Old thread, but I had similiar question as Brobullet. Been decades since I've been "just a kid". In some ways may think and act like one. Figure that I would bump the thread up for others.

First wasted spark coils I remember were on GM quad 4. This may have been in the days before PBCs were substituted for another cooling oil. The replacement coils probably aren't as good performance wise. The 4 post coils had 3 terminals, +12 and firing terminals for each pair of cylinders and the 4 spark plug wire terminals. There were also 2 post coils. I doubt 2 individual smart coils would be as good performance wise either. They are sized to charge (probably around 40% duty cycle) for the time between an individual cylinder firing so in a wasted spark setup would just be charging half the time.

With driver circuit inside ECU, I think the old canister style coils may be better than the LS type smart coils. I'm interested in what you all smart folks think. Will I need to use some kind of snubber in the driver, etc?

Mod: link to old thread.
https://forum.allaboutcircuits.com/threads/wastespark-to-coil-on-plug-conversion.164219/post-1444724

 

@1drew1 Welcome to AAC.
Since you have questions and are interested in what the originator of this thread may have done; note that they haven't been here in 6 years. It's not likely they will be back. So it's a better idea to start your own thread. Be specific.
Tell us what you have.
Tell us what your goal is.
Tell us what your skill level is.
Tell us what your budget is.
That's just to name a few suggestions.

 

Having worked for a company which made automotive modules, including electronic ignition modules, I recall that the ignition is a key component in the emissions compliance system, and as such are heavily managed by government regulations. Therefore, the overall spark ignition is designed to be difficult to be tampered with.
For instance, how would one know when to advance/ retard the ignition timing, in response to engine data provided by myriad sensors?

 

tonyr and schmitt trigger, thanks for reply. Hoping that even if Brobullet doesn't read this thread, maybe some like him will. Thinking that things are picking up and many young folks are looking into more than just physical performing but into things developing their brains.

My skill level comes from being an industrial mechanic, mechanical repair, experience in manual machining, mechanical improvements and development, electrical troubleshooting, etc. Education, it took me over 20 years to get an associate degree in Mech Eng Tech. I did win an award during those years, mid 1980s?, a state competition in working models category. It was a color sorter which would detect objects of the wrong color using an opamp comparator.

The skill level of my buddy who I will discuss a possible programmable ignition with is: years ago he was a painter in an industrial plant. I first met him, in late 1970s, through his Stepfather, an industrial engineer. The company where I was working, reconditioning carbide inserts, was trying to get work from the Stepfather's plant. My boss had me make a tool to hold carbide inserts to do internal deburring of tubing cut with a chop saw. Afterwards he introduced me to my buddy, a high school student who needed a hydraulics lift kit put in his Monte Carlo. We worked together on this project, involving fabrication and building a circuit letting his 12V alternator charge two batteries that ran his pumps in series. He started painting Harley gas tanks at home, After his plant closed, he built a shop on his parents property to do body work and paint cars. He did good, getting into used cars, mechanical work, restorations involving body, drivetrain. and electrical. Restorations involve a 70s model 911, which has now ended up in Germany, a Packard, recently some kind of German Jeep. Cash for Clunkers and covid hurt his business so that now he works by himself. He gets help as needed from several. He is known as the local guru on Porsche 914s, Weber Carbs, D Jetronic and L Jetronic fuel injection.

Pretty sure there will be another involved that comes and does electrical work on the restorations. He is sharp, I think a retired EE. He has a 914, with motor he rebuilt running D Jectronic that is beautiful and fast.

Unless told not to, I will share comments and suggestions.

The goal is to get a strong running reliable 914 motor. This is basically a VW aircooled Type 4 motor. Crankcases are different from VW and in 2.0 liter versions the Porsche cylinder heads are different. I'm saying low budget, a repair job with performance and reliability improvement. This is because he honed a cylinder that had scratches and since a bad head he is repacing with the 2 liter heads. No busting open the case, which has a performance cam. He has venturis for the Webers that would work good with this cam. This motor, per case number, began as a 1.7 liter, but has 96mm cylinders making it about 1.92 liters.

Potential problem is distributor, Bosch 009 mechanical advance which comes in full advance at around 3000 RPM. Some prefer the 050 distributor, full advance at around 3500 RPM. Both are hard to find now, but there are China copies of 00. With initial timing set to give 35 degrees full advance there is great power from around 4500 up. There is full throttle spark knock with the individual turning length from Webers and SSI heat exhanger And Bush exhaust tuning length at 3500 to 4000 RPM. Felt it on the road with these motors and verified with Perfomance Trends engine software showing timing needs to be retarded at these RPM. No problem at light load, just when on the pedal.

Electromotive had a great programmable ignition box. Seen it run on 911 Porsches on race track. I think covid got them since they are out of business. I liked the Electromotive TEC II ignution injection box that I got years ago. Why can't we use a microcontroller fed by a trigger wheel to make our own? I bought the shop manual for the 924 turbo that my wife had which gives timing changes for pressure, temp, etc. Not an expert, but I have done some of the C/C++ programming on an Adafruit Arduino with grandkids.

A microcontroller sounds cheap, but trigger wheel, coils, connectors, and sensors will add up. His electronic guy would be high priced in programming, but would be helpful in questions like I ask. I guess I would program for nothing but learning and access to records, etc. Programmable ignition will likely end up a no go becuase of budget. Several months ago he had an instate guy that bought and had a northwest car towed that came and picked up his stuff after costs were mounting up.

I have questions, some kind of doide snubber to protect dc motor drivers sheild on microcontrollerfor the coils? Forget what they are called but 2 resistors in series with a center tap to reduce current and voltage from 5 V to 3.3 for microcontroller or maybe power sensors fron 3.3 on board? Don't know dwell time to put in controller for charging coils. Will suggest this coil, https://www.summitracing.com/parts/sum-850617. Wasted Spark by 4 individual coils firing 2 at a time. As far as programming, got to learn using interupts and Classes and Constructors. Likely will have to build simmulators for trigger wheel, sensors, and mayber bulbs to simulate coils. As you see my ignorance, I barely know enough to be dangerous. But yet will probaly run by my buddy's shop to discuss after a doctor's appointment on Tuesday. .

 

Unless you live in an area that demands yearly emissions re-testing of vehicles, or are producing systems for the mass market, meeting the emissions targets will not be the problem.
But if you live in a ...(Comment removed)

 

MisterBill2, think it will be OK as far as emissions are concerned. Over 50 years old so OK as far as Feds and no yearly checks here. Like many this 914, came with Bosch Injection. but it has been done away with. The Webers and centrifulgal advance dstributor are not stock.

 

Did not visit but short conversation with shop yesterday.

Looking for stuff found Pololu, in NV, US made products. Their opto coupled SSR high amp card looked promising but the 1ms rise and fall may affect timing. They have some great H bridge motor controller that may work.

 

MisterBill2, think it will be OK as far as emissions are concerned. Over 50 years old so OK as far as Feds and no yearly checks here. Like many this 914, came with Bosch Injection. but it has been done away with. The Webers and centrifulgal advance dstributor are not stock.

The TS is fortunate! There are areas where there is muchles personal freedom.