The subject pretty much says it all. I am putting together my spark table for MS and I already have down the time it's take for revolutions per given rpm. Regarding the spark flame speed during combustion, I have seen alot of conflicting info and nothing out there that goes into how its found.

I appreciate the help....

 

Good luck on finding that info...

Just by going with a different bore size, or a different heat range spark plug, would throw that number around big time. I don't even think there is a method you can find this "value" if that is what you are looking for in order to dial in the spark timing.

 

why do you need to know the flame front speed? only needs to be looked at when you are approacing huge piston speeds (>6000 ft/s) IMO. otherwise ignition can be calculated comparatively against stock/other setups and will need to be optimised on a dyno.

 

It's not a relevant data point. What your asking is dependent on too many variables beyond actual timing. Why do you want that information?

 

coming up with an initial spark map for MS. Also, I want to target a specific crank angle for ignition timing wise. Yes I know that I can go with a stock spark table, but this is for future reference. I already have it down to figure out the time is m/s how many degrees the crank will travel or how long a degree will take. In regards to the bore size, I would take the bore and size divide by 2. That should compensate for the any size difference, the problem is that I don't have a rule of thumb to go by for the spark flame front. I am find everything from 880 inches/second to 1 meter/second. I do know that the air/fuel ratio comes into to play, but as to what extent I am in the dark about.