noise filter setting _ is this correct ?

[flowbench]

Hello !
Finally I got my 350 Chevy running. ITs got a HEi 8 pin ignition, MS2 , on a 3.o board. Most times I do have serve kickback during starting and very, very few rpm-spikes
during cruising. See attached logs. I did set the "skip pulse" higher to "8" which didn't help. I started playing with the noise filter setting and don't know if my ideas about how to use this are right. Checking other posts on this subjects didn't answer my questions.
To give me a better understanding on this: At the log you can see that the rpm-spike at cranking speed is about 500msec long and occurs at a cranking speed in the aerea of about 120rpm. So I set my filter curve to that point. At 2000 rpm when occasinally I get these spikes they last only 120msec or so, so I adjusted the curve to that value. Am I on the right track ? It seemed to help only a little bit... still kicking back. Then I started playing with the "Tach period rejection" . To get this right, I need to calculate the shortest time between ignition events and stay below that in my settings ? Correct ? So, at 6000 rpm the crank turns 100 revs per second and we have 400 ignition events per second, so they are 25milliseconds apart from each other ? So should I use a time setting of about 20 milliseconds or so to stay below 25 ? And what about the percentage ? Would 30% be a reasonable value ? Sorry for all this stupid questions and assumptions but I couldn't find anybody with a similar problem on a small block chevy. Thanks !

[Rick Finsta]

At 6000rpm you have 20mS between any two valve events on the same cylinder (say from IVO to IVO on the next cycle), meaning you have eight ignition events during that time. The means 2.5mS between ignition events.

RPM converted to seconds per revolution is (1/RPM)x60 and that's crank revs so for a full cam cycle you multiply by two.

[flowbench]

Thanks Rick ! I will change my settings and see what it does. Any experiences with the percentage-value so far ?
Thanks a lot, cheers Cornelius

[slow_hemi6]

On hei8 it is meant to crank on the modules base timing of 10 degrees so you should not be getting any kick back caused by MS as MS is not controlling timing. Do you have it set up for a constant 5v on bypass?

[Rick Finsta]

Honestly I never dug into the noise filter settings since I haven't had issues. I just wanted to point out the math error to hopefully point you in the right direction.