Electronic Distributor Adapter

[90TurboVan]

This would allow you to use the dist. in the stock location without a cap, just a HEP. Would require the use of the Neon DIS coilpack, but would run without mods on stock electronics.

Is there any interest? I'm working on it right now so I have something to run my hybrid until i get MS on it. I can post a parts list, schematics, and code.

Just to clarify, you would connect the sense wires from the HEP and the ignition coil output from the computer to this adpater, which would then control the Neon coilpack. You would no longer need the stock coil, cap, rotor, wires, and such.

[turbo.shaft]

Quote:

Originally Posted by 90TurboVan This would allow you to use the dist. in the stock location without a cap, just a HEP. Would require the use of the Neon DIS coilpack, but would run without mods on stock electronics. Is there any interest? I'm working on it right now so I have something to run my hybrid until i get MS on it. I can post a parts list, schematics, and code. Just to clarify, you would connect the sense wires from the HEP and the ignition coil output from the computer to this adpater, which would then control the Neon coilpack. You would no longer need the stock coil, cap, rotor, wires, and such.

I would be very interested if it works reliably. Is there any way to use the cam signal on a 2.0/2.4 with stock electronics and fire the neon coil and ditch everything easily?

[jrbexhaust]

Yes. If you can make an adapter to go between the cam sensor, HEP, and coil packs no dist is needed for the old computers, you would have solved a lot of problems for people. I would buy one.

[rfb6435]

Hmm I convinced myself that this wouldn't work a while back.

The reason is that the old computer doesn't have the timing resolution to fire the coilpacks that accurately.

With a distirbutor you only have to be close and the rotor will take care of it by only sparking when it is in the right place. It is essentially a charge things up and wait for the rotor event rather than a "fire now" type of system.

-Rich

[90TurboVan]

The old computer does indeed have the resolution and power to fire coilpacks, but you'd have to modify the code and hardware of the computer itself to support two coils. What I'm talking about is a separate module that fires the Neon coils depending on what cylinder is on compression. It uses the stock computer's spark output to determine when to fire, sort of like a solid state distributor that can fire two coils. It could really be extended to complete COP. Btw, an ignition coil/distributor is a "fire now" type of system. The computer pulls one side of the coil to ground, and when it lets go, a spark will happen. The distributor just directs it to the proper cylinder.

You do not need a cam sensor to determine what revolution the engine is on. The HEP has outputs that are encoded such that they give an indication of all TDC's and a separate ones for #1 and #4 TDC. As much as I know about the Neon cam sensor, you would not be able to use it alone. You would need some type of crank sensor as well, and if you're using stock electronics, the module would have to emulate the HEP for the stock computer to understand.

I hope to have an '87? Turbo Z running on a Neon coilpack and stock electronics tomorrow if all goes well.

[rfb6435]

Quote:

Originally Posted by 90TurboVan The old computer does indeed have the resolution and power to fire coilpacks, but you'd have to modify the code and hardware of the computer itself to support two coils. What I'm talking about is a separate module that fires the Neon coils depending on what cylinder is on compression. It uses the stock computer's spark output to determine when to fire, sort of like a solid state distributor that can fire two coils. It could really be extended to complete COP. Btw, an ignition coil/distributor is a "fire now" type of system. The computer pulls one side of the coil to ground, and when it lets go, a spark will happen. The distributor just directs it to the proper cylinder. You do not need a cam sensor to determine what revolution the engine is on. The HEP has outputs that are encoded such that they give an indication of all TDC's and a separate ones for #1 and #4 TDC. As much as I know about the Neon cam sensor, you would not be able to use it alone. You would need some type of crank sensor as well, and if you're using stock electronics, the module would have to emulate the HEP for the stock computer to understand. I hope to have an '87? Turbo Z running on a Neon coilpack and stock electronics tomorrow if all goes well.

Perhaps I was confusing the idea that the DIS setup can fire the plugs whenever it wants to where the distributor is dependant on where the rotor is. How accurate are the stock electronics without the rotor enforcing things?

