Coil Dwell Scoped, Seems odd

[psucrash]

So after several years of guessing at my coil dwell time I finally bought a current clamp for my O-scope. Now I need a little help interpreting the results.
According to my scope to get the maximum charge it looks like I should have my dwell set just over 6mS. That seems high to me, especially since I have been running it at 3.5mS dwell for a long time. Although I do experience some ignition issues at 22+ psi of boost that may be blow-out.

Coil Pack is Accel #140018
Ignitor is MSD DIS Dual Coil Ignitor #6302
Current clamp is set at 1mV/100mA but that doesn't seem to correspond to the waveform at all.

I contacted Accel and the specs for the coil are as follows
Primary resistance: 0.452-0.499
Secondary Resistance: 10250-12550
Primary Inductance @1kHz: 6.0-7.3mH
Secondary Inductance @1kHz: 41-51H
Turn Ratio 85:1

I measured the primary resistance and have 0.7 Ohms. Although checking my notes it was also 0.7 about a year ago. That seems out of spec to me, but who knows??

Here is what I am seeing with dwell set to 8mS @1k RPM. From this I think my dwell should be set at about 6mS. I know the battery dwell correction is the reason the graph doesn't show 8mS dwell. Perhaps that needs some adjustment too.
Advice, Input, Suggestions?

[dave]

The first part of the curve where it's linear, that's current in the inductor building, nearly all of it will make it to the secondary coil. the second 30% where it goes up exponentially looks like saturation. A lot of this extra energy won't be transferred but there's enough current limiting that it doesn't look like it hurts anything to try and get a little extra out of it. Then it flattens off, I suspect any additional time it will just stay flat up there. This is limited by the circuit and coil resistance and basically just acting like an electromagnet, you are adding no additional energy to the spark. It is wasted energy which will just heat your coil. Most transformer timing I've worked with won't round off like this, it'll take an even harder turn up until it looks like a short circuit.


So interpret that how you will.. it explains why 3.5mS is a common setting. But personally I don't see the harm in going up to 5, looks like the current doesn't go out of control. 6 you could try but prob better off looking at different plugs/gap if 5 doesn't fix your issue. anything higher you're just needlessly heating the coil and switches.

[psucrash]

I do understand the concept. Just looking for advice on my results.
Thank you for the reply! Gap is currently at .028" so I'll give 5ms a shot.

[psucrash]

Dwell set to 5ms and I worked on the battery correction to have it match ideal dwell. So far so good, but without getting back in the dyno it remains to be seen