Running a TIII coil pack off the 8V distributor?

[turbovanman²]

Ok, been thinking, bad idea I know but a coil pack works by firing each pair of cylinders at the correct time hence the reason why you have waste spark. NOW, what about hooking the coil pack up to stock 8 valve distributor, IE instead of the coil, you hook it up to the coil pack. The only issue I could see is trying ot figure out how to split the signal up so both pairs don't fire at once on the coil pack?

[Frank]

Coil pack and distributor are based on different sensor and different computer drivers. It wont work, nor any combination of them. I could type up an explenation, but I wont boar you unless you want me too.

[turbovanman²]

Its BORE,

I realize the differences but the computer does the work for you. If you hook it up, it will fire. Just thinking out loud,

[Frank]

Ok... sounds like I need to do some explaining.

Coil pack setup from the TIII cars first requires a 5spd tranny. Specifically the 568 with the crank sensor. This setup provides the computer with precise crank position so that computer decides which coil pack it needs to fire and when. There are two ignition drivers from the computer for this setup. Basically it fires 1/3 at the computer calculated timing position BTDC and then 2/4 at the computer calculated timing position BBDC.

Now there is a few other things with this... While there is mechanical base timing advance with the DIS setup, part of what allows the spark to fire is the close proximity between the node on the cap and the rotor. The computer's calculated timing preference is just an advance to the signal that is sent to the coil. While the intial signal from the computer (minus the advance to the signal) is just the HEP signal, it doesnt provide precise crank positioning like the TIII setup does.


Frank

[turbovanman²]

I knew that, just figured there might be an easy way but I guess I'll stick with plan A.

[Frank]

I guess I'll stick with plan A.

Good idea.

[85lebaront2]

Hey Frank, how about using an Electromotive crank triggered system? Could that work, it normally uses GM style coil packs, 2,3 or 4 as needed.

[turbovanman²]

Wow, never realized how close the intake sits to the engine, some intake work is really needed,

[Frank]

Hey Frank, how about using an Electromotive crank triggered system? Could that work, it normally uses GM style coil packs, 2,3 or 4 as needed.

Well only if you are using a STALO setup. The TIII computer uses a special pattern of nicks for determening degrees and as far as I know rather unique to the TIII and was rather weird.


Frank

[turbovanman²]

Well only if you are using a STALO setup. The TIII computer uses a special pattern of nicks for determening degrees and as far as I know rather unique to the TIII and was rather weird.


Frank

But that doesn't matter, a coil pack is fired based on the computer so any computer you use to drive it will have the advance etc either built or you what you programmed.

[Frank]

But your missing the point. The computer has different outputs depending on the type of ignition. The computer has also different inputs depending on the type of ignition. In addition, the code inbetween looks at both the input and the output to run it. If you

Trust me...

[turbovanman²]

But your missing the point. The computer has different outputs depending on the type of ignition. The computer has also different inputs depending on the type of ignition. In addition, the code inbetween looks at both the input and the output to run it. If you

Trust me...

I do but your missing the point. Your saying that the coil is the issue here for output, its not. The computer triggers it using inputs. If you use a TIII computer then yeah, its an issue but using something else, you can program it anyway you want, you can even use a V6 coil pack if you want. I did that on my friends R/T, used a V6 coil pack to get her running as his 4 banger one quit.

[Austrian Dodge]

btw: how does that crank sensor look like on those a568 r/t trannys? is it worth to modify my a568 tranny or better to bolt a trigger wheel onto the UD pulley?

never seen this before, so i'm not able to determine which route to go is easier as far as installation goes

[Frank]

Do I need to draw it out for you? hehehe

The coil pack has 3 wires. A common hot wire and two computer triggered wires. The first wire triggers cylinders 1 & 3 in a waste setup. The second wire triggers 2 & 4. The computer/code fires one of these wires depending on where it falls on the crank measurement. If you are at 25degrees advanced, then the 1/3 will fire 25degrees before TDC on the crank. Cylinder 2/4 will fire 25degrees before BDC on the crank. If it were a human it would say, I know I am at this angle and I need to send the signal to my first (or second) coil pack because that is what I calculated.