I would be much much more interested if your setup did away with the distributor completely. Whether or not I run the cap and rotor doesn't matter that much to me if I still have to spin the distributor base and use a HEP on my 2.4 conversion. There are pleanty of nice epoxy coils out there that can sit in the place of the neon coilpack on 2.4 and hybrid applications and I am not that worried about spark loss in the distributor cap. The challenge is spinning the dist from the cam in the first place.

I guess it might help clearance issues in a hybrid setup though.

Unfortunately decoding the crank trigger and cam sensor is a bit more complex and I don't think our computer is up to that. If the computer is capable and somone is interested in writing the code that would be awesome.

Keep us informed on how your setup works!

-Rich

[Shel-Game]

On our cars, the rotor is in contact with the terminal in the cap for about 40deg. The computer controls the timing within this range.

It's the same on the old points-type distributors. The points control the actual firing of the spark, the cap/rotor just decide which cylinder gets the spark.

[crazymadbastard]

the main problem we have is we only have one coil, so only one signal is sent.
My guess is you would be adding another coil output to the computer.
Also If you can figure out the first spark ,then you could build a circuit to figure out and count the spark events and alternate between coil one and two firing.

I ran into this at the srt4 forum:

Qwkslvrsrt - MSD Ignition/image036

[rfb6435]

Thanks for the clarification on my misconceptions of how the ignition works!

What is the advantage of running the coilpack other than not having the spark loss from the rotor to cap? I guess it would also be nice if we didn't ever have to replace the cap and rotor.


As a side topic:

Is it theoretically possible to use the crank trigger and cam sensor with the old electronics rather than the HEP? If yes we probably need a seperate thread for that discussion.

-Rich

[guidsm]

MS is your friend :-)

[Shel-Game]

Quote:

Originally Posted by rfb6435 Thanks for the clarification on my misconceptions of how the ignition works! What is the advantage of running the coilpack other than not having the spark loss from the rotor to cap? I guess it would also be nice if we didn't ever have to replace the cap and rotor. As a side topic: Is it theoretically possible to use the crank trigger and cam sensor with the old electronics rather than the HEP? If yes we probably need a seperate thread for that discussion. -Rich

I think it's possible. You'd have to lose a couple of other inputs, though. The HEP input has some specialized circuitry involved. So, you couldn't just plug an optical or other trigger into that. Also, different kinds of inputs might need a custom interface if some solid-state circuitry is required for it. I would be cleaner (with a SMEC) to simply redesign the entire power board for that application.

[90TurboVan]

Its definitly possible. You would not need to add any hardware for the 2.4 cam/crank sensors. The HEP is two hall sensors, and the 2.4 sensors are hall as well. You would need to add a driver IC for the second coil, and modify the code to decode the sensors and drive both coils.

My module decodes the distributor on the bench or when the car is running and it isn't controlling spark, but for some reason not during cranking when its actually controlling the spark.

MSnS-E is the plan guidsm, but I want to break my motor in before I try and get it to run on MS. I also thought some people might want to do the DCal thing with the stock electronics, and this would help with clearance.

[guidsm]

I understand, but now you can go whit MS and base cal ..i have put 4 different spark table for almost every setup. I will put shematic siagrma soon also.

[crazymadbastard]

Ok, how about this? using the second sensor in the dizzy to figure out which coil will fire, this is the same sensor for the injectors since they fire in pairs. hmm

[90TurboVan]

Maybe this will explain. If you were to put a scope on the two distributor sensors and the coil negative wire, you would get this:



The spikes on the coil negative graph are where the actual spark happens.

Obviously, you can determine TDC for all cylinders with just one of the sensors, but it could take a maximum of 4 revolutions of the crank to find #1. By using both, you have a max of 2 revolutions before everything is synchronized, and it makes it much easier to detect #2 and #3 TDC.

The advantages of DIS over coil/cap/rotor are less maintenance, more efficient spark, and the possibility of twice the max RPM because the ignition needs are shared between two coils.

As for the project, the Daytona started and ran on the Neon coilpack and my adapter today.