Coil-on-plug retrofit? [SOLVED]

D

dxh

Addicted to exxes since 1984
Anyone have experience using coil-on-plug on their exxy Lampredi engine? I'm assuming the use of a retrofit kit, such as the Hondata Coil Pack Retrofit - CPR, which wold probably require a certain amount of additional 'customization' to work with our cars.

Any thoughts as to why this would not be a good idea?

Thanks.

EDIT to answer my own question: After further research, these types of kits assume/require an ODB-1 ECU, so that's a non-starter.
Oh, well, it was a nice idea...
 
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Conversion to wasted spark ignition is very possible. Start with the Miata NA/NB ignition system as an example. it used a "modified" distributor to trigger two ignition coils. Each coil fires two cylinders 180 degrees opposite.

~Hint, a modified Bosch EI distributor can do this..

Bernice
 
I have thought about this.

I would start by looking at what they used on the punto turbo. It had a fancy crank sensor that replaced the distributor and a 4 output coil pack. I am sure it will use the ECU in between as well, but not sure about the details. I bet you could use any aftermarket ECU for that if you don't want to use the punto ECU (and I am not sure you would). But it this is close and has been done. I am sure if you wanted you could swap this to a COP system.

Not sure what they gain would be over the coil pack, but I am sure it could be done.
 
In addition to adopting a stock production (OEM) ignition system to your requirements, there are standalone ignition control modules that are designed to do this. The biggest advantage with a standalone aftermarket unit is it can be fully programmed (e.g. timing curve, total advance, etc), which the OEM units cannot. Being standalone means they do not require a ECU or such....they are a completely independant add-on system. They are available for coil on plug (or coil near plug) with "smart" or "dumb" coils. Lots of coil choices can be used with them. Typically they will require a crank trigger to establish the timing; some include the trigger setup, others can use any of several trigger options (including adapting the existing distributor, although that isn't the ideal way to do it). These are small modules with a basic wiring harness and intended to be installed as a replacement for any other ignition system. So it would work for your situation. You should be able to find choices in the $300 to $500 range, and up depending on specific features and brand name. Search for a "standalone COP ignition system".
 
It occurred to me, for the price of a standalone ignition module you could buy a MicroSquirt ECU (around $350) and only use the ignition side of it. Then if you want to go to a programmable EFI system later the ECU is already there. The MicroSquirt does not include coil drivers so "smart" coils are required (there's plenty to choose from). And it offers full programmability of the ignition.
 
Bosch Motorsport coil on plugs works very well as they can flex. I have them mounted on an alu plate. I have the MaxxECU Race unit wich is overkill for ignition management only, but the little brother MaxxECU Mini would handle it just as well and is much cheaper
IMG_20200505_105618~2.jpg
 
GM LS coils could work well with a flex plug wire. TonyK used the OE Marelli 500 COP units with a flexible lead on his 500 turbo swap.

GM has several different coil families which would be more than adequate for this application.

Controlling them is the question of course but all after market engine management could fulfill this.

I am intrigued by @Rupunzell Bernice’s comment about modifying the Bosch distributor to provide a signal every 180 to fire the coils. Care to elaborate? Thanks
 
kmead said:
I am intrigued by @Rupunzell Bernice’s comment about modifying the Bosch distributor to provide a signal every 180 to fire the coils. Care to elaborate? Thanks
Click to expand...
Very old idea never cultivated. Make a four hall sensors on a modified cap to fit the Bosch distributor. Make a rotor with two magnets to trigger two of the hall sensors at once, this produces the trigger signal to fire one of the two coils used in a wasted spark EI system. The electronics and mech bits related to this lash up is not too complex and easy enough to do. Advantage to this, the Bosch advance curve and all is retained, the distributor is no longer subjected to the stress of HV as the distributor is essentially running non-contacting electronic bits..

There are a number of coil on spark plug units that can be used..

Side note, Saab-Scania patented the uber high energy smart EI pack that sits on top of the spark plugs. This is known as the DI cassette. Inside is a lot more than just the high energy ignition (50+ KV per spark plug), The ECU controls spark timing per engine rotation degrees as needed. Second part of the DI cassette, the spark plugs are used as knock sensing by ionization of the compressed air/fuel mix. If detonation is detected at any time, the ignition timing is adjusted as needed or no ignition at all due to detonation. Saab-Scania was not the first with this idea, they did get the idea to work in production:

US4648367A - Method and apparatus for detecting ion current in an internal combustion engine ignition system - Google Patents

The invention relates to a method for detecting ion current in an ignition circuit included in the ignition system of an internal combustion engine, where a measuring voltage is applied to the ignition circuit and a measuring device is utilized for detecting ion current possibly present in the...
patents.google.com

This is FAR more accurate and reliable than piezo detonation sensors that "listen" for detonation. This is one of the turbo engine management features of the Tronic ECU that allows absurds amounts of boost with few problems.. The Tronic software is open sourced allowing those with the ability to tinker with the ECU software at will..

Bernice
 
As was discussed in the "turbo" thread, utilizing a modified distributor as the ignition timing source will work but is not nearly as accurate as a crank trigger. Good enough for a early design production engine management system like on the stock UT back in the day, but very primitive (and imprecise) for a modern management system. It really doesn't make sense to make a big step backward after upgrading to a superior system that can be accurately programmed. Especially considering how easy it is to use a proper crank trigger setup. However each project can have different goals so anything is possible. ;)
 
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