I'm having issues now coming off idle where the ignition coil dwell time will drop from 15mS to 6mS and cause a misfire. It shows up in hotter weather as the coils become less effective with greater temperature.
Stock dwell time is 15mS at idle and 2.5mS at redline.
Here's the dwell time I was running:
Dwell time: 10,000 uS
Dwell dynamic addition: 30%
Max dwell time: 12,000 uS
Min duration of discharge: 3,000 uS
Max rpm for dwell by lobe: 600 RPM
I made some adjustments to try to fix the issue and this was the result.
Dwell time: 12,000 uS
Dwell dynamic addition: 30%
Max dwell time: 14,000 uS
Min duration of discharge: 5,000 uS
Max rpm for dwell by lobe: 900 RPM
It increased the average dwell time below 3000 RPM from 12mS to 14mS, and slightly increased the lowest dwell time from 5.5mS to about 6.5mS.
However it caused a decrease the dwell time near redline from 4mS to 2mS.
I realize now that's due to the change in Min duration of discharge from 3,000 uS to 5,000 uS.
At 8700 RPM, it has to fire a spark every 6.9 mS. If I take away 5 mS for "duration of discharge", that leaves only 1.9mS of charge time.
That starts to have an effect at 4200 RPM in the first graph and as early as 3200 RPM in the second graph!
I also noticed that bumping up the Max rpm for dwell by lobe to 900 RPM caused it to struggle to recover if the RPM ever dropped that low.
I think it's because it removes the ignition advance and it drops from 5 degrees advanced to 0 degrees.
Cranking RPM is ~250 on my bike so I figured 300-400 is a good range.
That way it retains an extra long dwell time during low voltage cranking to help with hot starts, but then quickly jumps to it's running timing to get the RPMs up on startup.
I'm going to pull down the max dwell time to 12mS because I don't like how it sometimes goes as high as 18-20mS at idles now.
I'm going to try another change to see if I can resolve this issue.
Dwell time: 12,000 uS
Dwell dynamic addition: 30%
Max dwell time: 12,000 uS
Min duration of discharge: 1,000 uS
Max rpm for dwell by lobe: 300 RPM
The manual is translated into English and not everything is super clear.
I don't fully understand these two settings:
Dwell dynamic addition - dwell addition to compensate uneven engine running at low RPM [%].
Compensation - frequency compensation of the phase error of engine position inputs. The phase error is due to the frequency dependency of trigger level of input and the delay that occurs when processing the input signal. The phase error is mainly dependent on the number of lobes of the pickup system of the motor position.
I have them set at 30% and 11 respectively, but I really don't know what they do, especially "Compensation".
EDIT:
The dwell time seems to drop to just under 1/2 of the "Max dwell time" when I crack the throttle.
I was seeing it drop to 5.5-6.0mS with a 12,000uS max and 6.5mS with a 14,000uS max.
The stock system looks like the coils only needed 8-9mS at idle, so 2x8 = 16,000uS. Add a little extra and go with 17,000uS max.
I'm going to increase the Min duration of discharge to 4,000uS for 3mS dwell at 8500.
This helps reduce the dwell time at midrange, as this will limit dwell time to 11mS at 4000 RPM.
When I looked at the load/heat in the coils, it would actually peak at 4500-5000.
Stock timing at 5000, it charges for 8mS every 12mS or 67% of the time. At idle, it charges for 15mS every 50mS or 30% of the time.
I can afford to drive them longer near idle without worrying about heat produced.
Reducing the Max rpm for dwell by lobe to 300 was an improvement over a setting of 900, and possibly an improvement over 600.
I'm going to try the following:
Dwell time: 12,000 uS
Dwell dynamic addition: 30% (I think this setting adds up to 30% to the dwell at low RPM)
Max dwell time: 17,000 uS
Min duration of discharge: 4,000 uS
Max rpm for dwell by lobe: 300 RPM
EDIT: Here's the results of that test.
Almost there! Still a bit of off-idle hesitation, but less than before.
I'm satisfied with the high RPM dwell time.
With gas being high, I'm not going to go out of my way to make sure I hit those RPMS for logging purposes anymore.
I'd like to lower the average dwell time at idle, while bringing up those 6.5-7mS points.
I just did the math and at 300 RPM, if the dwell time is the length of the lobe (20 degrees), it's only going to be 11mS of dwell time!
300/60 = 5 revs per second or 200mS per rev. 200 * 20 / 360 = 0.011.
I'm actually shortchanging my dwell time at cranking RPMs, And here I thought I was helping.
That explains why setting that value to 900 RPM was so terrible as it made the dwell time 3.7mS.
I'm going to try the following:
Dwell time: 11,000 uS (Hoping to lower the average dwell time)
Dwell dynamic addition: 30% (Still not sure how this affects things, but 30% is the maximum allowed value)
Max dwell time: 20,000 uS (This seems to affect the minimum values seen)
Min duration of discharge: 4,000 uS (Limit mid to high RPM dwell time)
Max rpm for dwell by lobe: 100 RPM (Effectively disabled since cranking speed is ~300 RPM)
EDIT: Here are those results.
I did bring down the average dwell in the 2000-3500 range.
Meanwhile the values around idle have increased, with the minimum climbing to about 7-8mS!
The hesitation was improved, but still present.
I was hoping for 9mS, but I'll take what I can get.
20,000uS is the maximum value the software will allow for Max dwell time, but increasing that did seem to improve things.
Ignore the <2mS values. Those are from messing with the kill switch while it's running and aren't real world values.
Cold (well, cool...it's 75F in my garage) and hot starts are good.
The coils are still being driving a bit hard in the 2500-5000 range (as compared to stock), with peak heat happening at 3500 RPM.
But the values I rode with last year drove them a bit harder in that range and they survived just fine.
About all I can do from this point (in order) is:
Try reducing the Dwell dynamic addition to see what effect that has.
Fix my grounding ignition to gain back 0.7 Volts I lost from my wiring.
Regap my plugs a bit smaller, and closer to stock gap size.
EDIT: Here are the results, this time only looking at 1000-4500 RPM as I'm fine tuning the lower ranges.
The values are shown as:
Red, Black,
Green.
Dwell time:
11,000 uS - 11,000 uS -
10,000 uS
Dwell dynamic addition:
30% - 15% -
10%
Max dwell time:
20,000 uS - 20,000 uS -
20,000 uS
Min duration of discharge:
4,000 uS - 4,000 uS -
4,000 uS
Max rpm for dwell by lobe:
100 RPM - 100 RPM -
100 RPM
This tells me the Dwell dynamic addition percentage changes at what RPM it takes effect.
Overall, the black settings seemed to respond best.
Green gave me a bunch of outliers in the 1500-2500 range that didn't show up with the black settings. No idea why that is.
It also drives the coils a bit less than stock in the 2000-2500 range.
Lastly, the additional dwell with green tapers off around 1000 rather than 1250 for black, or below idle speed.
I'm going to stick with the black settings and now focus on the wiring and plug gaps.
As seen in post #10 in this thread, the stock coils don't charge much more after about 8-9mS at idle, and that's where the black settings are getting me at a minimum!
There really isn't anything more I can do to improve the ignition dwell time at this point.
P.S. Ignitech stopped responding to my emails after I told them about my logging program.
I still recommend purchasing this unit, but I think I offended them through my work

.
I did notice that the unit has a built in hourmeter that gets sent back with the data packets somehow.
I hope to update my logging program to record that data as well.
Who knows what other data is sent back. Each data packet is 152 bytes and I only know what 14 of them are for!