The distributor system is different. Its computer uses an ambiguous ignition event setup. The computer has only a rough idea where it is really at in the crank evolution. The sensor just says hey, this is where you are at now, guess where you need to fire next. It just sends a signal out to the coil and lets the mechanical distributor line up the rest of it to send to the right cylinder.

Another reason not to use a single section of the coil pack in place of the standard coil, is it is not designed for the higher frequency of having to fire another set of cylinders during the same set of revolutions. The coil's inductance field is designed to discharge at a certain rate for a certain voltage. If you cut its designed discharge rate in half, you dont get the full effect. However that is not what you asked... just extra tid bit of information.


Frank

[Frank]

btw: how does that crank sensor look like on those a568 r/t trannys? is it worth to modify my a568 tranny or better to bolt a trigger wheel onto the UD pulley?

never seen this before, so i'm not able to determine which route to go is easier as far as installation goes

Running of the flywheel is nice. This is because the increased diameter of the flywheel compared to a pulley allows for cleaner signal. This is because a gap/window on the flywheel is only say 5 degrees compared to 15 degrees wide. Of course those numbers arent nessecarily true for our TIII engine, but it is farily accurate. This is because VR and Hall sensors require a window/gap of a certain size to properly form the signal that the computer needs.

In addition to this, the trigger pattern for the pulley would have to be a custom make since almost all custom pulleys out there are there use the standard positioning or an EDIS positioning. The standard positioning uses a 180deg for 4 cylinder, 120deg for 6 cylinder, 90deg for 8 cylinder, etc. That is for a batch setup. If you want full sequential, you will have to have a cam sensor with a signal window near cam TDC which indicates a 'home' signal so it can distinquish which of the two revolutions has cylinder 1 at TDC. The EDIS setup uses a 36-1 wheel and uses a waste/batch setup, however that is another writeup for another time.

So yes you could create your own sensor and wheel setup, however it would be custom, and because the TIII setup is so special in its design, it might need a certain shape and level of signal that a custom wheel might not provide without some fustration and work to clean it up and really make it stable. Someone has in the past moved their sensor to the crank for an auto setup, however I dont remember what issues they saw other then the stupid pattern stuff.



Frank

[turbovanman²]

btw: how does that crank sensor look like on those a568 r/t trannys? is it worth to modify my a568 tranny or better to bolt a trigger wheel onto the UD pulley?

never seen this before, so i'm not able to determine which route to go is easier as far as installation goes

It has been done. A guy on TD did it as he wanted a TIII auto as he had a leg problem and/or so his wife could drive it. He said the crank signal was at X degrees, put the front crank at X degress and it worked perfectly.

[Frank]

It has been done. A guy on TD did it as he wanted a TIII auto as he had a leg problem and/or so his wife could drive it. He said the crank signal was at X degrees, put the front crank at X degress and it worked perfectly.

Not true. He had to have a wheel made with the same pattern as the flywheel for cuts. I remember him posting on there with some other issues.


Frank

[zin]

DOH! There was a lot more to this post I didn't see, sorry if I'm covering old ground with this...

Ok, here I go stirring the pot.
I'm just ignorant/informed enough on how coil packs work to suggest the possibility of using a non-mopar coil pack, maybe a GM unit from a Saturn or something. Because my wife drives one (a Saturn), I know that while they do use a crank sensor, they don't require a cam sensor, which would suggest they don't require a high-res signal. Additionally, as I understand it, the ignition part is self-contained in the unit, and the advance is accomplished via the computer sending a signal to the coil pack to advance/retard the timing. This might do what Simon would like to do without the need for a crank trigger, since he just wants to fire the coils, and not use the advance/retard feature of the coil pack. If it will work, there might be a way to use them in place of the coil/cap/rotor, which is what I'd like to do. Thoughts?

Mike

PS Simon, I'm still working (slowly) on getting a 4-speed auto in the Omni, looks promising so far.

[Frank]

I think the issue is the computer doesnt tell the coil pack how much to retard advanced. It is just accomplished by just when it send a signal. the only big difference in this concept is the EDIS design where the computer tells the EDIS module back how much to retard advance its signal that it tells to coil pack. But in that case also, the coil pack is still just a dummy.


Frank

[86Shelby]

So Frank, what you're telling me is that I could use a slightly modified old dual point distributor to run a coil pack.... J/K