 5-6 brands of heat shrink before I settled on the expensive 4:1 polyolefin McMaster stuff, for my own limited harness work, and it's holding up well too.

[cribbj]

Goth, in rereading your post and question, I may not have given an adequate response. I think your question really related to the (lack of) dwell time at high rpm due to the wasted spark ignitions on these engines, and whether this would adversely affect these coils?

Because of their OEM application (the Hayabusa has an 11,000 redline, with very short dwell times, and a wasted spark ignition) these coils have very fast charging characteristics so they can handle the 550's 7500 RPM redline without breaking a sweat.

Other coils designed for longer dwells and lower charging currents might have issues with weak spark at high RPM, plus might not be able to handle the duty cycle when being used in a waste spark situation where they have to fire twice as often as a fully sequential setup (firing only on power stroke).

[a1exander]

John how would this set up get wired on the (2,7) 355?

The electrical side on cars still baffles me not that I am a pro on the mechanical side.

[gothspeed]

Originally Posted by cribbj

Goth, in rereading your post and question, I may not have given an adequate response. I think your question really related to the (lack of) dwell time at high rpm due to the wasted spark ignitions on these engines, and whether this would adversely affect these coils?

Because of their OEM application (the Hayabusa has an 11,000 redline, with very short dwell times, and a wasted spark ignition) these coils have very fast charging characteristics so they can handle the 550's 7500 RPM redline without breaking a sweat.

Other coils designed for longer dwells and lower charging currents might have issues with weak spark at high RPM, plus might not be able to handle the duty cycle when being used in a waste spark situation where they have to fire twice as often as a fully sequential setup (firing only on power stroke).

Perfect! Yes my question was regarding the shorter dwell time related to the wasted spark on our cars. So as you said if the the coils can handle a wasted spark at 11k, then they should be just fine at a lower RPM .

e1exander, As far as I know, the ignition coilpack setup on the 2.7 is the same as the 5.2 ...

[cribbj]

Originally Posted by a1exander

John how would this set up get wired on the (2,7) 355?

The electrical side on cars still baffles me not that I am a pro on the mechanical side.

Peter sorry I wish I knew more about the 355's; I'm assuming you have dual ECU's on your car? One that runs the right bank (1/2/3/4 front to rear) and one that runs the left bank ( 8/7/6/5 front to rear)?

So with your firing order of 1-5-3-7-4-8-2-6, and rearranging the order slightly:

1-5-3-7
4-8-2-6

We can see that the paired cylinders for the waste spark ignition will be 1&4, 5&8, 3&2, and 7&6.

So the coils for 1 & 4 will be wired in series, and that pair will go to the first ignition output on your right hand ECU (standing at the rear of the car), then 3 & 2 will get wired in series, and that pair will go to the second ignition output on the right hand ECU.

Same will happen for 5 & 8 and 7 & 6 for the left hand ECU.

If you have only one ECU that runs both banks, then it'll be 1&4 on the first ignition output, 5&8 on the second, 3&2 on the third, and 7&6 on the fourth.

I think this is correct, but I'd need to get "up close & personal" with a 355 for a few minutes to be sure

[bretm]

Originally Posted by cribbj

...the expensive 4:1 polyolefin McMaster stuff, for my own limited harness work, and it's holding up well too.

Good to know. Thanks, John.

[a1exander]

Thank you.....I shall have a look at it.
It is 2 ECUs as you said.