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I remember long ago using a Suntune and hooking up the probes to all cylinders and watching the peaks on the scope, the timing betwen fires could tell a lot as regards dizzy drive and condition (wobble) even when you could not really feel it. Never really considered a lot of the science on how that affected performance only that it could.
Rolling roads in those days were take it up a quite local road and give it some
and unless it was your car the small changes were never noticed.
So how important is the timing of each individual spark per cylinder, anyone have a clue ? is 3 deg error OK ? based on standard 120 gate trigger wheel ? 6 Deg ? or is staggered in some way to optimise the firing of each cylinder.
Electronics wise is easy, you can actually measure the "jitter" on TDC, by jitter I mean you start a micro accurate counter on the start signal until the next start signal, do that over say 5 minutes at 3k rpm (steady state, no vac advance) you can pull a rough
Thats 15,000 recorded triggers some of which may be a bit early and some a bit late so the +/- limits can be determined and stored, the same information can be used, specifically across longer drives to map and normalise this jitter and have the software generate the fire signal after it measure a minus it can ad a delay to "normalise" the fire position to what it should be regardless of the jitter. If 2 trigger sensors were used one at TDC and one at 180 degrees it could be made even more accurate.
Big variable is how stable the engine is when at 3K rpm a thats also a tolerance to be compensated for.
Tolerance discussion is all I need for the moment, curves are a different story, with base value I can almost create a set of values to program ffrom a drawing in excel.
I know how much can be done in firmware but anyone a clue on what accuray limits are required in the real world, I am guess about +/- 1.5 deg is OK as most trigger wheels as 120 steps of 3 Degrees. moose549 ???
The actual solution would be to fit one of Mikes Dents ignition system and be done with it but I like an experiment or two now and again. and although i trust electrionics I certainly do not trust the off the shelf, assembled by the cheapest bidder low end solutions available at present. Plenty commercial drivers and coils available with proven QA, the trigger system and electronics however, very suspect.
Rolling roads in those days were take it up a quite local road and give it some
and unless it was your car the small changes were never noticed.So how important is the timing of each individual spark per cylinder, anyone have a clue ? is 3 deg error OK ? based on standard 120 gate trigger wheel ? 6 Deg ? or is staggered in some way to optimise the firing of each cylinder.
Electronics wise is easy, you can actually measure the "jitter" on TDC, by jitter I mean you start a micro accurate counter on the start signal until the next start signal, do that over say 5 minutes at 3k rpm (steady state, no vac advance) you can pull a rough
Thats 15,000 recorded triggers some of which may be a bit early and some a bit late so the +/- limits can be determined and stored, the same information can be used, specifically across longer drives to map and normalise this jitter and have the software generate the fire signal after it measure a minus it can ad a delay to "normalise" the fire position to what it should be regardless of the jitter. If 2 trigger sensors were used one at TDC and one at 180 degrees it could be made even more accurate.
Big variable is how stable the engine is when at 3K rpm a thats also a tolerance to be compensated for.
Tolerance discussion is all I need for the moment, curves are a different story, with base value I can almost create a set of values to program ffrom a drawing in excel.
I know how much can be done in firmware but anyone a clue on what accuray limits are required in the real world, I am guess about +/- 1.5 deg is OK as most trigger wheels as 120 steps of 3 Degrees. moose549 ???
The actual solution would be to fit one of Mikes Dents ignition system and be done with it but I like an experiment or two now and again.
and although i trust electrionics I certainly do not trust the off the shelf, assembled by the cheapest bidder low end solutions available at present. Plenty commercial drivers and coils available with proven QA, the trigger system and electronics however, very suspect.