NON ZR-1 Technical Help needed

[XfireZ51]

Scott,

I think what you have discovered is very similar to what we did in adapting the LSx coils on the LT-5. In our case, we converted what was grounding the coil by the Ignition Module into a triggering signal. The signal was ~.4v and it was inverted.

Originally Posted by scottfab

OK Kurt, Here is what I've found.
To start with the pdf schematics for the 2002 and 2004 are more of a logical diagrams and do not contain all actual specifics of the circuit.

Having said that and after examining both coils I now know enough to say the 2004 circuit uses a positive transition pulse to turn the coil (create HV at the output).
The 2002 circuit uses a negative going pulse to do the same.
An example here shows what the two look like. First is the 2004 pulse
the second is the 2002 pulse.


What does this all mean? It means just changing the wires in the harness and shorting pin 2 to pin 4 will not work.
What has to happen is an inversion of the pulse on each coil input from the ECM.
This can be done by adding a transistor (and possibly other protective components) to each coil. I can furnish a rough schematic of this.
Sorry I know this is not what you were hoping.

BTW the output voltage of the 2004 coil is MUCH greater than the 2002 coils.

[XfireZ51]

Oh 1 other point. The LSx coils required a 20A power circuit for each side.
Ran that direct from battery w relays for switching ON. Think I still have the harness for that.

[scottfab]

Originally Posted by XfireZ51

Oh 1 other point. The LSx coils required a 20A power circuit for each side.
Ran that direct from battery w relays for switching ON. Think I still have the harness for that.

That must look pretty interesting. I think in this case it should be possible to invert the signal directly and to do it with as few noticeable appendages as possible. There are 12 coils and the wiring is already set up for individual coil driving. The current load is easily handled by the existing wire size. The fuse may need to get bigger.
We'll see.

[limey]

As agreed, i've paid my $500.00

Thanks for the job well done.

[XfireZ51]

Originally Posted by limey

As agreed, i've paid my $500.00

Thanks for the job well done.

So can we see this beast running w the VW coils installed?

[limey]

Sure you can, once i get the harness made, right now it's a rigged up harness and only one coil firing on the 4 pin VW.

[scottfab]

Based on numerous circuit simulations I predict NO dwell issue what so ever. The Ferrari wire harness is MUCH more stout than the ZR-1 and can most easily handle the current. And I suspect the fuse adjustment, if needed, will be trivial.

[XfireZ51]

Excited to see what you have done here.