Logic vs. Stepper Ignition Options

[lugnuts]

I recently discovered a few ignition modules that will not work with Logic ignition outputs (mine use a 255 Ohm protection resistor instead of 510 Ohm. I was able to get the car running using the Stepper outputs and Dual-Out Mode (which with individual coils made for some interesting wiring).

I'm wondering:

What is the max allowable output from the Logic ignition drivers?
I.E. - is it ok to request less than 255 Ohm resistors on my next batch of boards? Will it be reliable?
I always get 4+4 for ignition configuration on my boards.

In regards to the stepper, how reliable are the stepper chips?
And what happens when I "upgrade" the firmware and discover they changed something in the water pump setting and I have no ignition. (speculation based on what seems to be endless changes and firmware revisions)

Thanks, Kevin

 

[rob@vems.co.uk]

The logic drivers have a very small output current - its a direct feed from the FET driver.
Stepper chips are reliable enough, take a look at Hilly's setup

The loosing spark problem occurs when there's an upgrade we'll have to have a collective effort to fix it, there was a change from pre 1.0.73 which changed the outputs, but thats not been repeated since.

[PeepPaadam]

I consider stepper outputs much better for logic level coils. They also give much stronger spark on VAG active coils.