David Redszus wrote: ↑Tue Mar 10, 2020 5:49 pm"I have yet to meet the racer (or engine builder) who knows the actual timing curve of his engine while on the track."You're kidding, right?I have confidence the curve seen on a distributor machine and confirmed in the engine, on a dyno or not, is what you get on the track.
For vintage ignitions tuned on a distributor machine, track results are very often affected by shaft end play,
point bounce and jitter, coil over heating, loose electrical connections, cylinder pressure and temperature variations and a whole bunch more.
For electronic ignitions we have measured ignition lag due to switching delays, heat buildup of coil and ignition box and a whole bunch more.
For mapped ignitions, we have measured variances from the map due to input errors, sensor errors and incorrect mapping. With multiple inputs used to drive ignition maps, it is often not possible to accurately predict actual curves.
The cool thing about ECUs and data loggers is that you can see and measure invisible variables.
The sad thing about ECUs and data loggers is that you can see and measure invisible variables.
I have confidence the curve seen on a distributor machine and confirmed in the engine, on a dyno or not, is what you get on the track.
No, are you?You're kidding, right?
Do you own a distributor machine? How much actual experience do you have repairing distributors and using distributor machines to calibrate advance curves, hours, days, years, decades?
Have you ever gathered timing information on a dyno in 500 or 1000 RPM steps through an engine's full RPM range to maximum engine speed, used a distributor machine to apply that information and confirmed the results on the dyno?
You present a good argument that a vintage mechanical distributor can be a more accurate ignition timing device than an ECU. What do you consider a good vintage?